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Re: SVN: Checksum mismatch problem

From: Bruce Korb <bkorb_at_gnu.org>
Date: 2006-05-21 22:14:39 CEST

Florian Weimer wrote:
> * Bruce Korb:
>
>
>>CF: http://gcc.gnu.org/ml/gcc/2005-11/msg00950.html
>> http://gcc.gnu.org/ml/gcc/2005-11/msg00951.html
>>
>>Since Google did not yield an answer, I'm re-asking the question,
>>though with a slightly different file. Help, please, from anybody
>>knowing how to work around the issue. Thank you! - Bruce
>
>
> Could you send us a copy of the
> gcc/ada/.svn/text-base/sem_ch8.adb.svn-base file, preferably in a way
> that is fully binary transparent?

Hopefully, that is the way Thunderbird will MIME encode it. Attached.
Leastwise, the one from my home box is attached. Thanks - Bruce

------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S E M . C H 8 --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2005, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 2, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING. If not, write --
-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
-- Boston, MA 02110-1301, USA. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------

with Atree; use Atree;
with Debug; use Debug;
with Einfo; use Einfo;
with Elists; use Elists;
with Errout; use Errout;
with Exp_Tss; use Exp_Tss;
with Exp_Util; use Exp_Util;
with Fname; use Fname;
with Freeze; use Freeze;
with Lib; use Lib;
with Lib.Load; use Lib.Load;
with Lib.Xref; use Lib.Xref;
with Namet; use Namet;
with Nlists; use Nlists;
with Nmake; use Nmake;
with Opt; use Opt;
with Output; use Output;
with Restrict; use Restrict;
with Rident; use Rident;
with Rtsfind; use Rtsfind;
with Sem; use Sem;
with Sem_Cat; use Sem_Cat;
with Sem_Ch3; use Sem_Ch3;
with Sem_Ch4; use Sem_Ch4;
with Sem_Ch6; use Sem_Ch6;
with Sem_Ch12; use Sem_Ch12;
with Sem_Disp; use Sem_Disp;
with Sem_Dist; use Sem_Dist;
with Sem_Res; use Sem_Res;
with Sem_Util; use Sem_Util;
with Sem_Type; use Sem_Type;
with Stand; use Stand;
with Sinfo; use Sinfo;
with Sinfo.CN; use Sinfo.CN;
with Snames; use Snames;
with Style; use Style;
with Table;
with Tbuild; use Tbuild;
with Uintp; use Uintp;

with GNAT.Spelling_Checker; use GNAT.Spelling_Checker;

package body Sem_Ch8 is

   ------------------------------------
   -- Visibility and Name Resolution --
   ------------------------------------

   -- This package handles name resolution and the collection of
   -- interpretations for overloaded names, prior to overload resolution.

   -- Name resolution is the process that establishes a mapping between source
   -- identifiers and the entities they denote at each point in the program.
   -- Each entity is represented by a defining occurrence. Each identifier
   -- that denotes an entity points to the corresponding defining occurrence.
   -- This is the entity of the applied occurrence. Each occurrence holds
   -- an index into the names table, where source identifiers are stored.

   -- Each entry in the names table for an identifier or designator uses the
   -- Info pointer to hold a link to the currently visible entity that has
   -- this name (see subprograms Get_Name_Entity_Id and Set_Name_Entity_Id
   -- in package Sem_Util). The visibility is initialized at the beginning of
   -- semantic processing to make entities in package Standard immediately
   -- visible. The visibility table is used in a more subtle way when
   -- compiling subunits (see below).

   -- Entities that have the same name (i.e. homonyms) are chained. In the
   -- case of overloaded entities, this chain holds all the possible meanings
   -- of a given identifier. The process of overload resolution uses type
   -- information to select from this chain the unique meaning of a given
   -- identifier.

   -- Entities are also chained in their scope, through the Next_Entity link.
   -- As a consequence, the name space is organized as a sparse matrix, where
   -- each row corresponds to a scope, and each column to a source identifier.
   -- Open scopes, that is to say scopes currently being compiled, have their
   -- corresponding rows of entities in order, innermost scope first.

   -- The scopes of packages that are mentioned in context clauses appear in
   -- no particular order, interspersed among open scopes. This is because
   -- in the course of analyzing the context of a compilation, a package
   -- declaration is first an open scope, and subsequently an element of the
   -- context. If subunits or child units are present, a parent unit may
   -- appear under various guises at various times in the compilation.

   -- When the compilation of the innermost scope is complete, the entities
   -- defined therein are no longer visible. If the scope is not a package
   -- declaration, these entities are never visible subsequently, and can be
   -- removed from visibility chains. If the scope is a package declaration,
   -- its visible declarations may still be accessible. Therefore the entities
   -- defined in such a scope are left on the visibility chains, and only
   -- their visibility (immediately visibility or potential use-visibility)
   -- is affected.

   -- The ordering of homonyms on their chain does not necessarily follow
   -- the order of their corresponding scopes on the scope stack. For
   -- example, if package P and the enclosing scope both contain entities
   -- named E, then when compiling the package body the chain for E will
   -- hold the global entity first, and the local one (corresponding to
   -- the current inner scope) next. As a result, name resolution routines
   -- do not assume any relative ordering of the homonym chains, either
   -- for scope nesting or to order of appearance of context clauses.

   -- When compiling a child unit, entities in the parent scope are always
   -- immediately visible. When compiling the body of a child unit, private
   -- entities in the parent must also be made immediately visible. There
   -- are separate routines to make the visible and private declarations
   -- visible at various times (see package Sem_Ch7).

   -- +--------+ +-----+
   -- | In use |-------->| EU1 |-------------------------->
   -- +--------+ +-----+
   -- | |
   -- +--------+ +-----+ +-----+
   -- | Stand. |---------------->| ES1 |--------------->| ES2 |--->
   -- +--------+ +-----+ +-----+
   -- | |
   -- +---------+ | +-----+
   -- | with'ed |------------------------------>| EW2 |--->
   -- +---------+ | +-----+
   -- | |
   -- +--------+ +-----+ +-----+
   -- | Scope2 |---------------->| E12 |--------------->| E22 |--->
   -- +--------+ +-----+ +-----+
   -- | |
   -- +--------+ +-----+ +-----+
   -- | Scope1 |---------------->| E11 |--------------->| E12 |--->
   -- +--------+ +-----+ +-----+
   -- ^ | |
   -- | | |
   -- | +---------+ | |
   -- | | with'ed |----------------------------------------->
   -- | +---------+ | |
   -- | | |
   -- Scope stack | |
   -- (innermost first) | |
   -- +----------------------------+
   -- Names table => | Id1 | | | | Id2 |
   -- +----------------------------+

   -- Name resolution must deal with several syntactic forms: simple names,
   -- qualified names, indexed names, and various forms of calls.

   -- Each identifier points to an entry in the names table. The resolution
   -- of a simple name consists in traversing the homonym chain, starting
   -- from the names table. If an entry is immediately visible, it is the one
   -- designated by the identifier. If only potentially use-visible entities
   -- are on the chain, we must verify that they do not hide each other. If
   -- the entity we find is overloadable, we collect all other overloadable
   -- entities on the chain as long as they are not hidden.
   --
   -- To resolve expanded names, we must find the entity at the intersection
   -- of the entity chain for the scope (the prefix) and the homonym chain
   -- for the selector. In general, homonym chains will be much shorter than
   -- entity chains, so it is preferable to start from the names table as
   -- well. If the entity found is overloadable, we must collect all other
   -- interpretations that are defined in the scope denoted by the prefix.

   -- For records, protected types, and tasks, their local entities are
   -- removed from visibility chains on exit from the corresponding scope.
   -- From the outside, these entities are always accessed by selected
   -- notation, and the entity chain for the record type, protected type,
   -- etc. is traversed sequentially in order to find the designated entity.

   -- The discriminants of a type and the operations of a protected type or
   -- task are unchained on exit from the first view of the type, (such as
   -- a private or incomplete type declaration, or a protected type speci-
   -- fication) and re-chained when compiling the second view.

   -- In the case of operators, we do not make operators on derived types
   -- explicit. As a result, the notation P."+" may denote either a user-
   -- defined function with name "+", or else an implicit declaration of the
   -- operator "+" in package P. The resolution of expanded names always
   -- tries to resolve an operator name as such an implicitly defined entity,
   -- in addition to looking for explicit declarations.

   -- All forms of names that denote entities (simple names, expanded names,
   -- character literals in some cases) have a Entity attribute, which
   -- identifies the entity denoted by the name.

   ---------------------
   -- The Scope Stack --
   ---------------------

   -- The Scope stack keeps track of the scopes currently been compiled.
   -- Every entity that contains declarations (including records) is placed
   -- on the scope stack while it is being processed, and removed at the end.
   -- Whenever a non-package scope is exited, the entities defined therein
   -- are removed from the visibility table, so that entities in outer scopes
   -- become visible (see previous description). On entry to Sem, the scope
   -- stack only contains the package Standard. As usual, subunits complicate
   -- this picture ever so slightly.

   -- The Rtsfind mechanism can force a call to Semantics while another
   -- compilation is in progress. The unit retrieved by Rtsfind must be
   -- compiled in its own context, and has no access to the visibility of
   -- the unit currently being compiled. The procedures Save_Scope_Stack and
   -- Restore_Scope_Stack make entities in current open scopes invisible
   -- before compiling the retrieved unit, and restore the compilation
   -- environment afterwards.

   ------------------------
   -- Compiling subunits --
   ------------------------

   -- Subunits must be compiled in the environment of the corresponding
   -- stub, that is to say with the same visibility into the parent (and its
   -- context) that is available at the point of the stub declaration, but
   -- with the additional visibility provided by the context clause of the
   -- subunit itself. As a result, compilation of a subunit forces compilation
   -- of the parent (see description in lib-). At the point of the stub
   -- declaration, Analyze is called recursively to compile the proper body
   -- of the subunit, but without reinitializing the names table, nor the
   -- scope stack (i.e. standard is not pushed on the stack). In this fashion
   -- the context of the subunit is added to the context of the parent, and
   -- the subunit is compiled in the correct environment. Note that in the
   -- course of processing the context of a subunit, Standard will appear
   -- twice on the scope stack: once for the parent of the subunit, and
   -- once for the unit in the context clause being compiled. However, the
   -- two sets of entities are not linked by homonym chains, so that the
   -- compilation of any context unit happens in a fresh visibility
   -- environment.

   -------------------------------
   -- Processing of USE Clauses --
   -------------------------------

   -- Every defining occurrence has a flag indicating if it is potentially use
   -- visible. Resolution of simple names examines this flag. The processing
   -- of use clauses consists in setting this flag on all visible entities
   -- defined in the corresponding package. On exit from the scope of the use
   -- clause, the corresponding flag must be reset. However, a package may
   -- appear in several nested use clauses (pathological but legal, alas!)
   -- which forces us to use a slightly more involved scheme:

   -- a) The defining occurrence for a package holds a flag -In_Use- to
   -- indicate that it is currently in the scope of a use clause. If a
   -- redundant use clause is encountered, then the corresponding occurrence
   -- of the package name is flagged -Redundant_Use-.

   -- b) On exit from a scope, the use clauses in its declarative part are
   -- scanned. The visibility flag is reset in all entities declared in
   -- package named in a use clause, as long as the package is not flagged
   -- as being in a redundant use clause (in which case the outer use
   -- clause is still in effect, and the direct visibility of its entities
   -- must be retained).

   -- Note that entities are not removed from their homonym chains on exit
   -- from the package specification. A subsequent use clause does not need
   -- to rechain the visible entities, but only to establish their direct
   -- visibility.

   -----------------------------------
   -- Handling private declarations --
   -----------------------------------

   -- The principle that each entity has a single defining occurrence clashes
   -- with the presence of two separate definitions for private types: the
   -- first is the private type declaration, and second is the full type
   -- declaration. It Is important that all references to the type point to
   -- the same defining occurrence, namely the first one. To enforce the two
   -- separate views of the entity, the corresponding information is swapped
   -- between the two declarations. Outside of the package, the defining
   -- occurrence only contains the private declaration information, while in
   -- the private part and the body of the package the defining occurrence
   -- contains the full declaration. To simplify the swap, the defining
   -- occurrence that currently holds the private declaration points to the
   -- full declaration. During semantic processing the defining occurrence
   -- also points to a list of private dependents, that is to say access
   -- types or composite types whose designated types or component types are
   -- subtypes or derived types of the private type in question. After the
   -- full declaration has been seen, the private dependents are updated to
   -- indicate that they have full definitions.

   ------------------------------------
   -- Handling of Undefined Messages --
   ------------------------------------

   -- In normal mode, only the first use of an undefined identifier generates
   -- a message. The table Urefs is used to record error messages that have
   -- been issued so that second and subsequent ones do not generate further
   -- messages. However, the second reference causes text to be added to the
   -- original undefined message noting "(more references follow)". The
   -- full error list option (-gnatf) forces messages to be generated for
   -- every reference and disconnects the use of this table.

   type Uref_Entry is record
      Node : Node_Id;
      -- Node for identifier for which original message was posted. The
      -- Chars field of this identifier is used to detect later references
      -- to the same identifier.

      Err : Error_Msg_Id;
      -- Records error message Id of original undefined message. Reset to
      -- No_Error_Msg after the second occurrence, where it is used to add
      -- text to the original message as described above.

      Nvis : Boolean;
      -- Set if the message is not visible rather than undefined

      Loc : Source_Ptr;
      -- Records location of error message. Used to make sure that we do
      -- not consider a, b : undefined as two separate instances, which
      -- would otherwise happen, since the parser converts this sequence
      -- to a : undefined; b : undefined.

   end record;

   package Urefs is new Table.Table (
     Table_Component_Type => Uref_Entry,
     Table_Index_Type => Nat,
     Table_Low_Bound => 1,
     Table_Initial => 10,
     Table_Increment => 100,
     Table_Name => "Urefs");

   Candidate_Renaming : Entity_Id;
   -- Holds a candidate interpretation that appears in a subprogram renaming
   -- declaration and does not match the given specification, but matches at
   -- least on the first formal. Allows better error message when given
   -- specification omits defaulted parameters, a common error.

   -----------------------
   -- Local Subprograms --
   -----------------------

   procedure Analyze_Generic_Renaming
     (N : Node_Id;
      K : Entity_Kind);
   -- Common processing for all three kinds of generic renaming declarations.
   -- Enter new name and indicate that it renames the generic unit.

   procedure Analyze_Renamed_Character
     (N : Node_Id;
      New_S : Entity_Id;
      Is_Body : Boolean);
   -- Renamed entity is given by a character literal, which must belong
   -- to the return type of the new entity. Is_Body indicates whether the
   -- declaration is a renaming_as_body. If the original declaration has
   -- already been frozen (because of an intervening body, e.g.) the body of
   -- the function must be built now. The same applies to the following
   -- various renaming procedures.

   procedure Analyze_Renamed_Dereference
     (N : Node_Id;
      New_S : Entity_Id;
      Is_Body : Boolean);
   -- Renamed entity is given by an explicit dereference. Prefix must be a
   -- conformant access_to_subprogram type.

   procedure Analyze_Renamed_Entry
     (N : Node_Id;
      New_S : Entity_Id;
      Is_Body : Boolean);
   -- If the renamed entity in a subprogram renaming is an entry or protected
   -- subprogram, build a body for the new entity whose only statement is a
   -- call to the renamed entity.

   procedure Analyze_Renamed_Family_Member
     (N : Node_Id;
      New_S : Entity_Id;
      Is_Body : Boolean);
   -- Used when the renamed entity is an indexed component. The prefix must
   -- denote an entry family.

   function Applicable_Use (Pack_Name : Node_Id) return Boolean;
   -- Common code to Use_One_Package and Set_Use, to determine whether
   -- use clause must be processed. Pack_Name is an entity name that
   -- references the package in question.

   procedure Attribute_Renaming (N : Node_Id);
   -- Analyze renaming of attribute as function. The renaming declaration N
   -- is rewritten as a function body that returns the attribute reference
   -- applied to the formals of the function.

   procedure Check_Frozen_Renaming (N : Node_Id; Subp : Entity_Id);
   -- A renaming_as_body may occur after the entity of the original decla-
   -- ration has been frozen. In that case, the body of the new entity must
   -- be built now, because the usual mechanism of building the renamed
   -- body at the point of freezing will not work. Subp is the subprogram
   -- for which N provides the Renaming_As_Body.

   procedure Check_In_Previous_With_Clause
     (N : Node_Id;
      Nam : Node_Id);
   -- N is a use_package clause and Nam the package name, or N is a use_type
   -- clause and Nam is the prefix of the type name. In either case, verify
   -- that the package is visible at that point in the context: either it
   -- appears in a previous with_clause, or because it is a fully qualified
   -- name and the root ancestor appears in a previous with_clause.

   procedure Check_Library_Unit_Renaming (N : Node_Id; Old_E : Entity_Id);
   -- Verify that the entity in a renaming declaration that is a library unit
   -- is itself a library unit and not a nested unit or subunit. Also check
   -- that if the renaming is a child unit of a generic parent, then the
   -- renamed unit must also be a child unit of that parent. Finally, verify
   -- that a renamed generic unit is not an implicit child declared within
   -- an instance of the parent.

   procedure Chain_Use_Clause (N : Node_Id);
   -- Chain use clause onto list of uses clauses headed by First_Use_Clause in
   -- the proper scope table entry. This is usually the current scope, but it
   -- will be an inner scope when installing the use clauses of the private
   -- declarations of a parent unit prior to compiling the private part of a
   -- child unit. This chain is traversed when installing/removing use clauses
   -- when compiling a subunit or instantiating a generic body on the fly,
   -- when it is necessary to save and restore full environments.

   function Has_Implicit_Character_Literal (N : Node_Id) return Boolean;
   -- Find a type derived from Character or Wide_Character in the prefix of N.
   -- Used to resolved qualified names whose selector is a character literal.

   function Has_Private_With (E : Entity_Id) return Boolean;
   -- Ada 2005 (AI-262): Determines if the current compilation unit has a
   -- private with on E

   procedure Find_Expanded_Name (N : Node_Id);
   -- Selected component is known to be expanded name. Verify legality
   -- of selector given the scope denoted by prefix.

   function Find_Renamed_Entity
     (N : Node_Id;
      Nam : Node_Id;
      New_S : Entity_Id;
      Is_Actual : Boolean := False) return Entity_Id;
   -- Find the renamed entity that corresponds to the given parameter profile
   -- in a subprogram renaming declaration. The renamed entity may be an
   -- operator, a subprogram, an entry, or a protected operation. Is_Actual
   -- indicates that the renaming is the one generated for an actual subpro-
   -- gram in an instance, for which special visibility checks apply.

   function Has_Implicit_Operator (N : Node_Id) return Boolean;
   -- N is an expanded name whose selector is an operator name (eg P."+").
   -- A declarative part contains an implicit declaration of an operator
   -- if it has a declaration of a type to which one of the predefined
   -- operators apply. The existence of this routine is an artifact of
   -- our implementation: a more straightforward but more space-consuming
   -- choice would be to make all inherited operators explicit in the
   -- symbol table.

   procedure Inherit_Renamed_Profile (New_S : Entity_Id; Old_S : Entity_Id);
   -- A subprogram defined by a renaming declaration inherits the parameter
   -- profile of the renamed entity. The subtypes given in the subprogram
   -- specification are discarded and replaced with those of the renamed
   -- subprogram, which are then used to recheck the default values.

   function Is_Appropriate_For_Record (T : Entity_Id) return Boolean;
   -- Prefix is appropriate for record if it is of a record type, or
   -- an access to such.

   function Is_Appropriate_For_Entry_Prefix (T : Entity_Id) return Boolean;
   -- True if it is of a task type, a protected type, or else an access
   -- to one of these types.

   procedure Note_Redundant_Use (Clause : Node_Id);
   -- Mark the name in a use clause as redundant if the corresponding
   -- entity is already use-visible. Emit a warning if the use clause
   -- comes from source and the proper warnings are enabled.

   procedure Premature_Usage (N : Node_Id);
   -- Diagnose usage of an entity before it is visible

   procedure Use_One_Package (P : Entity_Id; N : Node_Id);
   -- Make visible entities declared in package P potentially use-visible
   -- in the current context. Also used in the analysis of subunits, when
   -- re-installing use clauses of parent units. N is the use_clause that
   -- names P (and possibly other packages).

   procedure Use_One_Type (Id : Node_Id);
   -- Id is the subtype mark from a use type clause. This procedure makes
   -- the primitive operators of the type potentially use-visible.

   procedure Write_Info;
   -- Write debugging information on entities declared in current scope

   procedure Write_Scopes;
   pragma Warnings (Off, Write_Scopes);
   -- Debugging information: dump all entities on scope stack

   --------------------------------
   -- Analyze_Exception_Renaming --
   --------------------------------

   -- The language only allows a single identifier, but the tree holds
   -- an identifier list. The parser has already issued an error message
   -- if there is more than one element in the list.

   procedure Analyze_Exception_Renaming (N : Node_Id) is
      Id : constant Node_Id := Defining_Identifier (N);
      Nam : constant Node_Id := Name (N);

   begin
      Enter_Name (Id);
      Analyze (Nam);

      Set_Ekind (Id, E_Exception);
      Set_Exception_Code (Id, Uint_0);
      Set_Etype (Id, Standard_Exception_Type);
      Set_Is_Pure (Id, Is_Pure (Current_Scope));

      if not Is_Entity_Name (Nam) or else
        Ekind (Entity (Nam)) /= E_Exception
      then
         Error_Msg_N ("invalid exception name in renaming", Nam);
      else
         if Present (Renamed_Object (Entity (Nam))) then
            Set_Renamed_Object (Id, Renamed_Object (Entity (Nam)));
         else
            Set_Renamed_Object (Id, Entity (Nam));
         end if;
      end if;
   end Analyze_Exception_Renaming;

   ---------------------------
   -- Analyze_Expanded_Name --
   ---------------------------

   procedure Analyze_Expanded_Name (N : Node_Id) is
   begin
      -- If the entity pointer is already set, this is an internal node, or
      -- a node that is analyzed more than once, after a tree modification.
      -- In such a case there is no resolution to perform, just set the type.
      -- For completeness, analyze prefix as well.

      if Present (Entity (N)) then
         if Is_Type (Entity (N)) then
            Set_Etype (N, Entity (N));
         else
            Set_Etype (N, Etype (Entity (N)));
         end if;

         Analyze (Prefix (N));
         return;
      else
         Find_Expanded_Name (N);
      end if;
   end Analyze_Expanded_Name;

   ---------------------------------------
   -- Analyze_Generic_Function_Renaming --
   ---------------------------------------

   procedure Analyze_Generic_Function_Renaming (N : Node_Id) is
   begin
      Analyze_Generic_Renaming (N, E_Generic_Function);
   end Analyze_Generic_Function_Renaming;

   --------------------------------------
   -- Analyze_Generic_Package_Renaming --
   --------------------------------------

   procedure Analyze_Generic_Package_Renaming (N : Node_Id) is
   begin
      -- Apply the Text_IO Kludge here, since we may be renaming
      -- one of the subpackages of Text_IO, then join common routine.

      Text_IO_Kludge (Name (N));

      Analyze_Generic_Renaming (N, E_Generic_Package);
   end Analyze_Generic_Package_Renaming;

   ----------------------------------------
   -- Analyze_Generic_Procedure_Renaming --
   ----------------------------------------

   procedure Analyze_Generic_Procedure_Renaming (N : Node_Id) is
   begin
      Analyze_Generic_Renaming (N, E_Generic_Procedure);
   end Analyze_Generic_Procedure_Renaming;

   ------------------------------
   -- Analyze_Generic_Renaming --
   ------------------------------

   procedure Analyze_Generic_Renaming
     (N : Node_Id;
      K : Entity_Kind)
   is
      New_P : constant Entity_Id := Defining_Entity (N);
      Old_P : Entity_Id;
      Inst : Boolean := False; -- prevent junk warning

   begin
      if Name (N) = Error then
         return;
      end if;

      Generate_Definition (New_P);

      if Current_Scope /= Standard_Standard then
         Set_Is_Pure (New_P, Is_Pure (Current_Scope));
      end if;

      if Nkind (Name (N)) = N_Selected_Component then
         Check_Generic_Child_Unit (Name (N), Inst);
      else
         Analyze (Name (N));
      end if;

      if not Is_Entity_Name (Name (N)) then
         Error_Msg_N ("expect entity name in renaming declaration", Name (N));
         Old_P := Any_Id;
      else
         Old_P := Entity (Name (N));
      end if;

      Enter_Name (New_P);
      Set_Ekind (New_P, K);

      if Etype (Old_P) = Any_Type then
         null;

      elsif Ekind (Old_P) /= K then
         Error_Msg_N ("invalid generic unit name", Name (N));

      else
         if Present (Renamed_Object (Old_P)) then
            Set_Renamed_Object (New_P, Renamed_Object (Old_P));
         else
            Set_Renamed_Object (New_P, Old_P);
         end if;

         Set_Etype (New_P, Etype (Old_P));
         Set_Has_Completion (New_P);

         if In_Open_Scopes (Old_P) then
            Error_Msg_N ("within its scope, generic denotes its instance", N);
         end if;

         Check_Library_Unit_Renaming (N, Old_P);
      end if;

   end Analyze_Generic_Renaming;

   -----------------------------
   -- Analyze_Object_Renaming --
   -----------------------------

   procedure Analyze_Object_Renaming (N : Node_Id) is
      Id : constant Entity_Id := Defining_Identifier (N);
      Dec : Node_Id;
      Nam : constant Node_Id := Name (N);
      T : Entity_Id;
      T2 : Entity_Id;

   begin
      if Nam = Error then
         return;
      end if;

      Set_Is_Pure (Id, Is_Pure (Current_Scope));
      Enter_Name (Id);

      -- The renaming of a component that depends on a discriminant
      -- requires an actual subtype, because in subsequent use of the object
      -- Gigi will be unable to locate the actual bounds. This explicit step
      -- is required when the renaming is generated in removing side effects
      -- of an already-analyzed expression.

      if Nkind (Nam) = N_Selected_Component
        and then Analyzed (Nam)
      then
         T := Etype (Nam);
         Dec := Build_Actual_Subtype_Of_Component (Etype (Nam), Nam);

         if Present (Dec) then
            Insert_Action (N, Dec);
            T := Defining_Identifier (Dec);
            Set_Etype (Nam, T);
         end if;

      elsif Present (Subtype_Mark (N)) then
         Find_Type (Subtype_Mark (N));
         T := Entity (Subtype_Mark (N));
         Analyze_And_Resolve (Nam, T);

      -- Ada 2005 (AI-230/AI-254): Access renaming

      else pragma Assert (Present (Access_Definition (N)));
         T := Access_Definition
                (Related_Nod => N,
                 N => Access_Definition (N));

         Analyze_And_Resolve (Nam, T);

         -- Ada 2005 (AI-231): "In the case where the type is defined by an
         -- access_definition, the renamed entity shall be of an access-to-
         -- constant type if and only if the access_definition defines an
         -- access-to-constant type" ARM 8.5.1(4)

         if Constant_Present (Access_Definition (N))
           and then not Is_Access_Constant (Etype (Nam))
         then
            Error_Msg_N ("(Ada 2005): the renamed object is not "
                         & "access-to-constant ('R'M 8.5.1(6))", N);

         elsif Null_Exclusion_Present (Access_Definition (N)) then
            Error_Msg_N ("(Ada 2005): null-excluding attribute ignored "
                         & "('R'M 8.5.1(6))?", N);
         end if;
      end if;

      -- An object renaming requires an exact match of the type;
      -- class-wide matching is not allowed.

      if Is_Class_Wide_Type (T)
        and then Base_Type (Etype (Nam)) /= Base_Type (T)
      then
         Wrong_Type (Nam, T);
      end if;

      T2 := Etype (Nam);

      -- (Ada 2005: AI-326): Handle wrong use of incomplete type

      if Nkind (Nam) = N_Explicit_Dereference
        and then Ekind (Etype (T2)) = E_Incomplete_Type
      then
         Error_Msg_N ("invalid use of incomplete type", Id);
         return;
      end if;

      Set_Ekind (Id, E_Variable);
      Init_Size_Align (Id);

      if T = Any_Type or else Etype (Nam) = Any_Type then
         return;

      -- Verify that the renamed entity is an object or a function call.
      -- It may have been rewritten in several ways.

      elsif Is_Object_Reference (Nam) then
         if Comes_From_Source (N)
           and then Is_Dependent_Component_Of_Mutable_Object (Nam)
         then
            Error_Msg_N
              ("illegal renaming of discriminant-dependent component", Nam);
         else
            null;
         end if;

      -- A static function call may have been folded into a literal

      elsif Nkind (Original_Node (Nam)) = N_Function_Call

            -- When expansion is disabled, attribute reference is not
            -- rewritten as function call. Otherwise it may be rewritten
            -- as a conversion, so check original node.

        or else (Nkind (Original_Node (Nam)) = N_Attribute_Reference
                  and then Is_Function_Attribute_Name
                    (Attribute_Name (Original_Node (Nam))))

            -- Weird but legal, equivalent to renaming a function call
            -- Illegal if the literal is the result of constant-folding
            -- an attribute reference that is not a function.

        or else (Is_Entity_Name (Nam)
                  and then Ekind (Entity (Nam)) = E_Enumeration_Literal
                  and then
                    Nkind (Original_Node (Nam)) /= N_Attribute_Reference)

        or else (Nkind (Nam) = N_Type_Conversion
                    and then Is_Tagged_Type (Entity (Subtype_Mark (Nam))))
      then
         null;

      else
         if Nkind (Nam) = N_Type_Conversion then
            Error_Msg_N
              ("renaming of conversion only allowed for tagged types", Nam);

         else
            Error_Msg_N ("expect object name in renaming", Nam);
         end if;
      end if;

      Set_Etype (Id, T2);

      if not Is_Variable (Nam) then
         Set_Ekind (Id, E_Constant);
         Set_Never_Set_In_Source (Id, True);
         Set_Is_True_Constant (Id, True);
      end if;

      Set_Renamed_Object (Id, Nam);
   end Analyze_Object_Renaming;

   ------------------------------
   -- Analyze_Package_Renaming --
   ------------------------------

   procedure Analyze_Package_Renaming (N : Node_Id) is
      New_P : constant Entity_Id := Defining_Entity (N);
      Old_P : Entity_Id;
      Spec : Node_Id;

   begin
      if Name (N) = Error then
         return;
      end if;

      -- Apply Text_IO kludge here, since we may be renaming one of
      -- the children of Text_IO

      Text_IO_Kludge (Name (N));

      if Current_Scope /= Standard_Standard then
         Set_Is_Pure (New_P, Is_Pure (Current_Scope));
      end if;

      Enter_Name (New_P);
      Analyze (Name (N));
      if Is_Entity_Name (Name (N)) then
         Old_P := Entity (Name (N));
      else
         Old_P := Any_Id;
      end if;

      if Etype (Old_P) = Any_Type then
         Error_Msg_N
           ("expect package name in renaming", Name (N));

      -- Ada 2005 (AI-50217): Limited withed packages cannot be renamed

      elsif Ekind (Old_P) = E_Package
        and then From_With_Type (Old_P)
      then
         Error_Msg_N
           ("limited withed package cannot be renamed", Name (N));

      elsif Ekind (Old_P) /= E_Package
        and then not (Ekind (Old_P) = E_Generic_Package
                       and then In_Open_Scopes (Old_P))
      then
         if Ekind (Old_P) = E_Generic_Package then
            Error_Msg_N
               ("generic package cannot be renamed as a package", Name (N));
         else
            Error_Msg_Sloc := Sloc (Old_P);
            Error_Msg_NE
             ("expect package name in renaming, found& declared#",
               Name (N), Old_P);
         end if;

         -- Set basic attributes to minimize cascaded errors

         Set_Ekind (New_P, E_Package);
         Set_Etype (New_P, Standard_Void_Type);

      else
         -- Entities in the old package are accessible through the
         -- renaming entity. The simplest implementation is to have
         -- both packages share the entity list.

         Set_Ekind (New_P, E_Package);
         Set_Etype (New_P, Standard_Void_Type);

         if Present (Renamed_Object (Old_P)) then
            Set_Renamed_Object (New_P, Renamed_Object (Old_P));
         else
            Set_Renamed_Object (New_P, Old_P);
         end if;

         Set_Has_Completion (New_P);

         Set_First_Entity (New_P, First_Entity (Old_P));
         Set_Last_Entity (New_P, Last_Entity (Old_P));
         Set_First_Private_Entity (New_P, First_Private_Entity (Old_P));
         Check_Library_Unit_Renaming (N, Old_P);
         Generate_Reference (Old_P, Name (N));

         -- If this is the renaming declaration of a package instantiation
         -- within itself, it is the declaration that ends the list of actuals
         -- for the instantiation. At this point, the subtypes that rename
         -- the actuals are flagged as generic, to avoid spurious ambiguities
         -- if the actuals for two distinct formals happen to coincide. If
         -- the actual is a private type, the subtype has a private completion
         -- that is flagged in the same fashion.

         -- Resolution is identical to what is was in the original generic.
         -- On exit from the generic instance, these are turned into regular
         -- subtypes again, so they are compatible with types in their class.

         if not Is_Generic_Instance (Old_P) then
            return;
         else
            Spec := Specification (Unit_Declaration_Node (Old_P));
         end if;

         if Nkind (Spec) = N_Package_Specification
           and then Present (Generic_Parent (Spec))
           and then Old_P = Current_Scope
           and then Chars (New_P) = Chars (Generic_Parent (Spec))
         then
            declare
               E : Entity_Id := First_Entity (Old_P);
            begin
               while Present (E)
                 and then E /= New_P
               loop
                  if Is_Type (E)
                    and then Nkind (Parent (E)) = N_Subtype_Declaration
                  then
                     Set_Is_Generic_Actual_Type (E);

                     if Is_Private_Type (E)
                       and then Present (Full_View (E))
                     then
                        Set_Is_Generic_Actual_Type (Full_View (E));
                     end if;
                  end if;

                  Next_Entity (E);
               end loop;
            end;
         end if;
      end if;

   end Analyze_Package_Renaming;

   -------------------------------
   -- Analyze_Renamed_Character --
   -------------------------------

   procedure Analyze_Renamed_Character
     (N : Node_Id;
      New_S : Entity_Id;
      Is_Body : Boolean)
   is
      C : constant Node_Id := Name (N);

   begin
      if Ekind (New_S) = E_Function then
         Resolve (C, Etype (New_S));

         if Is_Body then
            Check_Frozen_Renaming (N, New_S);
         end if;

      else
         Error_Msg_N ("character literal can only be renamed as function", N);
      end if;
   end Analyze_Renamed_Character;

   ---------------------------------
   -- Analyze_Renamed_Dereference --
   ---------------------------------

   procedure Analyze_Renamed_Dereference
     (N : Node_Id;
      New_S : Entity_Id;
      Is_Body : Boolean)
   is
      Nam : constant Node_Id := Name (N);
      P : constant Node_Id := Prefix (Nam);
      Typ : Entity_Id;
      Ind : Interp_Index;
      It : Interp;

   begin
      if not Is_Overloaded (P) then
         if Ekind (Etype (Nam)) /= E_Subprogram_Type
           or else not Type_Conformant (Etype (Nam), New_S) then
            Error_Msg_N ("designated type does not match specification", P);
         else
            Resolve (P);
         end if;

         return;

      else
         Typ := Any_Type;
         Get_First_Interp (Nam, Ind, It);

         while Present (It.Nam) loop

            if Ekind (It.Nam) = E_Subprogram_Type
              and then Type_Conformant (It.Nam, New_S) then

               if Typ /= Any_Id then
                  Error_Msg_N ("ambiguous renaming", P);
                  return;
               else
                  Typ := It.Nam;
               end if;
            end if;

            Get_Next_Interp (Ind, It);
         end loop;

         if Typ = Any_Type then
            Error_Msg_N ("designated type does not match specification", P);
         else
            Resolve (N, Typ);

            if Is_Body then
               Check_Frozen_Renaming (N, New_S);
            end if;
         end if;
      end if;
   end Analyze_Renamed_Dereference;

   ---------------------------
   -- Analyze_Renamed_Entry --
   ---------------------------

   procedure Analyze_Renamed_Entry
     (N : Node_Id;
      New_S : Entity_Id;
      Is_Body : Boolean)
   is
      Nam : constant Node_Id := Name (N);
      Sel : constant Node_Id := Selector_Name (Nam);
      Old_S : Entity_Id;

   begin
      if Entity (Sel) = Any_Id then

         -- Selector is undefined on prefix. Error emitted already

         Set_Has_Completion (New_S);
         return;
      end if;

      -- Otherwise, find renamed entity, and build body of New_S as a call
      -- to it.

      Old_S := Find_Renamed_Entity (N, Selector_Name (Nam), New_S);

      if Old_S = Any_Id then
         Error_Msg_N (" no subprogram or entry matches specification", N);
      else
         if Is_Body then
            Check_Subtype_Conformant (New_S, Old_S, N);
            Generate_Reference (New_S, Defining_Entity (N), 'b');
            Style.Check_Identifier (Defining_Entity (N), New_S);

         else
            -- Only mode conformance required for a renaming_as_declaration

            Check_Mode_Conformant (New_S, Old_S, N);
         end if;

         Inherit_Renamed_Profile (New_S, Old_S);
      end if;

      Set_Convention (New_S, Convention (Old_S));
      Set_Has_Completion (New_S, Inside_A_Generic);

      if Is_Body then
         Check_Frozen_Renaming (N, New_S);
      end if;
   end Analyze_Renamed_Entry;

   -----------------------------------
   -- Analyze_Renamed_Family_Member --
   -----------------------------------

   procedure Analyze_Renamed_Family_Member
     (N : Node_Id;
      New_S : Entity_Id;
      Is_Body : Boolean)
   is
      Nam : constant Node_Id := Name (N);
      P : constant Node_Id := Prefix (Nam);
      Old_S : Entity_Id;

   begin
      if (Is_Entity_Name (P) and then Ekind (Entity (P)) = E_Entry_Family)
        or else (Nkind (P) = N_Selected_Component
                   and then
                 Ekind (Entity (Selector_Name (P))) = E_Entry_Family)
      then
         if Is_Entity_Name (P) then
            Old_S := Entity (P);
         else
            Old_S := Entity (Selector_Name (P));
         end if;

         if not Entity_Matches_Spec (Old_S, New_S) then
            Error_Msg_N ("entry family does not match specification", N);

         elsif Is_Body then
            Check_Subtype_Conformant (New_S, Old_S, N);
            Generate_Reference (New_S, Defining_Entity (N), 'b');
            Style.Check_Identifier (Defining_Entity (N), New_S);
         end if;
      else
         Error_Msg_N ("no entry family matches specification", N);
      end if;

      Set_Has_Completion (New_S, Inside_A_Generic);

      if Is_Body then
         Check_Frozen_Renaming (N, New_S);
      end if;
   end Analyze_Renamed_Family_Member;

   ---------------------------------
   -- Analyze_Subprogram_Renaming --
   ---------------------------------

   procedure Analyze_Subprogram_Renaming (N : Node_Id) is
      Spec : constant Node_Id := Specification (N);
      Save_AV : constant Ada_Version_Type := Ada_Version;
      Save_AV_Exp : constant Ada_Version_Type := Ada_Version_Explicit;
      Nam : constant Node_Id := Name (N);
      New_S : Entity_Id;
      Old_S : Entity_Id := Empty;
      Rename_Spec : Entity_Id;
      Formal_Spec : constant Node_Id := Corresponding_Formal_Spec (N);
      Is_Actual : constant Boolean := Present (Formal_Spec);
      Inst_Node : Node_Id := Empty;

      function Original_Subprogram (Subp : Entity_Id) return Entity_Id;
      -- Find renamed entity when the declaration is a renaming_as_body
      -- and the renamed entity may itself be a renaming_as_body. Used to
      -- enforce rule that a renaming_as_body is illegal if the declaration
      -- occurs before the subprogram it completes is frozen, and renaming
      -- indirectly renames the subprogram itself.(Defect Report 8652/0027).

      -------------------------
      -- Original_Subprogram --
      -------------------------

      function Original_Subprogram (Subp : Entity_Id) return Entity_Id is
         Orig_Decl : Node_Id;
         Orig_Subp : Entity_Id;

      begin
         -- First case: renamed entity is itself a renaming

         if Present (Alias (Subp)) then
            return Alias (Subp);

         elsif
           Nkind (Unit_Declaration_Node (Subp)) = N_Subprogram_Declaration
             and then Present
              (Corresponding_Body (Unit_Declaration_Node (Subp)))
         then
            -- Check if renamed entity is a renaming_as_body

            Orig_Decl :=
              Unit_Declaration_Node
                (Corresponding_Body (Unit_Declaration_Node (Subp)));

            if Nkind (Orig_Decl) = N_Subprogram_Renaming_Declaration then
               Orig_Subp := Entity (Name (Orig_Decl));

               if Orig_Subp = Rename_Spec then

                  -- Circularity detected

                  return Orig_Subp;

               else
                  return (Original_Subprogram (Orig_Subp));
               end if;
            else
               return Subp;
            end if;
         else
            return Subp;
         end if;
      end Original_Subprogram;

   -- Start of processing for Analyze_Subprogram_Renaming

   begin
      -- We must test for the attribute renaming case before the Analyze
      -- call because otherwise Sem_Attr will complain that the attribute
      -- is missing an argument when it is analyzed.

      if Nkind (Nam) = N_Attribute_Reference then

         -- In the case of an abstract formal subprogram association,
         -- rewrite an actual given by a stream attribute as the name
         -- of the corresponding stream primitive of the type.

         -- In a generic context the stream operations are not generated,
         -- and this must be treated as a normal attribute reference, to
         -- be expanded in subsequent instantiations.

         if Is_Actual and then Is_Abstract (Formal_Spec)
           and then Expander_Active
         then
            declare
               Stream_Prim : Entity_Id;
               Prefix_Type : constant Entity_Id := Entity (Prefix (Nam));

            begin
               -- The class-wide forms of the stream attributes are not
               -- primitive dispatching operations (even though they
               -- internally dispatch to a stream attribute).

               if Is_Class_Wide_Type (Prefix_Type) then
                  Error_Msg_N
                    ("attribute must be a primitive dispatching operation",
                     Nam);
                  return;
               end if;

               -- Retrieve the primitive subprogram associated with the
               -- attribute. This can only be a stream attribute, since
               -- those are the only ones that are dispatching (and the
               -- actual for an abstract formal subprogram must be a
               -- dispatching operation).

               case Attribute_Name (Nam) is
                  when Name_Input =>
                     Stream_Prim :=
                       Find_Prim_Op (Prefix_Type, TSS_Stream_Input);
                  when Name_Output =>
                     Stream_Prim :=
                       Find_Prim_Op (Prefix_Type, TSS_Stream_Output);
                  when Name_Read =>
                     Stream_Prim :=
                       Find_Prim_Op (Prefix_Type, TSS_Stream_Read);
                  when Name_Write =>
                     Stream_Prim :=
                       Find_Prim_Op (Prefix_Type, TSS_Stream_Write);
                  when others =>
                     Error_Msg_N
                       ("attribute must be a primitive dispatching operation",
                        Nam);
                     return;
               end case;

               -- Rewrite the attribute into the name of its corresponding
               -- primitive dispatching subprogram. We can then proceed with
               -- the usual processing for subprogram renamings.

               declare
                  Prim_Name : constant Node_Id :=
                                Make_Identifier (Sloc (Nam),
                                  Chars => Chars (Stream_Prim));
               begin
                  Set_Entity (Prim_Name, Stream_Prim);
                  Rewrite (Nam, Prim_Name);
                  Analyze (Nam);
               end;
            end;

         -- Normal processing for a renaming of an attribute

         else
            Attribute_Renaming (N);
            return;
         end if;
      end if;

      -- Check whether this declaration corresponds to the instantiation
      -- of a formal subprogram.

      -- If this is an instantiation, the corresponding actual is frozen
      -- and error messages can be made more precise. If this is a default
      -- subprogram, the entity is already established in the generic, and
      -- is not retrieved by visibility. If it is a default with a box, the
      -- candidate interpretations, if any, have been collected when building
      -- the renaming declaration. If overloaded, the proper interpretation
      -- is determined in Find_Renamed_Entity. If the entity is an operator,
      -- Find_Renamed_Entity applies additional visibility checks.

      if Is_Actual then
         Inst_Node := Unit_Declaration_Node (Formal_Spec);

         if Is_Entity_Name (Nam)
           and then Present (Entity (Nam))
           and then not Comes_From_Source (Nam)
           and then not Is_Overloaded (Nam)
         then
            Old_S := Entity (Nam);
            New_S := Analyze_Subprogram_Specification (Spec);

            -- Operator case

            if Ekind (Entity (Nam)) = E_Operator then

               -- Box present

               if Box_Present (Inst_Node) then
                  Old_S := Find_Renamed_Entity (N, Name (N), New_S, Is_Actual);

               -- If there is an immediately visible homonym of the operator
               -- and the declaration has a default, this is worth a warning
               -- because the user probably did not intend to get the pre-
               -- defined operator, visible in the generic declaration.
               -- To find if there is an intended candidate, analyze the
               -- renaming again in the current context.

               elsif Scope (Old_S) = Standard_Standard
                 and then Present (Default_Name (Inst_Node))
               then
                  declare
                     Decl : constant Node_Id := New_Copy_Tree (N);
                     Hidden : Entity_Id;

                  begin
                     Set_Entity (Name (Decl), Empty);
                     Analyze (Name (Decl));
                     Hidden :=
                       Find_Renamed_Entity (Decl, Name (Decl), New_S, True);

                     if Present (Hidden)
                       and then In_Open_Scopes (Scope (Hidden))
                       and then Is_Immediately_Visible (Hidden)
                       and then Comes_From_Source (Hidden)
                       and then Hidden /= Old_S
                     then
                        Error_Msg_Sloc := Sloc (Hidden);
                        Error_Msg_N ("?default subprogram is resolved " &
                                     "in the generic declaration " &
                                     "('R'M 12.6(17))", N);
                        Error_Msg_NE ("\?and will not use & #", N, Hidden);
                     end if;
                  end;
               end if;
            end if;

         else
            Analyze (Nam);
            New_S := Analyze_Subprogram_Specification (Spec);
         end if;

      else
         -- Renamed entity must be analyzed first, to avoid being hidden by
         -- new name (which might be the same in a generic instance).

         Analyze (Nam);

         -- The renaming defines a new overloaded entity, which is analyzed
         -- like a subprogram declaration.

         New_S := Analyze_Subprogram_Specification (Spec);
      end if;

      if Current_Scope /= Standard_Standard then
         Set_Is_Pure (New_S, Is_Pure (Current_Scope));
      end if;

      Rename_Spec := Find_Corresponding_Spec (N);

      if Present (Rename_Spec) then

         -- Renaming_As_Body. Renaming declaration is the completion of
         -- the declaration of Rename_Spec. We will build an actual body
         -- for it at the freezing point.

         Set_Corresponding_Spec (N, Rename_Spec);
         if Nkind (Unit_Declaration_Node (Rename_Spec)) =
                                     N_Abstract_Subprogram_Declaration
         then
            -- Input and Output stream functions are abstract if the object
            -- type is abstract. However, these functions may receive explicit
            -- declarations in representation clauses, making the attribute
            -- subprograms usable as defaults in subsequent type extensions.
            -- In this case we rewrite the declaration to make the subprogram
            -- non-abstract. We remove the previous declaration, and insert
            -- the new one at the point of the renaming, to prevent premature
            -- access to unfrozen types. The new declaration reuses the
            -- specification of the previous one, and must not be analyzed.

            pragma Assert (Is_TSS (Rename_Spec, TSS_Stream_Output)
                           or else Is_TSS (Rename_Spec, TSS_Stream_Input));

            declare
               Old_Decl : constant Node_Id :=
                            Unit_Declaration_Node (Rename_Spec);
               New_Decl : constant Node_Id :=
                            Make_Subprogram_Declaration (Sloc (N),
                              Specification =>
                                Relocate_Node (Specification (Old_Decl)));
            begin
               Remove (Old_Decl);
               Insert_After (N, New_Decl);
               Set_Is_Abstract (Rename_Spec, False);
               Set_Analyzed (New_Decl);
            end;
         end if;

         Set_Corresponding_Body (Unit_Declaration_Node (Rename_Spec), New_S);

         if Ada_Version = Ada_83 and then Comes_From_Source (N) then
            Error_Msg_N ("(Ada 83) renaming cannot serve as a body", N);
         end if;

         Set_Convention (New_S, Convention (Rename_Spec));
         Check_Fully_Conformant (New_S, Rename_Spec);
         Set_Public_Status (New_S);

         -- Indicate that the entity in the declaration functions like the
         -- corresponding body, and is not a new entity. The body will be
         -- constructed later at the freeze point, so indicate that the
         -- completion has not been seen yet.

         Set_Ekind (New_S, E_Subprogram_Body);
         New_S := Rename_Spec;
         Set_Has_Completion (Rename_Spec, False);

         -- Ada 2005: check overriding indicator

         if Must_Override (Specification (N))
           and then not Is_Overriding_Operation (Rename_Spec)
         then
            Error_Msg_NE ("subprogram& is not overriding", N, Rename_Spec);

         elsif Must_Not_Override (Specification (N))
           and then Is_Overriding_Operation (Rename_Spec)
         then
            Error_Msg_NE
              ("subprogram& overrides inherited operation", N, Rename_Spec);
         end if;

      else
         Generate_Definition (New_S);
         New_Overloaded_Entity (New_S);

         if Is_Entity_Name (Nam)
           and then Is_Intrinsic_Subprogram (Entity (Nam))
         then
            null;
         else
            Check_Delayed_Subprogram (New_S);
         end if;
      end if;

      -- There is no need for elaboration checks on the new entity, which may
      -- be called before the next freezing point where the body will appear.
      -- Elaboration checks refer to the real entity, not the one created by
      -- the renaming declaration.

      Set_Kill_Elaboration_Checks (New_S, True);

      if Etype (Nam) = Any_Type then
         Set_Has_Completion (New_S);
         return;

      elsif Nkind (Nam) = N_Selected_Component then

         -- Renamed entity is an entry or protected subprogram. For those
         -- cases an explicit body is built (at the point of freezing of this
         -- entity) that contains a call to the renamed entity.

         Analyze_Renamed_Entry (N, New_S, Present (Rename_Spec));
         return;

      elsif Nkind (Nam) = N_Explicit_Dereference then

         -- Renamed entity is designated by access_to_subprogram expression.
         -- Must build body to encapsulate call, as in the entry case.

         Analyze_Renamed_Dereference (N, New_S, Present (Rename_Spec));
         return;

      elsif Nkind (Nam) = N_Indexed_Component then
         Analyze_Renamed_Family_Member (N, New_S, Present (Rename_Spec));
         return;

      elsif Nkind (Nam) = N_Character_Literal then
         Analyze_Renamed_Character (N, New_S, Present (Rename_Spec));
         return;

      elsif (not Is_Entity_Name (Nam)
              and then Nkind (Nam) /= N_Operator_Symbol)
        or else not Is_Overloadable (Entity (Nam))
      then
         Error_Msg_N ("expect valid subprogram name in renaming", N);
         return;

      end if;

      -- Most common case: subprogram renames subprogram. No body is generated
      -- in this case, so we must indicate the declaration is complete as is.

      if No (Rename_Spec) then
         Set_Has_Completion (New_S);
      end if;

      -- Find the renamed entity that matches the given specification. Disable
      -- Ada_83 because there is no requirement of full conformance between
      -- renamed entity and new entity, even though the same circuit is used.

      -- This is a bit of a kludge, which introduces a really irregular use of
      -- Ada_Version[_Explicit]. Would be nice to find cleaner way to do this
      -- ???

      Ada_Version := Ada_Version_Type'Max (Ada_Version, Ada_95);
      Ada_Version_Explicit := Ada_Version;

      if No (Old_S) then
         Old_S := Find_Renamed_Entity (N, Name (N), New_S, Is_Actual);
      end if;

      if Old_S /= Any_Id then
         if Is_Actual
           and then From_Default (N)
         then
            -- This is an implicit reference to the default actual

            Generate_Reference (Old_S, Nam, Typ => 'i', Force => True);
         else
            Generate_Reference (Old_S, Nam);
         end if;

         -- For a renaming-as-body, require subtype conformance, but if the
         -- declaration being completed has not been frozen, then inherit the
         -- convention of the renamed subprogram prior to checking conformance
         -- (unless the renaming has an explicit convention established; the
         -- rule stated in the RM doesn't seem to address this ???).

         if Present (Rename_Spec) then
            Generate_Reference (Rename_Spec, Defining_Entity (Spec), 'b');
            Style.Check_Identifier (Defining_Entity (Spec), Rename_Spec);

            if not Is_Frozen (Rename_Spec) then
               if not Has_Convention_Pragma (Rename_Spec) then
                  Set_Convention (New_S, Convention (Old_S));
               end if;

               if Ekind (Old_S) /= E_Operator then
                  Check_Mode_Conformant (New_S, Old_S, Spec);
               end if;

               if Original_Subprogram (Old_S) = Rename_Spec then
                  Error_Msg_N ("unfrozen subprogram cannot rename itself ", N);
               end if;
            else
               Check_Subtype_Conformant (New_S, Old_S, Spec);
            end if;

            Check_Frozen_Renaming (N, Rename_Spec);

            -- Check explicitly that renamed entity is not intrinsic, because
            -- in in a generic the renamed body is not built. In this case,
            -- the renaming_as_body is a completion.

            if Inside_A_Generic then
               if Is_Frozen (Rename_Spec)
                 and then Is_Intrinsic_Subprogram (Old_S)
               then
                  Error_Msg_N
                    ("subprogram in renaming_as_body cannot be intrinsic",
                       Name (N));
               end if;

               Set_Has_Completion (Rename_Spec);
            end if;

         elsif Ekind (Old_S) /= E_Operator then
            Check_Mode_Conformant (New_S, Old_S);

            if Is_Actual
              and then Error_Posted (New_S)
            then
               Error_Msg_NE ("invalid actual subprogram: & #!", N, Old_S);
            end if;
         end if;

         if No (Rename_Spec) then

            -- The parameter profile of the new entity is that of the renamed
            -- entity: the subtypes given in the specification are irrelevant.

            Inherit_Renamed_Profile (New_S, Old_S);

            -- A call to the subprogram is transformed into a call to the
            -- renamed entity. This is transitive if the renamed entity is
            -- itself a renaming.

            if Present (Alias (Old_S)) then
               Set_Alias (New_S, Alias (Old_S));
            else
               Set_Alias (New_S, Old_S);
            end if;

            -- Note that we do not set Is_Intrinsic_Subprogram if we have a
            -- renaming as body, since the entity in this case is not an
            -- intrinsic (it calls an intrinsic, but we have a real body for
            -- this call, and it is in this body that the required intrinsic
            -- processing will take place).

            -- Also, if this is a renaming of inequality, the renamed operator
            -- is intrinsic, but what matters is the corresponding equality
            -- operator, which may be user-defined.

            Set_Is_Intrinsic_Subprogram
              (New_S,
                Is_Intrinsic_Subprogram (Old_S)
                  and then
                    (Chars (Old_S) /= Name_Op_Ne
                       or else Ekind (Old_S) = E_Operator
                       or else
                         Is_Intrinsic_Subprogram
                            (Corresponding_Equality (Old_S))));

            if Ekind (Alias (New_S)) = E_Operator then
               Set_Has_Delayed_Freeze (New_S, False);
            end if;

            -- If the renaming corresponds to an association for an abstract
            -- formal subprogram, then various attributes must be set to
            -- indicate that the renaming is an abstract dispatching operation
            -- with a controlling type.

            if Is_Actual and then Is_Abstract (Formal_Spec) then
               -- Mark the renaming as abstract here, so Find_Dispatching_Type
               -- see it as corresponding to a generic association for a
               -- formal abstract subprogram

               Set_Is_Abstract (New_S);

               declare
                  New_S_Ctrl_Type : constant Entity_Id :=
                                      Find_Dispatching_Type (New_S);
                  Old_S_Ctrl_Type : constant Entity_Id :=
                                      Find_Dispatching_Type (Old_S);

               begin
                  if Old_S_Ctrl_Type /= New_S_Ctrl_Type then
                     Error_Msg_NE
                       ("actual must be dispatching subprogram for type&",
                        Nam, New_S_Ctrl_Type);

                  else
                     Set_Is_Dispatching_Operation (New_S);
                     Check_Controlling_Formals (New_S_Ctrl_Type, New_S);

                     -- In the case where the actual in the formal subprogram
                     -- is itself a formal abstract subprogram association,
                     -- there's no dispatch table component or position to
                     -- inherit.

                     if Present (DTC_Entity (Old_S)) then
                        Set_DTC_Entity (New_S, DTC_Entity (Old_S));
                        Set_DT_Position (New_S, DT_Position (Old_S));
                     end if;
                  end if;
               end;
            end if;
         end if;

         if not Is_Actual
           and then (Old_S = New_S
                      or else (Nkind (Nam) /= N_Expanded_Name
                        and then Chars (Old_S) = Chars (New_S)))
         then
            Error_Msg_N ("subprogram cannot rename itself", N);
         end if;

         Set_Convention (New_S, Convention (Old_S));
         Set_Is_Abstract (New_S, Is_Abstract (Old_S));
         Check_Library_Unit_Renaming (N, Old_S);

         -- Pathological case: procedure renames entry in the scope of its
         -- task. Entry is given by simple name, but body must be built for
         -- procedure. Of course if called it will deadlock.

         if Ekind (Old_S) = E_Entry then
            Set_Has_Completion (New_S, False);
            Set_Alias (New_S, Empty);
         end if;

         if Is_Actual then
            Freeze_Before (N, Old_S);
            Set_Has_Delayed_Freeze (New_S, False);
            Freeze_Before (N, New_S);

            -- An abstract subprogram is only allowed as an actual in the case
            -- where the formal subprogram is also abstract.

            if (Ekind (Old_S) = E_Procedure or else Ekind (Old_S) = E_Function)
              and then Is_Abstract (Old_S)
              and then not Is_Abstract (Formal_Spec)
            then
               Error_Msg_N
                 ("abstract subprogram not allowed as generic actual", Nam);
            end if;
         end if;

      else
         -- A common error is to assume that implicit operators for types are
         -- defined in Standard, or in the scope of a subtype. In those cases
         -- where the renamed entity is given with an expanded name, it is
         -- worth mentioning that operators for the type are not declared in
         -- the scope given by the prefix.

         if Nkind (Nam) = N_Expanded_Name
           and then Nkind (Selector_Name (Nam)) = N_Operator_Symbol
           and then Scope (Entity (Nam)) = Standard_Standard
         then
            declare
               T : constant Entity_Id :=
                     Base_Type (Etype (First_Formal (New_S)));

            begin
               Error_Msg_Node_2 := Prefix (Nam);
               Error_Msg_NE
                 ("operator for type& is not declared in&", Prefix (Nam), T);
            end;

         else
            Error_Msg_NE
              ("no visible subprogram matches the specification for&",
                Spec, New_S);
         end if;

         if Present (Candidate_Renaming) then
            declare
               F1 : Entity_Id;
               F2 : Entity_Id;

            begin
               F1 := First_Formal (Candidate_Renaming);
               F2 := First_Formal (New_S);

               while Present (F1) and then Present (F2) loop
                  Next_Formal (F1);
                  Next_Formal (F2);
               end loop;

               if Present (F1) and then Present (Default_Value (F1)) then
                  if Present (Next_Formal (F1)) then
                     Error_Msg_NE
                       ("\missing specification for &" &
                          " and other formals with defaults", Spec, F1);
                  else
                     Error_Msg_NE
                    ("\missing specification for &", Spec, F1);
                  end if;
               end if;
            end;
         end if;
      end if;

      -- Ada 2005 AI 404: if the new subprogram is dispatching, verify that
      -- controlling access parameters are known non-null for the renamed
      -- subprogram. Test also applies to a subprogram instantiation that
      -- is dispatching.

      if Ada_Version >= Ada_05
        and then not Is_Dispatching_Operation (Old_S)
        and then Is_Dispatching_Operation (New_S)
      then
         declare
            Old_F : Entity_Id;
            New_F : Entity_Id;

         begin
            Old_F := First_Formal (Old_S);
            New_F := First_Formal (New_S);
            while Present (Old_F) loop
               if Ekind (Etype (Old_F)) = E_Anonymous_Access_Type
                 and then Is_Controlling_Formal (New_F)
                 and then not Can_Never_Be_Null (Old_F)
               then
                  Error_Msg_N ("access parameter is controlling,", New_F);
                  Error_Msg_NE ("\corresponding parameter of& " &
                    " must be explicitly null excluding", New_F, Old_S);
               end if;

               Next_Formal (Old_F);
               Next_Formal (New_F);
            end loop;
         end;
      end if;

      -- A useful warning, suggested by Ada Bug Finder (Ada-Europe 2005)

      if Comes_From_Source (N)
        and then Present (Old_S)
        and then Nkind (Old_S) = N_Defining_Operator_Symbol
        and then Nkind (New_S) = N_Defining_Operator_Symbol
        and then Chars (Old_S) /= Chars (New_S)
      then
         Error_Msg_NE
           ("?& is being renamed as a different operator",
             New_S, Old_S);
      end if;

      Ada_Version := Save_AV;
      Ada_Version_Explicit := Save_AV_Exp;
   end Analyze_Subprogram_Renaming;

   -------------------------
   -- Analyze_Use_Package --
   -------------------------

   -- Resolve the package names in the use clause, and make all the visible
   -- entities defined in the package potentially use-visible. If the package
   -- is already in use from a previous use clause, its visible entities are
   -- already use-visible. In that case, mark the occurrence as a redundant
   -- use. If the package is an open scope, i.e. if the use clause occurs
   -- within the package itself, ignore it.

   procedure Analyze_Use_Package (N : Node_Id) is
      Pack_Name : Node_Id;
      Pack : Entity_Id;

   -- Start of processing for Analyze_Use_Package

   begin
      Set_Hidden_By_Use_Clause (N, No_Elist);

      -- Use clause is not allowed in a spec of a predefined package
      -- declaration except that packages whose file name starts a-n are OK
      -- (these are children of Ada.Numerics, and such packages are never
      -- loaded by Rtsfind).

      if Is_Predefined_File_Name (Unit_File_Name (Current_Sem_Unit))
        and then Name_Buffer (1 .. 3) /= "a-n"
        and then
          Nkind (Unit (Cunit (Current_Sem_Unit))) = N_Package_Declaration
      then
         Error_Msg_N ("use clause not allowed in predefined spec", N);
      end if;

      -- Chain clause to list of use clauses in current scope

      if Nkind (Parent (N)) /= N_Compilation_Unit then
         Chain_Use_Clause (N);
      end if;

      -- Loop through package names to identify referenced packages

      Pack_Name := First (Names (N));

      while Present (Pack_Name) loop
         Analyze (Pack_Name);

         if Nkind (Parent (N)) = N_Compilation_Unit
           and then Nkind (Pack_Name) = N_Expanded_Name
         then
            declare
               Pref : Node_Id := Prefix (Pack_Name);

            begin
               while Nkind (Pref) = N_Expanded_Name loop
                  Pref := Prefix (Pref);
               end loop;

               if Entity (Pref) = Standard_Standard then
                  Error_Msg_N
                   ("predefined package Standard cannot appear"
                     & " in a context clause", Pref);
               end if;
            end;
         end if;

         Next (Pack_Name);
      end loop;

      -- Loop through package names to mark all entities as potentially
      -- use visible.

      Pack_Name := First (Names (N));

      while Present (Pack_Name) loop

         if Is_Entity_Name (Pack_Name) then
            Pack := Entity (Pack_Name);

            if Ekind (Pack) /= E_Package
              and then Etype (Pack) /= Any_Type
            then
               if Ekind (Pack) = E_Generic_Package then
                  Error_Msg_N
                   ("a generic package is not allowed in a use clause",
                      Pack_Name);
               else
                  Error_Msg_N ("& is not a usable package", Pack_Name);
               end if;

            else
               if Nkind (Parent (N)) = N_Compilation_Unit then
                  Check_In_Previous_With_Clause (N, Pack_Name);
               end if;

               if Applicable_Use (Pack_Name) then
                  Use_One_Package (Pack, N);
               end if;
            end if;
         end if;

         Next (Pack_Name);
      end loop;

   end Analyze_Use_Package;

   ----------------------
   -- Analyze_Use_Type --
   ----------------------

   procedure Analyze_Use_Type (N : Node_Id) is
      Id : Entity_Id;

   begin
      Set_Hidden_By_Use_Clause (N, No_Elist);

      -- Chain clause to list of use clauses in current scope

      if Nkind (Parent (N)) /= N_Compilation_Unit then
         Chain_Use_Clause (N);
      end if;

      Id := First (Subtype_Marks (N));

      while Present (Id) loop
         Find_Type (Id);

         if Entity (Id) /= Any_Type then
            Use_One_Type (Id);

            if Nkind (Parent (N)) = N_Compilation_Unit then
               if Nkind (Id) = N_Identifier then
                  Error_Msg_N ("type is not directly visible", Id);

               elsif Is_Child_Unit (Scope (Entity (Id)))
                 and then Scope (Entity (Id)) /= System_Aux_Id
               then
                  Check_In_Previous_With_Clause (N, Prefix (Id));
               end if;
            end if;
         end if;

         Next (Id);
      end loop;
   end Analyze_Use_Type;

   --------------------
   -- Applicable_Use --
   --------------------

   function Applicable_Use (Pack_Name : Node_Id) return Boolean is
      Pack : constant Entity_Id := Entity (Pack_Name);

   begin
      if In_Open_Scopes (Pack) then
         return False;

      elsif In_Use (Pack) then
         Note_Redundant_Use (Pack_Name);
         return False;

      elsif Present (Renamed_Object (Pack))
        and then In_Use (Renamed_Object (Pack))
      then
         Note_Redundant_Use (Pack_Name);
         return False;

      else
         return True;
      end if;
   end Applicable_Use;

   ------------------------
   -- Attribute_Renaming --
   ------------------------

   procedure Attribute_Renaming (N : Node_Id) is
      Loc : constant Source_Ptr := Sloc (N);
      Nam : constant Node_Id := Name (N);
      Spec : constant Node_Id := Specification (N);
      New_S : constant Entity_Id := Defining_Unit_Name (Spec);
      Aname : constant Name_Id := Attribute_Name (Nam);

      Form_Num : Nat := 0;
      Expr_List : List_Id := No_List;

      Attr_Node : Node_Id;
      Body_Node : Node_Id;
      Param_Spec : Node_Id;

   begin
      Generate_Definition (New_S);

      -- This procedure is called in the context of subprogram renaming,
      -- and thus the attribute must be one that is a subprogram. All of
      -- those have at least one formal parameter, with the singular
      -- exception of AST_Entry (which is a real oddity, it is odd that
      -- this can be renamed at all!)

      if not Is_Non_Empty_List (Parameter_Specifications (Spec)) then
         if Aname /= Name_AST_Entry then
            Error_Msg_N
              ("subprogram renaming an attribute must have formals", N);
            return;
         end if;

      else
         Param_Spec := First (Parameter_Specifications (Spec));

         while Present (Param_Spec) loop
            Form_Num := Form_Num + 1;

            if Nkind (Parameter_Type (Param_Spec)) /= N_Access_Definition then
               Find_Type (Parameter_Type (Param_Spec));

               -- The profile of the new entity denotes the base type (s) of
               -- the types given in the specification. For access parameters
               -- there are no subtypes involved.

               Rewrite (Parameter_Type (Param_Spec),
                New_Reference_To
                  (Base_Type (Entity (Parameter_Type (Param_Spec))), Loc));
            end if;

            if No (Expr_List) then
               Expr_List := New_List;
            end if;

            Append_To (Expr_List,
              Make_Identifier (Loc,
                Chars => Chars (Defining_Identifier (Param_Spec))));

            -- The expressions in the attribute reference are not freeze
            -- points. Neither is the attribute as a whole, see below.

            Set_Must_Not_Freeze (Last (Expr_List));
            Next (Param_Spec);
         end loop;
      end if;

      -- Immediate error if too many formals. Other mismatches in numbers
      -- of number of types of parameters are detected when we analyze the
      -- body of the subprogram that we construct.

      if Form_Num > 2 then
         Error_Msg_N ("too many formals for attribute", N);

      -- Error if the attribute reference has expressions that look
      -- like formal parameters.

      elsif Present (Expressions (Nam)) then
         Error_Msg_N ("illegal expressions in attribute reference", Nam);

      elsif
        Aname = Name_Compose or else
        Aname = Name_Exponent or else
        Aname = Name_Leading_Part or else
        Aname = Name_Pos or else
        Aname = Name_Round or else
        Aname = Name_Scaling or else
        Aname = Name_Val
      then
         if Nkind (N) = N_Subprogram_Renaming_Declaration
           and then Present (Corresponding_Formal_Spec (N))
         then
            Error_Msg_N
              ("generic actual cannot be attribute involving universal type",
               Nam);
         else
            Error_Msg_N
              ("attribute involving a universal type cannot be renamed",
               Nam);
         end if;
      end if;

      -- AST_Entry is an odd case. It doesn't really make much sense to
      -- allow it to be renamed, but that's the DEC rule, so we have to
      -- do it right. The point is that the AST_Entry call should be made
      -- now, and what the function will return is the returned value.

      -- Note that there is no Expr_List in this case anyway

      if Aname = Name_AST_Entry then

         declare
            Ent : Entity_Id;
            Decl : Node_Id;

         begin
            Ent := Make_Defining_Identifier (Loc, New_Internal_Name ('R'));

            Decl :=
              Make_Object_Declaration (Loc,
                Defining_Identifier => Ent,
                Object_Definition =>
                  New_Occurrence_Of (RTE (RE_AST_Handler), Loc),
                Expression => Nam,
                Constant_Present => True);

            Set_Assignment_OK (Decl, True);
            Insert_Action (N, Decl);
            Attr_Node := Make_Identifier (Loc, Chars (Ent));
         end;

      -- For all other attributes, we rewrite the attribute node to have
      -- a list of expressions corresponding to the subprogram formals.
      -- A renaming declaration is not a freeze point, and the analysis of
      -- the attribute reference should not freeze the type of the prefix.

      else
         Attr_Node :=
           Make_Attribute_Reference (Loc,
             Prefix => Prefix (Nam),
             Attribute_Name => Aname,
             Expressions => Expr_List);

         Set_Must_Not_Freeze (Attr_Node);
         Set_Must_Not_Freeze (Prefix (Nam));
      end if;

      -- Case of renaming a function

      if Nkind (Spec) = N_Function_Specification then

         if Is_Procedure_Attribute_Name (Aname) then
            Error_Msg_N ("attribute can only be renamed as procedure", Nam);
            return;
         end if;

         Find_Type (Result_Definition (Spec));
         Rewrite (Result_Definition (Spec),
             New_Reference_To (
               Base_Type (Entity (Result_Definition (Spec))), Loc));

         Body_Node :=
           Make_Subprogram_Body (Loc,
             Specification => Spec,
             Declarations => New_List,
             Handled_Statement_Sequence =>
               Make_Handled_Sequence_Of_Statements (Loc,
                   Statements => New_List (
                     Make_Return_Statement (Loc,
                       Expression => Attr_Node))));

      -- Case of renaming a procedure

      else
         if not Is_Procedure_Attribute_Name (Aname) then
            Error_Msg_N ("attribute can only be renamed as function", Nam);
            return;
         end if;

         Body_Node :=
           Make_Subprogram_Body (Loc,
             Specification => Spec,
             Declarations => New_List,
             Handled_Statement_Sequence =>
               Make_Handled_Sequence_Of_Statements (Loc,
                   Statements => New_List (Attr_Node)));
      end if;

      Rewrite (N, Body_Node);
      Analyze (N);

      if Is_Compilation_Unit (New_S) then
         Error_Msg_N
           ("a library unit can only rename another library unit", N);
      end if;

      Set_Etype (New_S, Base_Type (Etype (New_S)));

      -- We suppress elaboration warnings for the resulting entity, since
      -- clearly they are not needed, and more particularly, in the case
      -- of a generic formal subprogram, the resulting entity can appear
      -- after the instantiation itself, and thus look like a bogus case
      -- of access before elaboration.

      Set_Suppress_Elaboration_Warnings (New_S);

   end Attribute_Renaming;

   ----------------------
   -- Chain_Use_Clause --
   ----------------------

   procedure Chain_Use_Clause (N : Node_Id) is
      Pack : Entity_Id;
      Level : Int := Scope_Stack.Last;

   begin
      if not Is_Compilation_Unit (Current_Scope)
        or else not Is_Child_Unit (Current_Scope)
      then
         null; -- Common case

      elsif Defining_Entity (Parent (N)) = Current_Scope then
         null; -- Common case for compilation unit

      else
         -- If declaration appears in some other scope, it must be in some
         -- parent unit when compiling a child.

         Pack := Defining_Entity (Parent (N));
         if not In_Open_Scopes (Pack) then
            null; -- default as well

         else
            -- Find entry for parent unit in scope stack

            while Scope_Stack.Table (Level).Entity /= Pack loop
               Level := Level - 1;
            end loop;
         end if;
      end if;

      Set_Next_Use_Clause (N,
        Scope_Stack.Table (Level).First_Use_Clause);
      Scope_Stack.Table (Level).First_Use_Clause := N;
   end Chain_Use_Clause;

   ---------------------------
   -- Check_Frozen_Renaming --
   ---------------------------

   procedure Check_Frozen_Renaming (N : Node_Id; Subp : Entity_Id) is
      B_Node : Node_Id;
      Old_S : Entity_Id;

   begin
      if Is_Frozen (Subp)
        and then not Has_Completion (Subp)
      then
         B_Node :=
           Build_Renamed_Body
             (Parent (Declaration_Node (Subp)), Defining_Entity (N));

         if Is_Entity_Name (Name (N)) then
            Old_S := Entity (Name (N));

            if not Is_Frozen (Old_S)
              and then Operating_Mode /= Check_Semantics
            then
               Append_Freeze_Action (Old_S, B_Node);
            else
               Insert_After (N, B_Node);
               Analyze (B_Node);
            end if;

            if Is_Intrinsic_Subprogram (Old_S)
              and then not In_Instance
            then
               Error_Msg_N
                 ("subprogram used in renaming_as_body cannot be intrinsic",
                    Name (N));
            end if;

         else
            Insert_After (N, B_Node);
            Analyze (B_Node);
         end if;
      end if;
   end Check_Frozen_Renaming;

   -----------------------------------
   -- Check_In_Previous_With_Clause --
   -----------------------------------

   procedure Check_In_Previous_With_Clause
     (N : Node_Id;
      Nam : Entity_Id)
   is
      Pack : constant Entity_Id := Entity (Original_Node (Nam));
      Item : Node_Id;
      Par : Node_Id;

   begin
      Item := First (Context_Items (Parent (N)));

      while Present (Item)
        and then Item /= N
      loop
         if Nkind (Item) = N_With_Clause

            -- Protect the frontend against previously reported
            -- critical errors

           and then Nkind (Name (Item)) /= N_Selected_Component
           and then Entity (Name (Item)) = Pack
         then
            Par := Nam;

            -- Find root library unit in with_clause

            while Nkind (Par) = N_Expanded_Name loop
               Par := Prefix (Par);
            end loop;

            if Is_Child_Unit (Entity (Original_Node (Par))) then
               Error_Msg_NE
                 ("& is not directly visible", Par, Entity (Par));
            else
               return;
            end if;
         end if;

         Next (Item);
      end loop;

      -- On exit, package is not mentioned in a previous with_clause.
      -- Check if its prefix is.

      if Nkind (Nam) = N_Expanded_Name then
         Check_In_Previous_With_Clause (N, Prefix (Nam));

      elsif Pack /= Any_Id then
         Error_Msg_NE ("& is not visible", Nam, Pack);
      end if;
   end Check_In_Previous_With_Clause;

   ---------------------------------
   -- Check_Library_Unit_Renaming --
   ---------------------------------

   procedure Check_Library_Unit_Renaming (N : Node_Id; Old_E : Entity_Id) is
      New_E : Entity_Id;

   begin
      if Nkind (Parent (N)) /= N_Compilation_Unit then
         return;

      elsif Scope (Old_E) /= Standard_Standard
        and then not Is_Child_Unit (Old_E)
      then
         Error_Msg_N ("renamed unit must be a library unit", Name (N));

      -- Entities defined in Standard (operators and boolean literals) cannot
      -- be renamed as library units.

      elsif Scope (Old_E) = Standard_Standard
        and then Sloc (Old_E) = Standard_Location
      then
         Error_Msg_N ("renamed unit must be a library unit", Name (N));

      elsif Present (Parent_Spec (N))
        and then Nkind (Unit (Parent_Spec (N))) = N_Generic_Package_Declaration
        and then not Is_Child_Unit (Old_E)
      then
         Error_Msg_N
           ("renamed unit must be a child unit of generic parent", Name (N));

      elsif Nkind (N) in N_Generic_Renaming_Declaration
         and then Nkind (Name (N)) = N_Expanded_Name
         and then Is_Generic_Instance (Entity (Prefix (Name (N))))
         and then Is_Generic_Unit (Old_E)
      then
         Error_Msg_N
           ("renamed generic unit must be a library unit", Name (N));

      elsif Ekind (Old_E) = E_Package
        or else Ekind (Old_E) = E_Generic_Package
      then
         -- Inherit categorization flags

         New_E := Defining_Entity (N);
         Set_Is_Pure (New_E, Is_Pure (Old_E));
         Set_Is_Preelaborated (New_E, Is_Preelaborated (Old_E));
         Set_Is_Remote_Call_Interface (New_E,
                                       Is_Remote_Call_Interface (Old_E));
         Set_Is_Remote_Types (New_E, Is_Remote_Types (Old_E));
         Set_Is_Shared_Passive (New_E, Is_Shared_Passive (Old_E));
      end if;
   end Check_Library_Unit_Renaming;

   ---------------
   -- End_Scope --
   ---------------

   procedure End_Scope is
      Id : Entity_Id;
      Prev : Entity_Id;
      Outer : Entity_Id;

   begin
      Id := First_Entity (Current_Scope);

      while Present (Id) loop
         -- An entity in the current scope is not necessarily the first one
         -- on its homonym chain. Find its predecessor if any,
         -- If it is an internal entity, it will not be in the visibility
         -- chain altogether, and there is nothing to unchain.

         if Id /= Current_Entity (Id) then
            Prev := Current_Entity (Id);
            while Present (Prev)
              and then Present (Homonym (Prev))
              and then Homonym (Prev) /= Id
            loop
               Prev := Homonym (Prev);
            end loop;

            -- Skip to end of loop if Id is not in the visibility chain

            if No (Prev) or else Homonym (Prev) /= Id then
               goto Next_Ent;
            end if;

         else
            Prev := Empty;
         end if;

         Outer := Homonym (Id);
         Set_Is_Immediately_Visible (Id, False);

         while Present (Outer) and then Scope (Outer) = Current_Scope loop
            Outer := Homonym (Outer);
         end loop;

         -- Reset homonym link of other entities, but do not modify link
         -- between entities in current scope, so that the back-end can have
         -- a proper count of local overloadings.

         if No (Prev) then
            Set_Name_Entity_Id (Chars (Id), Outer);

         elsif Scope (Prev) /= Scope (Id) then
            Set_Homonym (Prev, Outer);
         end if;

         <<Next_Ent>>
            Next_Entity (Id);
      end loop;

      -- If the scope generated freeze actions, place them before the
      -- current declaration and analyze them. Type declarations and
      -- the bodies of initialization procedures can generate such nodes.
      -- We follow the parent chain until we reach a list node, which is
      -- the enclosing list of declarations. If the list appears within
      -- a protected definition, move freeze nodes outside the protected
      -- type altogether.

      if Present
         (Scope_Stack.Table (Scope_Stack.Last).Pending_Freeze_Actions)
      then
         declare
            Decl : Node_Id;
            L : constant List_Id := Scope_Stack.Table
                    (Scope_Stack.Last).Pending_Freeze_Actions;

         begin
            if Is_Itype (Current_Scope) then
               Decl := Associated_Node_For_Itype (Current_Scope);
            else
               Decl := Parent (Current_Scope);
            end if;

            Pop_Scope;

            while not (Is_List_Member (Decl))
              or else Nkind (Parent (Decl)) = N_Protected_Definition
              or else Nkind (Parent (Decl)) = N_Task_Definition
            loop
               Decl := Parent (Decl);
            end loop;

            Insert_List_Before_And_Analyze (Decl, L);
         end;

      else
         Pop_Scope;
      end if;

   end End_Scope;

   ---------------------
   -- End_Use_Clauses --
   ---------------------

   procedure End_Use_Clauses (Clause : Node_Id) is
      U : Node_Id;

   begin
      -- Remove Use_Type clauses first, because they affect the
      -- visibility of operators in subsequent used packages.

      U := Clause;
      while Present (U) loop
         if Nkind (U) = N_Use_Type_Clause then
            End_Use_Type (U);
         end if;

         Next_Use_Clause (U);
      end loop;

      U := Clause;
      while Present (U) loop
         if Nkind (U) = N_Use_Package_Clause then
            End_Use_Package (U);
         end if;

         Next_Use_Clause (U);
      end loop;
   end End_Use_Clauses;

   ---------------------
   -- End_Use_Package --
   ---------------------

   procedure End_Use_Package (N : Node_Id) is
      Pack_Name : Node_Id;
      Pack : Entity_Id;
      Id : Entity_Id;
      Elmt : Elmt_Id;

      function Is_Primitive_Operator
        (Op : Entity_Id;
         F : Entity_Id) return Boolean;
      -- Check whether Op is a primitive operator of a use-visible type

      ---------------------------
      -- Is_Primitive_Operator --
      ---------------------------

      function Is_Primitive_Operator
        (Op : Entity_Id;
         F : Entity_Id) return Boolean
      is
         T : constant Entity_Id := Etype (F);

      begin
         return In_Use (T)
           and then Scope (T) = Scope (Op);
      end Is_Primitive_Operator;

   -- Start of processing for End_Use_Package

   begin
      Pack_Name := First (Names (N));

      while Present (Pack_Name) loop
         Pack := Entity (Pack_Name);

         if Ekind (Pack) = E_Package then

            if In_Open_Scopes (Pack) then
               null;

            elsif not Redundant_Use (Pack_Name) then
               Set_In_Use (Pack, False);
               Set_Current_Use_Clause (Pack, Empty);
               Id := First_Entity (Pack);

               while Present (Id) loop

                  -- Preserve use-visibility of operators that are primitive
                  -- operators of a type that is use_visible through an active
                  -- use_type clause.

                  if Nkind (Id) = N_Defining_Operator_Symbol
                       and then
                         (Is_Primitive_Operator (Id, First_Formal (Id))
                            or else
                          (Present (Next_Formal (First_Formal (Id)))
                             and then
                               Is_Primitive_Operator
                                 (Id, Next_Formal (First_Formal (Id)))))
                  then
                     null;

                  else
                     Set_Is_Potentially_Use_Visible (Id, False);
                  end if;

                  if Is_Private_Type (Id)
                    and then Present (Full_View (Id))
                  then
                     Set_Is_Potentially_Use_Visible (Full_View (Id), False);
                  end if;

                  Next_Entity (Id);
               end loop;

               if Present (Renamed_Object (Pack)) then
                  Set_In_Use (Renamed_Object (Pack), False);
                  Set_Current_Use_Clause (Renamed_Object (Pack), Empty);
               end if;

               if Chars (Pack) = Name_System
                 and then Scope (Pack) = Standard_Standard
                 and then Present_System_Aux
               then
                  Id := First_Entity (System_Aux_Id);

                  while Present (Id) loop
                     Set_Is_Potentially_Use_Visible (Id, False);

                     if Is_Private_Type (Id)
                       and then Present (Full_View (Id))
                     then
                        Set_Is_Potentially_Use_Visible (Full_View (Id), False);
                     end if;

                     Next_Entity (Id);
                  end loop;

                  Set_In_Use (System_Aux_Id, False);
               end if;

            else
               Set_Redundant_Use (Pack_Name, False);
            end if;

         end if;

         Next (Pack_Name);
      end loop;

      if Present (Hidden_By_Use_Clause (N)) then
         Elmt := First_Elmt (Hidden_By_Use_Clause (N));

         while Present (Elmt) loop
            Set_Is_Immediately_Visible (Node (Elmt));
            Next_Elmt (Elmt);
         end loop;

         Set_Hidden_By_Use_Clause (N, No_Elist);
      end if;
   end End_Use_Package;

   ------------------
   -- End_Use_Type --
   ------------------

   procedure End_Use_Type (N : Node_Id) is
      Id : Entity_Id;
      Op_List : Elist_Id;
      Elmt : Elmt_Id;
      T : Entity_Id;

   begin
      Id := First (Subtype_Marks (N));

      while Present (Id) loop

         -- A call to rtsfind may occur while analyzing a use_type clause,
         -- in which case the type marks are not resolved yet, and there is
         -- nothing to remove.

         if not Is_Entity_Name (Id)
           or else No (Entity (Id))
         then
            goto Continue;
         end if;

         T := Entity (Id);

         if T = Any_Type then
            null;

         -- Note that the use_Type clause may mention a subtype of the
         -- type whose primitive operations have been made visible. Here
         -- as elsewhere, it is the base type that matters for visibility.

         elsif In_Open_Scopes (Scope (Base_Type (T))) then
            null;

         elsif not Redundant_Use (Id) then
            Set_In_Use (T, False);
            Set_In_Use (Base_Type (T), False);
            Op_List := Collect_Primitive_Operations (T);
            Elmt := First_Elmt (Op_List);

            while Present (Elmt) loop

               if Nkind (Node (Elmt)) = N_Defining_Operator_Symbol then
                  Set_Is_Potentially_Use_Visible (Node (Elmt), False);
               end if;

               Next_Elmt (Elmt);
            end loop;
         end if;

         <<Continue>>
         Next (Id);
      end loop;
   end End_Use_Type;

   ----------------------
   -- Find_Direct_Name --
   ----------------------

   procedure Find_Direct_Name (N : Node_Id) is
      E : Entity_Id;
      E2 : Entity_Id;
      Msg : Boolean;

      Inst : Entity_Id := Empty;
      -- Enclosing instance, if any

      Homonyms : Entity_Id;
      -- Saves start of homonym chain

      Nvis_Entity : Boolean;
      -- Set True to indicate that at there is at least one entity on the
      -- homonym chain which, while not visible, is visible enough from the
      -- user point of view to warrant an error message of "not visible"
      -- rather than undefined.

      Nvis_Is_Private_Subprg : Boolean := False;
      -- Ada 2005 (AI-262): Set True to indicate that a form of Beaujolais
      -- effect concerning library subprograms has been detected. Used to
      -- generate the precise error message.

      function From_Actual_Package (E : Entity_Id) return Boolean;
      -- Returns true if the entity is declared in a package that is
      -- an actual for a formal package of the current instance. Such an
      -- entity requires special handling because it may be use-visible
      -- but hides directly visible entities defined outside the instance.

      function Known_But_Invisible (E : Entity_Id) return Boolean;
      -- This function determines whether the entity E (which is not
      -- visible) can reasonably be considered to be known to the writer
      -- of the reference. This is a heuristic test, used only for the
      -- purposes of figuring out whether we prefer to complain that an
      -- entity is undefined or invisible (and identify the declaration
      -- of the invisible entity in the latter case). The point here is
      -- that we don't want to complain that something is invisible and
      -- then point to something entirely mysterious to the writer.

      procedure Nvis_Messages;
      -- Called if there are no visible entries for N, but there is at least
      -- one non-directly visible, or hidden declaration. This procedure
      -- outputs an appropriate set of error messages.

      procedure Undefined (Nvis : Boolean);
      -- This function is called if the current node has no corresponding
      -- visible entity or entities. The value set in Msg indicates whether
      -- an error message was generated (multiple error messages for the
      -- same variable are generally suppressed, see body for details).
      -- Msg is True if an error message was generated, False if not. This
      -- value is used by the caller to determine whether or not to output
      -- additional messages where appropriate. The parameter is set False
      -- to get the message "X is undefined", and True to get the message
      -- "X is not visible".

      -------------------------
      -- From_Actual_Package --
      -------------------------

      function From_Actual_Package (E : Entity_Id) return Boolean is
         Scop : constant Entity_Id := Scope (E);
         Act : Entity_Id;

      begin
         if not In_Instance then
            return False;
         else
            Inst := Current_Scope;

            while Present (Inst)
              and then Ekind (Inst) /= E_Package
              and then not Is_Generic_Instance (Inst)
            loop
               Inst := Scope (Inst);
            end loop;

            if No (Inst) then
               return False;
            end if;

            Act := First_Entity (Inst);

            while Present (Act) loop
               if Ekind (Act) = E_Package then

                  -- Check for end of actuals list

                  if Renamed_Object (Act) = Inst then
                     return False;

                  elsif Present (Associated_Formal_Package (Act))
                    and then Renamed_Object (Act) = Scop
                  then
                     -- Entity comes from (instance of) formal package

                     return True;

                  else
                     Next_Entity (Act);
                  end if;

               else
                  Next_Entity (Act);
               end if;
            end loop;

            return False;
         end if;
      end From_Actual_Package;

      -------------------------
      -- Known_But_Invisible --
      -------------------------

      function Known_But_Invisible (E : Entity_Id) return Boolean is
         Fname : File_Name_Type;

      begin
         -- Entities in Standard are always considered to be known

         if Sloc (E) <= Standard_Location then
            return True;

         -- An entity that does not come from source is always considered
         -- to be unknown, since it is an artifact of code expansion.

         elsif not Comes_From_Source (E) then
            return False;

         -- In gnat internal mode, we consider all entities known

         elsif GNAT_Mode then
            return True;
         end if;

         -- Here we have an entity that is not from package Standard, and
         -- which comes from Source. See if it comes from an internal file.

         Fname := Unit_File_Name (Get_Source_Unit (E));

         -- Case of from internal file

         if Is_Internal_File_Name (Fname) then

            -- Private part entities in internal files are never considered
            -- to be known to the writer of normal application code.

            if Is_Hidden (E) then
               return False;
            end if;

            -- Entities from System packages other than System and
            -- System.Storage_Elements are not considered to be known.
            -- System.Auxxxx files are also considered known to the user.

            -- Should refine this at some point to generally distinguish
            -- between known and unknown internal files ???

            Get_Name_String (Fname);

            return
              Name_Len < 2
                or else
              Name_Buffer (1 .. 2) /= "s-"
                or else
              Name_Buffer (3 .. 8) = "stoele"
                or else
              Name_Buffer (3 .. 5) = "aux";

         -- If not an internal file, then entity is definitely known,
         -- even if it is in a private part (the message generated will
         -- note that it is in a private part)

         else
            return True;
         end if;
      end Known_But_Invisible;

      -------------------
      -- Nvis_Messages --
      -------------------

      procedure Nvis_Messages is
         Comp_Unit : Node_Id;
         Ent : Entity_Id;
         Hidden : Boolean := False;
         Item : Node_Id;

      begin
         -- Ada 2005 (AI-262): Generate a precise error concerning the
         -- Beaujolais effect that was previously detected

         if Nvis_Is_Private_Subprg then

            pragma Assert (Nkind (E2) = N_Defining_Identifier
                           and then Ekind (E2) = E_Function
                           and then Scope (E2) = Standard_Standard
                           and then Has_Private_With (E2));

            -- Find the sloc corresponding to the private with'ed unit

            Comp_Unit := Cunit (Current_Sem_Unit);
            Item := First (Context_Items (Comp_Unit));
            Error_Msg_Sloc := No_Location;

            while Present (Item) loop
               if Nkind (Item) = N_With_Clause
                 and then Private_Present (Item)
                 and then Entity (Name (Item)) = E2
               then
                  Error_Msg_Sloc := Sloc (Item);
                  exit;
               end if;

               Next (Item);
            end loop;

            pragma Assert (Error_Msg_Sloc /= No_Location);

            Error_Msg_N ("(Ada 2005): hidden by private with clause #", N);
            return;
         end if;

         Undefined (Nvis => True);

         if Msg then

            -- First loop does hidden declarations

            Ent := Homonyms;
            while Present (Ent) loop
               if Is_Potentially_Use_Visible (Ent) then

                  if not Hidden then
                     Error_Msg_N ("multiple use clauses cause hiding!", N);
                     Hidden := True;
                  end if;

                  Error_Msg_Sloc := Sloc (Ent);
                  Error_Msg_N ("hidden declaration#!", N);
               end if;

               Ent := Homonym (Ent);
            end loop;

            -- If we found hidden declarations, then that's enough, don't
            -- bother looking for non-visible declarations as well.

            if Hidden then
               return;
            end if;

            -- Second loop does non-directly visible declarations

            Ent := Homonyms;
            while Present (Ent) loop
               if not Is_Potentially_Use_Visible (Ent) then

                  -- Do not bother the user with unknown entities

                  if not Known_But_Invisible (Ent) then
                     goto Continue;
                  end if;

                  Error_Msg_Sloc := Sloc (Ent);

                  -- Output message noting that there is a non-visible
                  -- declaration, distinguishing the private part case.

                  if Is_Hidden (Ent) then
                     Error_Msg_N ("non-visible (private) declaration#!", N);
                  else
                     Error_Msg_N ("non-visible declaration#!", N);

                     if Is_Compilation_Unit (Ent)
                       and then
                         Nkind (Parent (Parent (N))) = N_Use_Package_Clause
                     then
                        Error_Msg_NE
                         ("\possibly missing with_clause for&", N, Ent);
                     end if;
                  end if;

                  -- Set entity and its containing package as referenced. We
                  -- can't be sure of this, but this seems a better choice
                  -- to avoid unused entity messages.

                  if Comes_From_Source (Ent) then
                     Set_Referenced (Ent);
                     Set_Referenced (Cunit_Entity (Get_Source_Unit (Ent)));
                  end if;
               end if;

               <<Continue>>
               Ent := Homonym (Ent);
            end loop;

         end if;
      end Nvis_Messages;

      ---------------
      -- Undefined --
      ---------------

      procedure Undefined (Nvis : Boolean) is
         Emsg : Error_Msg_Id;

      begin
         -- We should never find an undefined internal name. If we do, then
         -- see if we have previous errors. If so, ignore on the grounds that
         -- it is probably a cascaded message (e.g. a block label from a badly
         -- formed block). If no previous errors, then we have a real internal
         -- error of some kind so raise an exception.

         if Is_Internal_Name (Chars (N)) then
            if Total_Errors_Detected /= 0 then
               return;
            else
               raise Program_Error;
            end if;
         end if;

         -- A very specialized error check, if the undefined variable is
         -- a case tag, and the case type is an enumeration type, check
         -- for a possible misspelling, and if so, modify the identifier

         -- Named aggregate should also be handled similarly ???

         if Nkind (N) = N_Identifier
           and then Nkind (Parent (N)) = N_Case_Statement_Alternative
         then
            Get_Name_String (Chars (N));

            declare
               Case_Str : constant String := Name_Buffer (1 .. Name_Len);
               Case_Stm : constant Node_Id := Parent (Parent (N));
               Case_Typ : constant Entity_Id := Etype (Expression (Case_Stm));
               Case_Rtp : constant Entity_Id := Root_Type (Case_Typ);

               Lit : Node_Id;

            begin
               if Is_Enumeration_Type (Case_Typ)
                 and then Case_Rtp /= Standard_Character
                 and then Case_Rtp /= Standard_Wide_Character
                 and then Case_Rtp /= Standard_Wide_Wide_Character
               then
                  Lit := First_Literal (Case_Typ);
                  Get_Name_String (Chars (Lit));

                  if Chars (Lit) /= Chars (N)
                    and then Is_Bad_Spelling_Of
                      (Case_Str, Name_Buffer (1 .. Name_Len))
                  then
                     Error_Msg_Node_2 := Lit;
                     Error_Msg_N
                       ("& is undefined, assume misspelling of &", N);
                     Rewrite (N, New_Occurrence_Of (Lit, Sloc (N)));
                     return;
                  end if;

                  Lit := Next_Literal (Lit);
               end if;
            end;
         end if;

         -- Normal processing

         Set_Entity (N, Any_Id);
         Set_Etype (N, Any_Type);

         -- We use the table Urefs to keep track of entities for which we
         -- have issued errors for undefined references. Multiple errors
         -- for a single name are normally suppressed, however we modify
         -- the error message to alert the programmer to this effect.

         for J in Urefs.First .. Urefs.Last loop
            if Chars (N) = Chars (Urefs.Table (J).Node) then
               if Urefs.Table (J).Err /= No_Error_Msg
                 and then Sloc (N) /= Urefs.Table (J).Loc
               then
                  Error_Msg_Node_1 := Urefs.Table (J).Node;

                  if Urefs.Table (J).Nvis then
                     Change_Error_Text (Urefs.Table (J).Err,
                       "& is not visible (more references follow)");
                  else
                     Change_Error_Text (Urefs.Table (J).Err,
                       "& is undefined (more references follow)");
                  end if;

                  Urefs.Table (J).Err := No_Error_Msg;
               end if;

               -- Although we will set Msg False, and thus suppress the
               -- message, we also set Error_Posted True, to avoid any
               -- cascaded messages resulting from the undefined reference.

               Msg := False;
               Set_Error_Posted (N, True);
               return;
            end if;
         end loop;

         -- If entry not found, this is first undefined occurrence

         if Nvis then
            Error_Msg_N ("& is not visible!", N);
            Emsg := Get_Msg_Id;

         else
            Error_Msg_N ("& is undefined!", N);
            Emsg := Get_Msg_Id;

            -- A very bizarre special check, if the undefined identifier
            -- is put or put_line, then add a special error message (since
            -- this is a very common error for beginners to make).

            if Chars (N) = Name_Put or else Chars (N) = Name_Put_Line then
               Error_Msg_N ("\possible missing with of 'Text_'I'O!", N);
            end if;

            -- Now check for possible misspellings

            Get_Name_String (Chars (N));

            declare
               E : Entity_Id;
               Ematch : Entity_Id := Empty;

               Last_Name_Id : constant Name_Id :=
                                Name_Id (Nat (First_Name_Id) +
                                           Name_Entries_Count - 1);

               S : constant String (1 .. Name_Len) :=
                      Name_Buffer (1 .. Name_Len);

            begin
               for N in First_Name_Id .. Last_Name_Id loop
                  E := Get_Name_Entity_Id (N);

                  if Present (E)
                     and then (Is_Immediately_Visible (E)
                                 or else
                               Is_Potentially_Use_Visible (E))
                  then
                     Get_Name_String (N);

                     if Is_Bad_Spelling_Of
                          (Name_Buffer (1 .. Name_Len), S)
                     then
                        Ematch := E;
                        exit;
                     end if;
                  end if;
               end loop;

               if Present (Ematch) then
                  Error_Msg_NE ("\possible misspelling of&", N, Ematch);
               end if;
            end;
         end if;

         -- Make entry in undefined references table unless the full
         -- errors switch is set, in which case by refraining from
         -- generating the table entry, we guarantee that we get an
         -- error message for every undefined reference.

         if not All_Errors_Mode then
            Urefs.Increment_Last;
            Urefs.Table (Urefs.Last).Node := N;
            Urefs.Table (Urefs.Last).Err := Emsg;
            Urefs.Table (Urefs.Last).Nvis := Nvis;
            Urefs.Table (Urefs.Last).Loc := Sloc (N);
         end if;

         Msg := True;
      end Undefined;

   -- Start of processing for Find_Direct_Name

   begin
      -- If the entity pointer is already set, this is an internal node, or
      -- a node that is analyzed more than once, after a tree modification.
      -- In such a case there is no resolution to perform, just set the type.

      if Present (Entity (N)) then
         if Is_Type (Entity (N)) then
            Set_Etype (N, Entity (N));

         else
            declare
               Entyp : constant Entity_Id := Etype (Entity (N));

            begin
               -- One special case here. If the Etype field is already set,
               -- and references the packed array type corresponding to the
               -- etype of the referenced entity, then leave it alone. This
               -- happens for trees generated from Exp_Pakd, where expressions
               -- can be deliberately "mis-typed" to the packed array type.

               if Is_Array_Type (Entyp)
                 and then Is_Packed (Entyp)
                 and then Present (Etype (N))
                 and then Etype (N) = Packed_Array_Type (Entyp)
               then
                  null;

               -- If not that special case, then just reset the Etype

               else
                  Set_Etype (N, Etype (Entity (N)));
               end if;
            end;
         end if;

         return;
      end if;

      -- Here if Entity pointer was not set, we need full visibility analysis
      -- First we generate debugging output if the debug E flag is set.

      if Debug_Flag_E then
         Write_Str ("Looking for ");
         Write_Name (Chars (N));
         Write_Eol;
      end if;

      Homonyms := Current_Entity (N);
      Nvis_Entity := False;

      E := Homonyms;
      while Present (E) loop

         -- If entity is immediately visible or potentially use
         -- visible, then process the entity and we are done.

         if Is_Immediately_Visible (E) then
            goto Immediately_Visible_Entity;

         elsif Is_Potentially_Use_Visible (E) then
            goto Potentially_Use_Visible_Entity;

         -- Note if a known but invisible entity encountered

         elsif Known_But_Invisible (E) then
            Nvis_Entity := True;
         end if;

         -- Move to next entity in chain and continue search

         E := Homonym (E);
      end loop;

      -- If no entries on homonym chain that were potentially visible,
      -- and no entities reasonably considered as non-visible, then
      -- we have a plain undefined reference, with no additional
      -- explanation required!

      if not Nvis_Entity then
         Undefined (Nvis => False);

      -- Otherwise there is at least one entry on the homonym chain that
      -- is reasonably considered as being known and non-visible.

      else
         Nvis_Messages;
      end if;

      return;

      -- Processing for a potentially use visible entry found. We must search
      -- the rest of the homonym chain for two reasons. First, if there is a
      -- directly visible entry, then none of the potentially use-visible
      -- entities are directly visible (RM 8.4(10)). Second, we need to check
      -- for the case of multiple potentially use-visible entries hiding one
      -- another and as a result being non-directly visible (RM 8.4(11)).

      <<Potentially_Use_Visible_Entity>> declare
         Only_One_Visible : Boolean := True;
         All_Overloadable : Boolean := Is_Overloadable (E);

      begin
         E2 := Homonym (E);

         while Present (E2) loop
            if Is_Immediately_Visible (E2) then

               -- If the use-visible entity comes from the actual for a
               -- formal package, it hides a directly visible entity from
               -- outside the instance.

               if From_Actual_Package (E)
                 and then Scope_Depth (E2) < Scope_Depth (Inst)
               then
                  goto Found;
               else
                  E := E2;
                  goto Immediately_Visible_Entity;
               end if;

            elsif Is_Potentially_Use_Visible (E2) then
               Only_One_Visible := False;
               All_Overloadable := All_Overloadable and Is_Overloadable (E2);

            -- Ada 2005 (AI-262): Protect against a form of Beujolais effect
            -- that can occurr in private_with clauses. Example:

            -- with A;
            -- private with B; package A is
            -- package C is function B return Integer;
            -- use A; end A;
            -- V1 : Integer := B;
            -- private function B return Integer;
            -- V2 : Integer := B;
            -- end C;

            -- V1 resolves to A.B, but V2 resolves to library unit B

            elsif Ekind (E2) = E_Function
              and then Scope (E2) = Standard_Standard
              and then Has_Private_With (E2)
            then
               Only_One_Visible := False;
               All_Overloadable := False;
               Nvis_Is_Private_Subprg := True;
               exit;
            end if;

            E2 := Homonym (E2);
         end loop;

         -- On falling through this loop, we have checked that there are no
         -- immediately visible entities. Only_One_Visible is set if exactly
         -- one potentially use visible entity exists. All_Overloadable is
         -- set if all the potentially use visible entities are overloadable.
         -- The condition for legality is that either there is one potentially
         -- use visible entity, or if there is more than one, then all of them
         -- are overloadable.

         if Only_One_Visible or All_Overloadable then
            goto Found;

         -- If there is more than one potentially use-visible entity and at
         -- least one of them non-overloadable, we have an error (RM 8.4(11).
         -- Note that E points to the first such entity on the homonym list.
         -- Special case: if one of the entities is declared in an actual
         -- package, it was visible in the generic, and takes precedence over
         -- other entities that are potentially use-visible. Same if it is
         -- declared in a local instantiation of the current instance.

         else
            if In_Instance then
               Inst := Current_Scope;

               -- Find current instance

               while Present (Inst)
                 and then Inst /= Standard_Standard
               loop
                  if Is_Generic_Instance (Inst) then
                     exit;
                  end if;

                  Inst := Scope (Inst);
               end loop;

               E2 := E;

               while Present (E2) loop
                  if From_Actual_Package (E2)
                    or else
                      (Is_Generic_Instance (Scope (E2))
                        and then Scope_Depth (Scope (E2)) > Scope_Depth (Inst))
                  then
                     E := E2;
                     goto Found;
                  end if;

                  E2 := Homonym (E2);
               end loop;

               Nvis_Messages;
               return;

            elsif
              Is_Predefined_File_Name (Unit_File_Name (Current_Sem_Unit))
            then
               -- A use-clause in the body of a system file creates conflict
               -- with some entity in a user scope, while rtsfind is active.
               -- Keep only the entity coming from another predefined unit.

               E2 := E;
               while Present (E2) loop
                  if Is_Predefined_File_Name
                    (Unit_File_Name (Get_Source_Unit (Sloc (E2))))
                  then
                     E := E2;
                     goto Found;
                  end if;

                  E2 := Homonym (E2);
               end loop;

               -- Entity must exist because predefined unit is correct

               raise Program_Error;

            else
               Nvis_Messages;
               return;
            end if;
         end if;
      end;

      -- Come here with E set to the first immediately visible entity on
      -- the homonym chain. This is the one we want unless there is another
      -- immediately visible entity further on in the chain for a more
      -- inner scope (RM 8.3(8)).

      <<Immediately_Visible_Entity>> declare
         Level : Int;
         Scop : Entity_Id;

      begin
         -- Find scope level of initial entity. When compiling through
         -- Rtsfind, the previous context is not completely invisible, and
         -- an outer entity may appear on the chain, whose scope is below
         -- the entry for Standard that delimits the current scope stack.
         -- Indicate that the level for this spurious entry is outside of
         -- the current scope stack.

         Level := Scope_Stack.Last;
         loop
            Scop := Scope_Stack.Table (Level).Entity;
            exit when Scop = Scope (E);
            Level := Level - 1;
            exit when Scop = Standard_Standard;
         end loop;

         -- Now search remainder of homonym chain for more inner entry
         -- If the entity is Standard itself, it has no scope, and we
         -- compare it with the stack entry directly.

         E2 := Homonym (E);
         while Present (E2) loop
            if Is_Immediately_Visible (E2) then

               -- If a generic package contains a local declaration that
               -- has the same name as the generic, there may be a visibility
               -- conflict in an instance, where the local declaration must
               -- also hide the name of the corresponding package renaming.
               -- We check explicitly for a package declared by a renaming,
               -- whose renamed entity is an instance that is on the scope
               -- stack, and that contains a homonym in the same scope. Once
               -- we have found it, we know that the package renaming is not
               -- immediately visible, and that the identifier denotes the
               -- other entity (and its homonyms if overloaded).

               if Scope (E) = Scope (E2)
                 and then Ekind (E) = E_Package
                 and then Present (Renamed_Object (E))
                 and then Is_Generic_Instance (Renamed_Object (E))
                 and then In_Open_Scopes (Renamed_Object (E))
                 and then Comes_From_Source (N)
               then
                  Set_Is_Immediately_Visible (E, False);
                  E := E2;

               else
                  for J in Level + 1 .. Scope_Stack.Last loop
                     if Scope_Stack.Table (J).Entity = Scope (E2)
                       or else Scope_Stack.Table (J).Entity = E2
                     then
                        Level := J;
                        E := E2;
                        exit;
                     end if;
                  end loop;
               end if;
            end if;

            E2 := Homonym (E2);
         end loop;

         -- At the end of that loop, E is the innermost immediately
         -- visible entity, so we are all set.
      end;

      -- Come here with entity found, and stored in E

      <<Found>> begin

         if Comes_From_Source (N)
           and then Is_Remote_Access_To_Subprogram_Type (E)
           and then Expander_Active
           and then Get_PCS_Name /= Name_No_DSA
         then
            Rewrite (N,
              New_Occurrence_Of (Equivalent_Type (E), Sloc (N)));
            return;
         end if;

         Set_Entity (N, E);
         -- Why no Style_Check here???

         if Is_Type (E) then
            Set_Etype (N, E);
         else
            Set_Etype (N, Get_Full_View (Etype (E)));
         end if;

         if Debug_Flag_E then
            Write_Str (" found ");
            Write_Entity_Info (E, " ");
         end if;

         -- If the Ekind of the entity is Void, it means that all homonyms
         -- are hidden from all visibility (RM 8.3(5,14-20)). However, this
         -- test is skipped if the current scope is a record and the name is
         -- a pragma argument expression (case of Atomic and Volatile pragmas
         -- and possibly other similar pragmas added later, which are allowed
         -- to reference components in the current record).

         if Ekind (E) = E_Void
           and then
             (not Is_Record_Type (Current_Scope)
               or else Nkind (Parent (N)) /= N_Pragma_Argument_Association)
         then
            Premature_Usage (N);

         -- If the entity is overloadable, collect all interpretations
         -- of the name for subsequent overload resolution. We optimize
         -- a bit here to do this only if we have an overloadable entity
         -- that is not on its own on the homonym chain.

         elsif Is_Overloadable (E)
           and then (Present (Homonym (E)) or else Current_Entity (N) /= E)
         then
            Collect_Interps (N);

            -- If no homonyms were visible, the entity is unambiguous

            if not Is_Overloaded (N) then
               Generate_Reference (E, N);
            end if;

         -- Case of non-overloadable entity, set the entity providing that
         -- we do not have the case of a discriminant reference within a
         -- default expression. Such references are replaced with the
         -- corresponding discriminal, which is the formal corresponding to
         -- to the discriminant in the initialization procedure.

         else
            -- Entity is unambiguous, indicate that it is referenced here
            -- One slightly odd case is that we do not want to set the
            -- Referenced flag if the entity is a label, and the identifier
            -- is the label in the source, since this is not a reference
            -- from the point of view of the user

            if Nkind (Parent (N)) = N_Label then
               declare
                  R : constant Boolean := Referenced (E);

               begin
                  Generate_Reference (E, N);
                  Set_Referenced (E, R);
               end;

            -- Normal case, not a label. Generate reference

            else
               Generate_Reference (E, N);
            end if;

            -- Set Entity, with style check if need be. If this is a
            -- discriminant reference, it must be replaced by the
            -- corresponding discriminal, that is to say the parameter
            -- of the initialization procedure that corresponds to the
            -- discriminant. If this replacement is being performed, there
            -- is no style check to perform.

            -- This replacement must not be done if we are currently
            -- processing a generic spec or body, because the discriminal
            -- has not been not generated in this case.

            if not In_Default_Expression
              or else Ekind (E) /= E_Discriminant
              or else Inside_A_Generic
            then
               Set_Entity_With_Style_Check (N, E);

            -- The replacement is not done either for a task discriminant that
            -- appears in a default expression of an entry parameter. See
            -- Expand_Discriminant in exp_ch2 for details on their handling.

            elsif Is_Concurrent_Type (Scope (E)) then
               declare
                  P : Node_Id := Parent (N);

               begin
                  while Present (P)
                    and then Nkind (P) /= N_Parameter_Specification
                    and then Nkind (P) /= N_Component_Declaration
                  loop
                     P := Parent (P);
                  end loop;

                  if Present (P)
                     and then Nkind (P) = N_Parameter_Specification
                  then
                     null;
                  else
                     Set_Entity (N, Discriminal (E));
                  end if;
               end;

            -- Otherwise, this is a discriminant in a context in which
            -- it is a reference to the corresponding parameter of the
            -- init proc for the enclosing type.

            else
               Set_Entity (N, Discriminal (E));
            end if;
         end if;
      end;
   end Find_Direct_Name;

   ------------------------
   -- Find_Expanded_Name --
   ------------------------

   -- This routine searches the homonym chain of the entity until it finds
   -- an entity declared in the scope denoted by the prefix. If the entity
   -- is private, it may nevertheless be immediately visible, if we are in
   -- the scope of its declaration.

   procedure Find_Expanded_Name (N : Node_Id) is
      Selector : constant Node_Id := Selector_Name (N);
      Candidate : Entity_Id := Empty;
      P_Name : Entity_Id;
      O_Name : Entity_Id;
      Id : Entity_Id;

   begin
      P_Name := Entity (Prefix (N));
      O_Name := P_Name;

      -- If the prefix is a renamed package, look for the entity
      -- in the original package.

      if Ekind (P_Name) = E_Package
        and then Present (Renamed_Object (P_Name))
      then
         P_Name := Renamed_Object (P_Name);

         -- Rewrite node with entity field pointing to renamed object

         Rewrite (Prefix (N), New_Copy (Prefix (N)));
         Set_Entity (Prefix (N), P_Name);

      -- If the prefix is an object of a concurrent type, look for
      -- the entity in the associated task or protected type.

      elsif Is_Concurrent_Type (Etype (P_Name)) then
         P_Name := Etype (P_Name);
      end if;

      Id := Current_Entity (Selector);

      while Present (Id) loop

         if Scope (Id) = P_Name then
            Candidate := Id;

            if Is_Child_Unit (Id) then
               exit when Is_Visible_Child_Unit (Id)
                 or else Is_Immediately_Visible (Id);

            else
               exit when not Is_Hidden (Id)
                 or else Is_Immediately_Visible (Id);
            end if;
         end if;

         Id := Homonym (Id);
      end loop;

      if No (Id)
        and then (Ekind (P_Name) = E_Procedure
                    or else
                  Ekind (P_Name) = E_Function)
        and then Is_Generic_Instance (P_Name)
      then
         -- Expanded name denotes entity in (instance of) generic subprogram.
         -- The entity may be in the subprogram instance, or may denote one of
         -- the formals, which is declared in the enclosing wrapper package.

         P_Name := Scope (P_Name);

         Id := Current_Entity (Selector);
         while Present (Id) loop
            exit when Scope (Id) = P_Name;
            Id := Homonym (Id);
         end loop;
      end if;

      if No (Id) or else Chars (Id) /= Chars (Selector) then
         Set_Etype (N, Any_Type);

         -- If we are looking for an entity defined in System, try to
         -- find it in the child package that may have been provided as
         -- an extension to System. The Extend_System pragma will have
         -- supplied the name of the extension, which may have to be loaded.

         if Chars (P_Name) = Name_System
           and then Scope (P_Name) = Standard_Standard
           and then Present (System_Extend_Unit)
           and then Present_System_Aux (N)
         then
            Set_Entity (Prefix (N), System_Aux_Id);
            Find_Expanded_Name (N);
            return;

         elsif Nkind (Selector) = N_Operator_Symbol
           and then Has_Implicit_Operator (N)
         then
            -- There is an implicit instance of the predefined operator in
            -- the given scope. The operator entity is defined in Standard.
            -- Has_Implicit_Operator makes the node into an Expanded_Name.

            return;

         elsif Nkind (Selector) = N_Character_Literal
           and then Has_Implicit_Character_Literal (N)
         then
            -- If there is no literal defined in the scope denoted by the
            -- prefix, the literal may belong to (a type derived from)
            -- Standard_Character, for which we have no explicit literals.

            return;

         else
            -- If the prefix is a single concurrent object, use its
            -- name in the error message, rather than that of the
            -- anonymous type.

            if Is_Concurrent_Type (P_Name)
              and then Is_Internal_Name (Chars (P_Name))
            then
               Error_Msg_Node_2 := Entity (Prefix (N));
            else
               Error_Msg_Node_2 := P_Name;
            end if;

            if P_Name = System_Aux_Id then
               P_Name := Scope (P_Name);
               Set_Entity (Prefix (N), P_Name);
            end if;

            if Present (Candidate) then

               if Is_Child_Unit (Candidate) then

                  -- If the candidate is a private child unit and we are
                  -- in the visible part of a public unit, specialize the
                  -- error message. There might be a private with_clause for
                  -- it, but it is not currently active.

                  if Is_Private_Descendant (Candidate)
                    and then Ekind (Current_Scope) = E_Package
                    and then not In_Private_Part (Current_Scope)
                    and then not Is_Private_Descendant (Current_Scope)
                  then
                     Error_Msg_N ("private child unit& is not visible here",
                       Selector);
                  else
                     Error_Msg_N
                       ("missing with_clause for child unit &", Selector);
                  end if;
               else
                  Error_Msg_NE ("& is not a visible entity of&", N, Selector);
               end if;

            else
               -- Within the instantiation of a child unit, the prefix may
               -- denote the parent instance, but the selector has the
               -- name of the original child. Find whether we are within
               -- the corresponding instance, and get the proper entity, which
               -- can only be an enclosing scope.

               if O_Name /= P_Name
                 and then In_Open_Scopes (P_Name)
                 and then Is_Generic_Instance (P_Name)
               then
                  declare
                     S : Entity_Id := Current_Scope;
                     P : Entity_Id;

                  begin
                     for J in reverse 0 .. Scope_Stack.Last loop
                        S := Scope_Stack.Table (J).Entity;

                        exit when S = Standard_Standard;

                        if Ekind (S) = E_Function
                          or else Ekind (S) = E_Package
                          or else Ekind (S) = E_Procedure
                        then
                           P := Generic_Parent (Specification
                                  (Unit_Declaration_Node (S)));

                           if Present (P)
                             and then Chars (Scope (P)) = Chars (O_Name)
                             and then Chars (P) = Chars (Selector)
                           then
                              Id := S;
                              goto Found;
                           end if;
                        end if;

                     end loop;
                  end;
               end if;

               if Chars (P_Name) = Name_Ada
                 and then Scope (P_Name) = Standard_Standard
               then
                  Error_Msg_Node_2 := Selector;
                  Error_Msg_NE ("missing with for `&.&`", N, P_Name);

               -- If this is a selection from a dummy package, then
               -- suppress the error message, of course the entity
               -- is missing if the package is missing!

               elsif Sloc (Error_Msg_Node_2) = No_Location then
                  null;

               -- Here we have the case of an undefined component

               else

                  Error_Msg_NE ("& not declared in&", N, Selector);

                  -- Check for misspelling of some entity in prefix

                  Id := First_Entity (P_Name);
                  Get_Name_String (Chars (Selector));

                  declare
                     S : constant String (1 .. Name_Len) :=
                            Name_Buffer (1 .. Name_Len);
                  begin
                     while Present (Id) loop
                        Get_Name_String (Chars (Id));
                        if Is_Bad_Spelling_Of
                          (Name_Buffer (1 .. Name_Len), S)
                          and then not Is_Internal_Name (Chars (Id))
                        then
                           Error_Msg_NE
                             ("possible misspelling of&", Selector, Id);
                           exit;
                        end if;

                        Next_Entity (Id);
                     end loop;
                  end;

                  -- Specialize the message if this may be an instantiation
                  -- of a child unit that was not mentioned in the context.

                  if Nkind (Parent (N)) = N_Package_Instantiation
                    and then Is_Generic_Instance (Entity (Prefix (N)))
                    and then Is_Compilation_Unit
                     (Generic_Parent (Parent (Entity (Prefix (N)))))
                  then
                     Error_Msg_NE
                      ("\possible missing with clause on child unit&",
                        N, Selector);
                  end if;
               end if;
            end if;

            Id := Any_Id;
         end if;
      end if;

      <<Found>>
      if Comes_From_Source (N)
        and then Is_Remote_Access_To_Subprogram_Type (Id)
        and then Present (Equivalent_Type (Id))
      then
         -- If we are not actually generating distribution code (i.e.
         -- the current PCS is the dummy non-distributed version), then
         -- the Equivalent_Type will be missing, and Id should be treated
         -- as a regular access-to-subprogram type.

         Id := Equivalent_Type (Id);
         Set_Chars (Selector, Chars (Id));
      end if;

      -- Ada 2005 (AI-50217): Check usage of entities in limited withed units

      if Ekind (P_Name) = E_Package
        and then From_With_Type (P_Name)
      then
         if From_With_Type (Id)
           or else Is_Type (Id)
           or else Ekind (Id) = E_Package
         then
            null;
         else
            Error_Msg_N
              ("limited withed package can only be used to access "
               & " incomplete types",
                N);
         end if;
      end if;

      if Is_Task_Type (P_Name)
        and then ((Ekind (Id) = E_Entry
                    and then Nkind (Parent (N)) /= N_Attribute_Reference)
                    or else
                  (Ekind (Id) = E_Entry_Family
                    and then
                      Nkind (Parent (Parent (N))) /= N_Attribute_Reference))
      then
         -- It is an entry call after all, either to the current task
         -- (which will deadlock) or to an enclosing task.

         Analyze_Selected_Component (N);
         return;
      end if;

      Change_Selected_Component_To_Expanded_Name (N);

      -- Do style check and generate reference, but skip both steps if this
      -- entity has homonyms, since we may not have the right homonym set
      -- yet. The proper homonym will be set during the resolve phase.

      if Has_Homonym (Id) then
         Set_Entity (N, Id);
      else
         Set_Entity_With_Style_Check (N, Id);
         Generate_Reference (Id, N);
      end if;

      if Is_Type (Id) then
         Set_Etype (N, Id);
      else
         Set_Etype (N, Get_Full_View (Etype (Id)));
      end if;

      -- If the Ekind of the entity is Void, it means that all homonyms
      -- are hidden from all visibility (RM 8.3(5,14-20)).

      if Ekind (Id) = E_Void then
         Premature_Usage (N);

      elsif Is_Overloadable (Id)
        and then Present (Homonym (Id))
      then
         declare
            H : Entity_Id := Homonym (Id);

         begin
            while Present (H) loop
               if Scope (H) = Scope (Id)
                 and then
                   (not Is_Hidden (H)
                      or else Is_Immediately_Visible (H))
               then
                  Collect_Interps (N);
                  exit;
               end if;

               H := Homonym (H);
            end loop;

            -- If an extension of System is present, collect possible
            -- explicit overloadings declared in the extension.

            if Chars (P_Name) = Name_System
              and then Scope (P_Name) = Standard_Standard
              and then Present (System_Extend_Unit)
              and then Present_System_Aux (N)
            then
               H := Current_Entity (Id);

               while Present (H) loop
                  if Scope (H) = System_Aux_Id then
                     Add_One_Interp (N, H, Etype (H));
                  end if;

                  H := Homonym (H);
               end loop;
            end if;
         end;
      end if;

      if Nkind (Selector_Name (N)) = N_Operator_Symbol
        and then Scope (Id) /= Standard_Standard
      then
         -- In addition to user-defined operators in the given scope,
         -- there may be an implicit instance of the predefined
         -- operator. The operator (defined in Standard) is found
         -- in Has_Implicit_Operator, and added to the interpretations.
         -- Procedure Add_One_Interp will determine which hides which.

         if Has_Implicit_Operator (N) then
            null;
         end if;
      end if;
   end Find_Expanded_Name;

   -------------------------
   -- Find_Renamed_Entity --
   -------------------------

   function Find_Renamed_Entity
     (N : Node_Id;
      Nam : Node_Id;
      New_S : Entity_Id;
      Is_Actual : Boolean := False) return Entity_Id
   is
      Ind : Interp_Index;
      I1 : Interp_Index := 0; -- Suppress junk warnings
      It : Interp;
      It1 : Interp;
      Old_S : Entity_Id;
      Inst : Entity_Id;

      function Enclosing_Instance return Entity_Id;
      -- If the renaming determines the entity for the default of a formal
      -- subprogram nested within another instance, choose the innermost
      -- candidate. This is because if the formal has a box, and we are within
      -- an enclosing instance where some candidate interpretations are local
      -- to this enclosing instance, we know that the default was properly
      -- resolved when analyzing the generic, so we prefer the local
      -- candidates to those that are external. This is not always the case
      -- but is a reasonable heuristic on the use of nested generics.
      -- The proper solution requires a full renaming model.

      function Within (Inner, Outer : Entity_Id) return Boolean;
      -- Determine whether a candidate subprogram is defined within
      -- the enclosing instance. If yes, it has precedence over outer
      -- candidates.

      function Is_Visible_Operation (Op : Entity_Id) return Boolean;
      -- If the renamed entity is an implicit operator, check whether it is
      -- visible because its operand type is properly visible. This
      -- check applies to explicit renamed entities that appear in the
      -- source in a renaming declaration or a formal subprogram instance,
      -- but not to default generic actuals with a name.

      ------------------------
      -- Enclosing_Instance --
      ------------------------

      function Enclosing_Instance return Entity_Id is
         S : Entity_Id;

      begin
         if not Is_Generic_Instance (Current_Scope)
           and then not Is_Actual
         then
            return Empty;
         end if;

         S := Scope (Current_Scope);

         while S /= Standard_Standard loop

            if Is_Generic_Instance (S) then
               return S;
            end if;

            S := Scope (S);
         end loop;

         return Empty;
      end Enclosing_Instance;

      --------------------------
      -- Is_Visible_Operation --
      --------------------------

      function Is_Visible_Operation (Op : Entity_Id) return Boolean is
         Scop : Entity_Id;
         Typ : Entity_Id;
         Btyp : Entity_Id;

      begin
         if Ekind (Op) /= E_Operator
           or else Scope (Op) /= Standard_Standard
           or else (In_Instance
                      and then
                        (not Is_Actual
                           or else Present (Enclosing_Instance)))
         then
            return True;

         else
            -- For a fixed point type operator, check the resulting type,
            -- because it may be a mixed mode integer * fixed operation.

            if Present (Next_Formal (First_Formal (New_S)))
              and then Is_Fixed_Point_Type (Etype (New_S))
            then
               Typ := Etype (New_S);
            else
               Typ := Etype (First_Formal (New_S));
            end if;

            Btyp := Base_Type (Typ);

            if Nkind (Nam) /= N_Expanded_Name then
               return (In_Open_Scopes (Scope (Btyp))
                        or else Is_Potentially_Use_Visible (Btyp)
                        or else In_Use (Btyp)
                        or else In_Use (Scope (Btyp)));

            else
               Scop := Entity (Prefix (Nam));

               if Ekind (Scop) = E_Package
                 and then Present (Renamed_Object (Scop))
               then
                  Scop := Renamed_Object (Scop);
               end if;

               -- Operator is visible if prefix of expanded name denotes
               -- scope of type, or else type type is defined in System_Aux
               -- and the prefix denotes System.

               return Scope (Btyp) = Scop
                 or else (Scope (Btyp) = System_Aux_Id
                           and then Scope (Scope (Btyp)) = Scop);
            end if;
         end if;
      end Is_Visible_Operation;

      ------------
      -- Within --
      ------------

      function Within (Inner, Outer : Entity_Id) return Boolean is
         Sc : Entity_Id := Scope (Inner);

      begin
         while Sc /= Standard_Standard loop

            if Sc = Outer then
               return True;
            else
               Sc := Scope (Sc);
            end if;
         end loop;

         return False;
      end Within;

      function Report_Overload return Entity_Id;
      -- List possible interpretations, and specialize message in the
      -- case of a generic actual.

      function Report_Overload return Entity_Id is
      begin
         if Is_Actual then
            Error_Msg_NE
              ("ambiguous actual subprogram&, " &
                 "possible interpretations: ", N, Nam);
         else
            Error_Msg_N
              ("ambiguous subprogram, " &
                 "possible interpretations: ", N);
         end if;

         List_Interps (Nam, N);
         return Old_S;
      end Report_Overload;

   -- Start of processing for Find_Renamed_Entry

   begin
      Old_S := Any_Id;
      Candidate_Renaming := Empty;

      if not Is_Overloaded (Nam) then
         if Entity_Matches_Spec (Entity (Nam), New_S)
           and then Is_Visible_Operation (Entity (Nam))
         then
            Old_S := Entity (Nam);

         elsif
           Present (First_Formal (Entity (Nam)))
             and then Present (First_Formal (New_S))
             and then (Base_Type (Etype (First_Formal (Entity (Nam))))
                        = Base_Type (Etype (First_Formal (New_S))))
         then
            Candidate_Renaming := Entity (Nam);
         end if;

      else
         Get_First_Interp (Nam, Ind, It);

         while Present (It.Nam) loop

            if Entity_Matches_Spec (It.Nam, New_S)
               and then Is_Visible_Operation (It.Nam)
            then
               if Old_S /= Any_Id then

                  -- Note: The call to Disambiguate only happens if a
                  -- previous interpretation was found, in which case I1
                  -- has received a value.

                  It1 := Disambiguate (Nam, I1, Ind, Etype (Old_S));

                  if It1 = No_Interp then

                     Inst := Enclosing_Instance;

                     if Present (Inst) then

                        if Within (It.Nam, Inst) then
                           return (It.Nam);

                        elsif Within (Old_S, Inst) then
                           return (Old_S);

                        else
                           return Report_Overload;
                        end if;

                     else
                        return Report_Overload;
                     end if;

                  else
                     Old_S := It1.Nam;
                     exit;
                  end if;

               else
                  I1 := Ind;
                  Old_S := It.Nam;
               end if;

            elsif
              Present (First_Formal (It.Nam))
                and then Present (First_Formal (New_S))
                and then (Base_Type (Etype (First_Formal (It.Nam)))
                            = Base_Type (Etype (First_Formal (New_S))))
            then
               Candidate_Renaming := It.Nam;
            end if;

            Get_Next_Interp (Ind, It);
         end loop;

         Set_Entity (Nam, Old_S);
         Set_Is_Overloaded (Nam, False);
      end if;

      return Old_S;
   end Find_Renamed_Entity;

   -----------------------------
   -- Find_Selected_Component --
   -----------------------------

   procedure Find_Selected_Component (N : Node_Id) is
      P : constant Node_Id := Prefix (N);

      P_Name : Entity_Id;
      -- Entity denoted by prefix

      P_Type : Entity_Id;
      -- and its type

      Nam : Node_Id;

   begin
      Analyze (P);

      if Nkind (P) = N_Error then
         return;

      -- If the selector already has an entity, the node has been
      -- constructed in the course of expansion, and is known to be
      -- valid. Do not verify that it is defined for the type (it may
      -- be a private component used in the expansion of record equality).

      elsif Present (Entity (Selector_Name (N))) then

         if No (Etype (N))
           or else Etype (N) = Any_Type
         then
            declare
               Sel_Name : constant Node_Id := Selector_Name (N);
               Selector : constant Entity_Id := Entity (Sel_Name);
               C_Etype : Node_Id;

            begin
               Set_Etype (Sel_Name, Etype (Selector));

               if not Is_Entity_Name (P) then
                  Resolve (P);
               end if;

               -- Build an actual subtype except for the first parameter
               -- of an init proc, where this actual subtype is by
               -- definition incorrect, since the object is uninitialized
               -- (and does not even have defined discriminants etc.)

               if Is_Entity_Name (P)
                 and then Ekind (Entity (P)) = E_Function
               then
                  Nam := New_Copy (P);

                  if Is_Overloaded (P) then
                     Save_Interps (P, Nam);
                  end if;

                  Rewrite (P,
                    Make_Function_Call (Sloc (P), Name => Nam));
                  Analyze_Call (P);
                  Analyze_Selected_Component (N);
                  return;

               elsif Ekind (Selector) = E_Component
                 and then (not Is_Entity_Name (P)
                            or else Chars (Entity (P)) /= Name_uInit)
               then
                  C_Etype :=
                    Build_Actual_Subtype_Of_Component (
                      Etype (Selector), N);
               else
                  C_Etype := Empty;
               end if;

               if No (C_Etype) then
                  C_Etype := Etype (Selector);
               else
                  Insert_Action (N, C_Etype);
                  C_Etype := Defining_Identifier (C_Etype);
               end if;

               Set_Etype (N, C_Etype);
            end;

            -- If this is the name of an entry or protected operation, and
            -- the prefix is an access type, insert an explicit dereference,
            -- so that entry calls are treated uniformly.

            if Is_Access_Type (Etype (P))
              and then Is_Concurrent_Type (Designated_Type (Etype (P)))
            then
               declare
                  New_P : constant Node_Id :=
                            Make_Explicit_Dereference (Sloc (P),
                              Prefix => Relocate_Node (P));
               begin
                  Rewrite (P, New_P);
                  Set_Etype (P, Designated_Type (Etype (Prefix (P))));
               end;
            end if;

         -- If the selected component appears within a default expression
         -- and it has an actual subtype, the pre-analysis has not yet
         -- completed its analysis, because Insert_Actions is disabled in
         -- that context. Within the init proc of the enclosing type we
         -- must complete this analysis, if an actual subtype was created.

         elsif Inside_Init_Proc then
            declare
               Typ : constant Entity_Id := Etype (N);
               Decl : constant Node_Id := Declaration_Node (Typ);

            begin
               if Nkind (Decl) = N_Subtype_Declaration
                 and then not Analyzed (Decl)
                 and then Is_List_Member (Decl)
                 and then No (Parent (Decl))
               then
                  Remove (Decl);
                  Insert_Action (N, Decl);
               end if;
            end;
         end if;

         return;

      elsif Is_Entity_Name (P) then
         P_Name := Entity (P);

         -- The prefix may denote an enclosing type which is the completion
         -- of an incomplete type declaration.

         if Is_Type (P_Name) then
            Set_Entity (P, Get_Full_View (P_Name));
            Set_Etype (P, Entity (P));
            P_Name := Entity (P);
         end if;

         P_Type := Base_Type (Etype (P));

         if Debug_Flag_E then
            Write_Str ("Found prefix type to be ");
            Write_Entity_Info (P_Type, " "); Write_Eol;
         end if;

         -- First check for components of a record object (not the
         -- result of a call, which is handled below).

         if Is_Appropriate_For_Record (P_Type)
           and then not Is_Overloadable (P_Name)
           and then not Is_Type (P_Name)
         then
            -- Selected component of record. Type checking will validate
            -- name of selector.

            Analyze_Selected_Component (N);

         elsif Is_Appropriate_For_Entry_Prefix (P_Type)
           and then not In_Open_Scopes (P_Name)
           and then (not Is_Concurrent_Type (Etype (P_Name))
                       or else not In_Open_Scopes (Etype (P_Name)))
         then
            -- Call to protected operation or entry. Type checking is
            -- needed on the prefix.

            Analyze_Selected_Component (N);

         elsif (In_Open_Scopes (P_Name)
                  and then Ekind (P_Name) /= E_Void
                  and then not Is_Overloadable (P_Name))
           or else (Is_Concurrent_Type (Etype (P_Name))
                      and then In_Open_Scopes (Etype (P_Name)))
         then
            -- Prefix denotes an enclosing loop, block, or task, i.e. an
            -- enclosing construct that is not a subprogram or accept.

            Find_Expanded_Name (N);

         elsif Ekind (P_Name) = E_Package then
            Find_Expanded_Name (N);

         elsif Is_Overloadable (P_Name) then

            -- The subprogram may be a renaming (of an enclosing scope) as
            -- in the case of the name of the generic within an instantiation.

            if (Ekind (P_Name) = E_Procedure
                 or else Ekind (P_Name) = E_Function)
              and then Present (Alias (P_Name))
              and then Is_Generic_Instance (Alias (P_Name))
            then
               P_Name := Alias (P_Name);
            end if;

            if Is_Overloaded (P) then

               -- The prefix must resolve to a unique enclosing construct

               declare
                  Found : Boolean := False;
                  Ind : Interp_Index;
                  It : Interp;

               begin
                  Get_First_Interp (P, Ind, It);

                  while Present (It.Nam) loop

                     if In_Open_Scopes (It.Nam) then
                        if Found then
                           Error_Msg_N (
                              "prefix must be unique enclosing scope", N);
                           Set_Entity (N, Any_Id);
                           Set_Etype (N, Any_Type);
                           return;

                        else
                           Found := True;
                           P_Name := It.Nam;
                        end if;
                     end if;

                     Get_Next_Interp (Ind, It);
                  end loop;
               end;
            end if;

            if In_Open_Scopes (P_Name) then
               Set_Entity (P, P_Name);
               Set_Is_Overloaded (P, False);
               Find_Expanded_Name (N);

            else
               -- If no interpretation as an expanded name is possible, it
               -- must be a selected component of a record returned by a
               -- function call. Reformat prefix as a function call, the
               -- rest is done by type resolution. If the prefix is a
               -- procedure or entry, as is P.X; this is an error.

               if Ekind (P_Name) /= E_Function
                 and then (not Is_Overloaded (P)
                             or else
                           Nkind (Parent (N)) = N_Procedure_Call_Statement)
               then

                  -- Prefix may mention a package that is hidden by a local
                  -- declaration: let the user know. Scan the full homonym
                  -- chain, the candidate package may be anywhere on it.

                  if Present (Homonym (Current_Entity (P_Name))) then

                     P_Name := Current_Entity (P_Name);

                     while Present (P_Name) loop
                        exit when Ekind (P_Name) = E_Package;
                        P_Name := Homonym (P_Name);
                     end loop;

                     if Present (P_Name) then
                        Error_Msg_Sloc := Sloc (Entity (Prefix (N)));

                        Error_Msg_NE
                          ("package& is hidden by declaration#",
                            N, P_Name);

                        Set_Entity (Prefix (N), P_Name);
                        Find_Expanded_Name (N);
                        return;
                     else
                        P_Name := Entity (Prefix (N));
                     end if;
                  end if;

                  Error_Msg_NE
                    ("invalid prefix in selected component&", N, P_Name);
                  Change_Selected_Component_To_Expanded_Name (N);
                  Set_Entity (N, Any_Id);
                  Set_Etype (N, Any_Type);

               else
                  Nam := New_Copy (P);
                  Save_Interps (P, Nam);
                  Rewrite (P,
                    Make_Function_Call (Sloc (P), Name => Nam));
                  Analyze_Call (P);
                  Analyze_Selected_Component (N);
               end if;
            end if;

         -- Remaining cases generate various error messages

         else
            -- Format node as expanded name, to avoid cascaded errors

            Change_Selected_Component_To_Expanded_Name (N);
            Set_Entity (N, Any_Id);
            Set_Etype (N, Any_Type);

            -- Issue error message, but avoid this if error issued already.
            -- Use identifier of prefix if one is available.

            if P_Name = Any_Id then
               null;

            elsif Ekind (P_Name) = E_Void then
               Premature_Usage (P);

            elsif Nkind (P) /= N_Attribute_Reference then
               Error_Msg_N (
                "invalid prefix in selected component&", P);

               if Is_Access_Type (P_Type)
                 and then Ekind (Designated_Type (P_Type)) = E_Incomplete_Type
               then
                  Error_Msg_N
                    ("\dereference must not be of an incomplete type " &
                       "('R'M 3.10.1)", P);
               end if;

            else
               Error_Msg_N (
                "invalid prefix in selected component", P);
            end if;
         end if;

      else
         -- If prefix is not the name of an entity, it must be an expression,
         -- whose type is appropriate for a record. This is determined by
         -- type resolution.

         Analyze_Selected_Component (N);
      end if;
   end Find_Selected_Component;

   ---------------
   -- Find_Type --
   ---------------

   procedure Find_Type (N : Node_Id) is
      C : Entity_Id;
      Typ : Entity_Id;
      T : Entity_Id;
      T_Name : Entity_Id;

   begin
      if N = Error then
         return;

      elsif Nkind (N) = N_Attribute_Reference then

         -- Class attribute. This is only valid in Ada 95 mode, but we don't
         -- do a check, since the tagged type referenced could only exist if
         -- we were in 95 mode when it was declared (or, if we were in Ada
         -- 83 mode, then an error message would already have been issued).

         if Attribute_Name (N) = Name_Class then
            Check_Restriction (No_Dispatch, N);
            Find_Type (Prefix (N));

            -- Propagate error from bad prefix

            if Etype (Prefix (N)) = Any_Type then
               Set_Entity (N, Any_Type);
               Set_Etype (N, Any_Type);
               return;
            end if;

            T := Base_Type (Entity (Prefix (N)));

            -- Case type is not known to be tagged. Its appearance in
            -- the prefix of the 'Class attribute indicates that the full
            -- view will be tagged.

            if not Is_Tagged_Type (T) then
               if Ekind (T) = E_Incomplete_Type then

                  -- It is legal to denote the class type of an incomplete
                  -- type. The full type will have to be tagged, of course.

                  Set_Is_Tagged_Type (T);
                  Set_Primitive_Operations (T, New_Elmt_List);
                  Make_Class_Wide_Type (T);
                  Set_Entity (N, Class_Wide_Type (T));
                  Set_Etype (N, Class_Wide_Type (T));

               elsif Ekind (T) = E_Private_Type
                 and then not Is_Generic_Type (T)
                 and then In_Private_Part (Scope (T))
               then
                  -- The Class attribute can be applied to an untagged
                  -- private type fulfilled by a tagged type prior to
                  -- the full type declaration (but only within the
                  -- parent package's private part). Create the class-wide
                  -- type now and check that the full type is tagged
                  -- later during its analysis. Note that we do not
                  -- mark the private type as tagged, unlike the case
                  -- of incomplete types, because the type must still
                  -- appear untagged to outside units.

                  if not Present (Class_Wide_Type (T)) then
                     Make_Class_Wide_Type (T);
                  end if;

                  Set_Entity (N, Class_Wide_Type (T));
                  Set_Etype (N, Class_Wide_Type (T));

               else
                  -- Should we introduce a type Any_Tagged and use
                  -- Wrong_Type here, it would be a bit more consistent???

                  Error_Msg_NE
                    ("tagged type required, found}",
                     Prefix (N), First_Subtype (T));
                  Set_Entity (N, Any_Type);
                  return;
               end if;

            -- Case of tagged type

            else
               if Is_Concurrent_Type (T) then
                  C := Class_Wide_Type
                         (Corresponding_Record_Type (Entity (Prefix (N))));
               else
                  C := Class_Wide_Type (Entity (Prefix (N)));
               end if;

               Set_Entity_With_Style_Check (N, C);
               Generate_Reference (C, N);
               Set_Etype (N, C);
            end if;

         -- Base attribute, not allowed in Ada 83

         elsif Attribute_Name (N) = Name_Base then
            if Ada_Version = Ada_83 and then Comes_From_Source (N) then
               Error_Msg_N
                 ("(Ada 83) Base attribute not allowed in subtype mark", N);

            else
               Find_Type (Prefix (N));
               Typ := Entity (Prefix (N));

               if Ada_Version >= Ada_95
                 and then not Is_Scalar_Type (Typ)
                 and then not Is_Generic_Type (Typ)
               then
                  Error_Msg_N
                    ("prefix of Base attribute must be scalar type",
                      Prefix (N));

               elsif Sloc (Typ) = Standard_Location
                 and then Base_Type (Typ) = Typ
                 and then Warn_On_Redundant_Constructs
               then
                  Error_Msg_NE
                    ("?redudant attribute, & is its own base type", N, Typ);
               end if;

               T := Base_Type (Typ);

               -- Rewrite attribute reference with type itself (see similar
               -- processing in Analyze_Attribute, case Base). Preserve
               -- prefix if present, for other legality checks.

               if Nkind (Prefix (N)) = N_Expanded_Name then
                  Rewrite (N,
                     Make_Expanded_Name (Sloc (N),
                       Chars => Chars (Entity (N)),
                       Prefix => New_Copy (Prefix (Prefix (N))),
                       Selector_Name =>
                         New_Reference_To (Entity (N), Sloc (N))));

               else
                  Rewrite (N,
                    New_Reference_To (Entity (N), Sloc (N)));
               end if;

               Set_Entity (N, T);
               Set_Etype (N, T);
            end if;

         -- All other attributes are invalid in a subtype mark

         else
            Error_Msg_N ("invalid attribute in subtype mark", N);
         end if;

      else
         Analyze (N);

         if Is_Entity_Name (N) then
            T_Name := Entity (N);
         else
            Error_Msg_N ("subtype mark required in this context", N);
            Set_Etype (N, Any_Type);
            return;
         end if;

         if T_Name = Any_Id or else Etype (N) = Any_Type then

            -- Undefined id. Make it into a valid type

            Set_Entity (N, Any_Type);

         elsif not Is_Type (T_Name)
           and then T_Name /= Standard_Void_Type
         then
            Error_Msg_Sloc := Sloc (T_Name);
            Error_Msg_N ("subtype mark required in this context", N);
            Error_Msg_NE ("\found & declared#", N, T_Name);
            Set_Entity (N, Any_Type);

         else
            T_Name := Get_Full_View (T_Name);

            if In_Open_Scopes (T_Name) then
               if Ekind (Base_Type (T_Name)) = E_Task_Type then
                  Error_Msg_N ("task type cannot be used as type mark " &
                     "within its own body", N);
               else
                  Error_Msg_N ("type declaration cannot refer to itself", N);
               end if;

               Set_Etype (N, Any_Type);
               Set_Entity (N, Any_Type);
               Set_Error_Posted (T_Name);
               return;
            end if;

            Set_Entity (N, T_Name);
            Set_Etype (N, T_Name);
         end if;
      end if;

      if Present (Etype (N)) and then Comes_From_Source (N) then
         if Is_Fixed_Point_Type (Etype (N)) then
            Check_Restriction (No_Fixed_Point, N);
         elsif Is_Floating_Point_Type (Etype (N)) then
            Check_Restriction (No_Floating_Point, N);
         end if;
      end if;
   end Find_Type;

   -------------------
   -- Get_Full_View --
   -------------------

   function Get_Full_View (T_Name : Entity_Id) return Entity_Id is
   begin
      if Ekind (T_Name) = E_Incomplete_Type
        and then Present (Full_View (T_Name))
      then
         return Full_View (T_Name);

      elsif Is_Class_Wide_Type (T_Name)
        and then Ekind (Root_Type (T_Name)) = E_Incomplete_Type
        and then Present (Full_View (Root_Type (T_Name)))
      then
         return Class_Wide_Type (Full_View (Root_Type (T_Name)));

      else
         return T_Name;
      end if;
   end Get_Full_View;

   ------------------------------------
   -- Has_Implicit_Character_Literal --
   ------------------------------------

   function Has_Implicit_Character_Literal (N : Node_Id) return Boolean is
      Id : Entity_Id;
      Found : Boolean := False;
      P : constant Entity_Id := Entity (Prefix (N));
      Priv_Id : Entity_Id := Empty;

   begin
      if Ekind (P) = E_Package
        and then not In_Open_Scopes (P)
      then
         Priv_Id := First_Private_Entity (P);
      end if;

      if P = Standard_Standard then
         Change_Selected_Component_To_Expanded_Name (N);
         Rewrite (N, Selector_Name (N));
         Analyze (N);
         Set_Etype (Original_Node (N), Standard_Character);
         return True;
      end if;

      Id := First_Entity (P);

      while Present (Id)
        and then Id /= Priv_Id
      loop
         if Is_Character_Type (Id)
           and then (Root_Type (Id) = Standard_Character
                       or else Root_Type (Id) = Standard_Wide_Character
                       or else Root_Type (Id) = Standard_Wide_Wide_Character)
           and then Id = Base_Type (Id)
         then
            -- We replace the node with the literal itself, resolve as a
            -- character, and set the type correctly.

            if not Found then
               Change_Selected_Component_To_Expanded_Name (N);
               Rewrite (N, Selector_Name (N));
               Analyze (N);
               Set_Etype (N, Id);
               Set_Etype (Original_Node (N), Id);
               Found := True;

            else
               -- More than one type derived from Character in given scope.
               -- Collect all possible interpretations.

               Add_One_Interp (N, Id, Id);
            end if;
         end if;

         Next_Entity (Id);
      end loop;

      return Found;
   end Has_Implicit_Character_Literal;

   ----------------------
   -- Has_Private_With --
   ----------------------

   function Has_Private_With (E : Entity_Id) return Boolean is
      Comp_Unit : constant Node_Id := Cunit (Current_Sem_Unit);
      Item : Node_Id;

   begin
      Item := First (Context_Items (Comp_Unit));
      while Present (Item) loop
         if Nkind (Item) = N_With_Clause
           and then Private_Present (Item)
           and then Entity (Name (Item)) = E
         then
            return True;
         end if;

         Next (Item);
      end loop;

      return False;
   end Has_Private_With;

   ---------------------------
   -- Has_Implicit_Operator --
   ---------------------------

   function Has_Implicit_Operator (N : Node_Id) return Boolean is
      Op_Id : constant Name_Id := Chars (Selector_Name (N));
      P : constant Entity_Id := Entity (Prefix (N));
      Id : Entity_Id;
      Priv_Id : Entity_Id := Empty;

      procedure Add_Implicit_Operator
        (T : Entity_Id;
         Op_Type : Entity_Id := Empty);
      -- Add implicit interpretation to node N, using the type for which
      -- a predefined operator exists. If the operator yields a boolean
      -- type, the Operand_Type is implicitly referenced by the operator,
      -- and a reference to it must be generated.

      ---------------------------
      -- Add_Implicit_Operator --
      ---------------------------

      procedure Add_Implicit_Operator
        (T : Entity_Id;
         Op_Type : Entity_Id := Empty)
      is
         Predef_Op : Entity_Id;

      begin
         Predef_Op := Current_Entity (Selector_Name (N));

         while Present (Predef_Op)
           and then Scope (Predef_Op) /= Standard_Standard
         loop
            Predef_Op := Homonym (Predef_Op);
         end loop;

         if Nkind (N) = N_Selected_Component then
            Change_Selected_Component_To_Expanded_Name (N);
         end if;

         Add_One_Interp (N, Predef_Op, T);

         -- For operators with unary and binary interpretations, add both

         if Present (Homonym (Predef_Op)) then
            Add_One_Interp (N, Homonym (Predef_Op), T);
         end if;

         -- The node is a reference to a predefined operator, and
         -- an implicit reference to the type of its operands.

         if Present (Op_Type) then
            Generate_Operator_Reference (N, Op_Type);
         else
            Generate_Operator_Reference (N, T);
         end if;
      end Add_Implicit_Operator;

   -- Start of processing for Has_Implicit_Operator

   begin

      if Ekind (P) = E_Package
        and then not In_Open_Scopes (P)
      then
         Priv_Id := First_Private_Entity (P);
      end if;

      Id := First_Entity (P);

      case Op_Id is

         -- Boolean operators: an implicit declaration exists if the scope
         -- contains a declaration for a derived Boolean type, or for an
         -- array of Boolean type.

         when Name_Op_And | Name_Op_Not | Name_Op_Or | Name_Op_Xor =>

            while Id /= Priv_Id loop

               if Valid_Boolean_Arg (Id)
                 and then Id = Base_Type (Id)
               then
                  Add_Implicit_Operator (Id);
                  return True;
               end if;

               Next_Entity (Id);
            end loop;

         -- Equality: look for any non-limited type (result is Boolean)

         when Name_Op_Eq | Name_Op_Ne =>

            while Id /= Priv_Id loop

               if Is_Type (Id)
                 and then not Is_Limited_Type (Id)
                 and then Id = Base_Type (Id)
               then
                  Add_Implicit_Operator (Standard_Boolean, Id);
                  return True;
               end if;

               Next_Entity (Id);
            end loop;

         -- Comparison operators: scalar type, or array of scalar

         when Name_Op_Lt | Name_Op_Le | Name_Op_Gt | Name_Op_Ge =>

            while Id /= Priv_Id loop
               if (Is_Scalar_Type (Id)
                 or else (Is_Array_Type (Id)
                           and then Is_Scalar_Type (Component_Type (Id))))
                 and then Id = Base_Type (Id)
               then
                  Add_Implicit_Operator (Standard_Boolean, Id);
                  return True;
               end if;

               Next_Entity (Id);
            end loop;

         -- Arithmetic operators: any numeric type

         when Name_Op_Abs |
              Name_Op_Add |
              Name_Op_Mod |
              Name_Op_Rem |
              Name_Op_Subtract |
              Name_Op_Multiply |
              Name_Op_Divide |
              Name_Op_Expon =>

            while Id /= Priv_Id loop
               if Is_Numeric_Type (Id)
                 and then Id = Base_Type (Id)
               then
                  Add_Implicit_Operator (Id);
                  return True;
               end if;

               Next_Entity (Id);
            end loop;

         -- Concatenation: any one-dimensional array type

         when Name_Op_Concat =>

            while Id /= Priv_Id loop
               if Is_Array_Type (Id) and then Number_Dimensions (Id) = 1
                 and then Id = Base_Type (Id)
               then
                  Add_Implicit_Operator (Id);
                  return True;
               end if;

               Next_Entity (Id);
            end loop;

         -- What is the others condition here? Should we be using a
         -- subtype of Name_Id that would restrict to operators ???

         when others => null;

      end case;

      -- If we fall through, then we do not have an implicit operator

      return False;

   end Has_Implicit_Operator;

   --------------------
   -- In_Open_Scopes --
   --------------------

   function In_Open_Scopes (S : Entity_Id) return Boolean is
   begin
      -- Since there are several scope stacks maintained by Scope_Stack each
      -- delineated by Standard (see comments by definition of Scope_Stack)
      -- it is necessary to end the search when Standard is reached.

      for J in reverse 0 .. Scope_Stack.Last loop
         if Scope_Stack.Table (J).Entity = S then
            return True;
         end if;

         -- We need Is_Active_Stack_Base to tell us when to stop rather
         -- than checking for Standard_Standard because there are cases
         -- where Standard_Standard appears in the middle of the active
         -- set of scopes. This affects the declaration and overriding
         -- of private inherited operations in instantiations of generic
         -- child units.

         exit when Scope_Stack.Table (J).Is_Active_Stack_Base;
      end loop;

      return False;
   end In_Open_Scopes;

   -----------------------------
   -- Inherit_Renamed_Profile --
   -----------------------------

   procedure Inherit_Renamed_Profile (New_S : Entity_Id; Old_S : Entity_Id) is
      New_F : Entity_Id;
      Old_F : Entity_Id;
      Old_T : Entity_Id;
      New_T : Entity_Id;

   begin
      if Ekind (Old_S) = E_Operator then

         New_F := First_Formal (New_S);

         while Present (New_F) loop
            Set_Etype (New_F, Base_Type (Etype (New_F)));
            Next_Formal (New_F);
         end loop;

         Set_Etype (New_S, Base_Type (Etype (New_S)));

      else
         New_F := First_Formal (New_S);
         Old_F := First_Formal (Old_S);

         while Present (New_F) loop
            New_T := Etype (New_F);
            Old_T := Etype (Old_F);

            -- If the new type is a renaming of the old one, as is the
            -- case for actuals in instances, retain its name, to simplify
            -- later disambiguation.

            if Nkind (Parent (New_T)) = N_Subtype_Declaration
              and then Is_Entity_Name (Subtype_Indication (Parent (New_T)))
              and then Entity (Subtype_Indication (Parent (New_T))) = Old_T
            then
               null;
            else
               Set_Etype (New_F, Old_T);
            end if;

            Next_Formal (New_F);
            Next_Formal (Old_F);
         end loop;

         if Ekind (Old_S) = E_Function
           or else Ekind (Old_S) = E_Enumeration_Literal
         then
            Set_Etype (New_S, Etype (Old_S));
         end if;
      end if;
   end Inherit_Renamed_Profile;

   ----------------
   -- Initialize --
   ----------------

   procedure Initialize is
   begin
      Urefs.Init;
   end Initialize;

   -------------------------
   -- Install_Use_Clauses --
   -------------------------

   procedure Install_Use_Clauses
     (Clause : Node_Id;
      Force_Installation : Boolean := False)
   is
      U : Node_Id := Clause;
      P : Node_Id;
      Id : Entity_Id;

   begin
      while Present (U) loop

         -- Case of USE package

         if Nkind (U) = N_Use_Package_Clause then
            P := First (Names (U));

            while Present (P) loop
               Id := Entity (P);

               if Ekind (Id) = E_Package then

                  if In_Use (Id) then
                     Note_Redundant_Use (P);

                  elsif Present (Renamed_Object (Id))
                    and then In_Use (Renamed_Object (Id))
                  then
                     Note_Redundant_Use (P);

                  elsif Force_Installation or else Applicable_Use (P) then
                     Use_One_Package (Id, U);

                  end if;
               end if;

               Next (P);
            end loop;

         -- case of USE TYPE

         else
            P := First (Subtype_Marks (U));

            while Present (P) loop
               if not Is_Entity_Name (P)
                 or else No (Entity (P))
               then
                  null;

               elsif Entity (P) /= Any_Type then
                  Use_One_Type (P);
               end if;

               Next (P);
            end loop;
         end if;

         Next_Use_Clause (U);
      end loop;
   end Install_Use_Clauses;

   -------------------------------------
   -- Is_Appropriate_For_Entry_Prefix --
   -------------------------------------

   function Is_Appropriate_For_Entry_Prefix (T : Entity_Id) return Boolean is
      P_Type : Entity_Id := T;

   begin
      if Is_Access_Type (P_Type) then
         P_Type := Designated_Type (P_Type);
      end if;

      return Is_Task_Type (P_Type) or else Is_Protected_Type (P_Type);
   end Is_Appropriate_For_Entry_Prefix;

   -------------------------------
   -- Is_Appropriate_For_Record --
   -------------------------------

   function Is_Appropriate_For_Record (T : Entity_Id) return Boolean is

      function Has_Components (T1 : Entity_Id) return Boolean;
      -- Determine if given type has components (i.e. is either a record
      -- type or a type that has discriminants).

      function Has_Components (T1 : Entity_Id) return Boolean is
      begin
         return Is_Record_Type (T1)
           or else (Is_Private_Type (T1) and then Has_Discriminants (T1))
           or else (Is_Task_Type (T1) and then Has_Discriminants (T1));
      end Has_Components;

   -- Start of processing for Is_Appropriate_For_Record

   begin
      return
        Present (T)
          and then (Has_Components (T)
                      or else (Is_Access_Type (T)
                                 and then
                                   Has_Components (Designated_Type (T))));
   end Is_Appropriate_For_Record;

   ---------------
   -- New_Scope --
   ---------------

   procedure New_Scope (S : Entity_Id) is
      E : Entity_Id;

   begin
      if Ekind (S) = E_Void then
         null;

      -- Set scope depth if not a non-concurrent type, and we have not
      -- yet set the scope depth. This means that we have the first
      -- occurrence of the scope, and this is where the depth is set.

      elsif (not Is_Type (S) or else Is_Concurrent_Type (S))
        and then not Scope_Depth_Set (S)
      then
         if S = Standard_Standard then
            Set_Scope_Depth_Value (S, Uint_0);

         elsif Is_Child_Unit (S) then
            Set_Scope_Depth_Value (S, Uint_1);

         elsif not Is_Record_Type (Current_Scope) then
            if Ekind (S) = E_Loop then
               Set_Scope_Depth_Value (S, Scope_Depth (Current_Scope));
            else
               Set_Scope_Depth_Value (S, Scope_Depth (Current_Scope) + 1);
            end if;
         end if;
      end if;

      Scope_Stack.Increment_Last;

      declare
         SST : Scope_Stack_Entry renames Scope_Stack.Table (Scope_Stack.Last);

      begin
         SST.Entity := S;
         SST.Save_Scope_Suppress := Scope_Suppress;
         SST.Save_Local_Entity_Suppress := Local_Entity_Suppress.Last;

         if Scope_Stack.Last > Scope_Stack.First then
            SST.Component_Alignment_Default := Scope_Stack.Table
                                                 (Scope_Stack.Last - 1).
                                                   Component_Alignment_Default;
         end if;

         SST.Last_Subprogram_Name := null;
         SST.Is_Transient := False;
         SST.Node_To_Be_Wrapped := Empty;
         SST.Pending_Freeze_Actions := No_List;
         SST.Actions_To_Be_Wrapped_Before := No_List;
         SST.Actions_To_Be_Wrapped_After := No_List;
         SST.First_Use_Clause := Empty;
         SST.Is_Active_Stack_Base := False;
      end;

      if Debug_Flag_W then
         Write_Str ("--> new scope: ");
         Write_Name (Chars (Current_Scope));
         Write_Str (", Id=");
         Write_Int (Int (Current_Scope));
         Write_Str (", Depth=");
         Write_Int (Int (Scope_Stack.Last));
         Write_Eol;
      end if;

      -- Copy from Scope (S) the categorization flags to S, this is not
      -- done in case Scope (S) is Standard_Standard since propagation
      -- is from library unit entity inwards.

      if S /= Standard_Standard
        and then Scope (S) /= Standard_Standard
        and then not Is_Child_Unit (S)
      then
         E := Scope (S);

         if Nkind (E) not in N_Entity then
            return;
         end if;

         -- We only propagate inwards for library level entities,
         -- inner level subprograms do not inherit the categorization.

         if Is_Library_Level_Entity (S) then
            Set_Is_Preelaborated (S, Is_Preelaborated (E));
            Set_Is_Shared_Passive (S, Is_Shared_Passive (E));
            Set_Categorization_From_Scope (E => S, Scop => E);
         end if;
      end if;
   end New_Scope;

   ------------------------
   -- Note_Redundant_Use --
   ------------------------

   procedure Note_Redundant_Use (Clause : Node_Id) is
      Pack_Name : constant Entity_Id := Entity (Clause);
      Cur_Use : constant Node_Id := Current_Use_Clause (Pack_Name);
      Decl : constant Node_Id := Parent (Clause);

      Prev_Use : Node_Id := Empty;
      Redundant : Node_Id := Empty;
      -- The Use_Clause which is actually redundant. In the simplest case
      -- it is Pack itself, but when we compile a body we install its
      -- context before that of its spec, in which case it is the use_clause
      -- in the spec that will appear to be redundant, and we want the
      -- warning to be placed on the body. Similar complications appear when
      -- the redundancy is between a child unit and one of its ancestors.

   begin
      Set_Redundant_Use (Clause, True);

      if not Comes_From_Source (Clause)
        or else In_Instance
        or else not Warn_On_Redundant_Constructs
      then
         return;
      end if;

      if not Is_Compilation_Unit (Current_Scope) then

         -- If the use_clause is in an inner scope, it is made redundant
         -- by some clause in the current context.

         Redundant := Clause;
         Prev_Use := Cur_Use;

      elsif Nkind (Unit (Cunit (Current_Sem_Unit))) = N_Package_Body then
         declare
            Cur_Unit : constant Unit_Number_Type := Get_Source_Unit (Cur_Use);
            New_Unit : constant Unit_Number_Type := Get_Source_Unit (Clause);
            Scop : Entity_Id;

         begin
            if Cur_Unit = New_Unit then

               -- Redundant clause in same body

               Redundant := Clause;
               Prev_Use := Cur_Use;

            elsif Cur_Unit = Current_Sem_Unit then

               -- If the new clause is not in the current unit it has been
               -- analyzed first, and it makes the other one redundant.
               -- However, if the new clause appears in a subunit, Cur_Unit
               -- is still the parent, and in that case the redundant one
               -- is the one appearing in the subunit.

               if Nkind (Unit (Cunit (New_Unit))) = N_Subunit then
                  Redundant := Clause;
                  Prev_Use := Cur_Use;

               -- Most common case: redundant clause in body,
               -- original clause in spec. Current scope is spec entity.

               elsif
                 Current_Scope =
                   Defining_Entity (
                     Unit (Library_Unit (Cunit (Current_Sem_Unit))))
               then
                  Redundant := Cur_Use;
                  Prev_Use := Clause;

               else
                  -- The new clause may appear in an unrelated unit, when
                  -- the parents of a generic are being installed prior to
                  -- instantiation. In this case there must be no warning.
                  -- We detect this case by checking whether the current top
                  -- of the stack is related to the current compilation.

                  Scop := Current_Scope;
                  while Present (Scop)
                    and then Scop /= Standard_Standard
                  loop
                     if Is_Compilation_Unit (Scop)
                       and then not Is_Child_Unit (Scop)
                     then
                        return;

                     elsif Scop = Cunit_Entity (Current_Sem_Unit) then
                        exit;
                     end if;

                     Scop := Scope (Scop);
                  end loop;

                  Redundant := Cur_Use;
                  Prev_Use := Clause;
               end if;

            elsif New_Unit = Current_Sem_Unit then
               Redundant := Clause;
               Prev_Use := Cur_Use;

            else
               -- Neither is the current unit, so they appear in parent or
               -- sibling units. Warning will be emitted elsewhere.

               return;
            end if;
         end;

      elsif Nkind (Unit (Cunit (Current_Sem_Unit))) = N_Package_Declaration
        and then Present (Parent_Spec (Unit (Cunit (Current_Sem_Unit))))
      then
         -- Use_clause is in child unit of current unit, and the child
         -- unit appears in the context of the body of the parent, so it
         -- has been installed first, even though it is the redundant one.
         -- Depending on their placement in the context, the visible or the
         -- private parts of the two units, either might appear as redundant,
         -- but the message has to be on the current unit.

         if Get_Source_Unit (Cur_Use) = Current_Sem_Unit then
            Redundant := Cur_Use;
            Prev_Use := Clause;
         else
            Redundant := Clause;
            Prev_Use := Cur_Use;
         end if;

         -- If the new use clause appears in the private part of a parent unit
         -- it may appear to be redudant w.r.t. a use clause in a child unit,
         -- but the previous use clause was needed in the visible part of the
         -- child, and no warning should be emitted.

         if Nkind (Parent (Decl)) = N_Package_Specification
           and then
             List_Containing (Decl) = Private_Declarations (Parent (Decl))
         then
            declare
               Par : constant Entity_Id := Defining_Entity (Parent (Decl));
               Spec : constant Node_Id :=
                        Specification (Unit (Cunit (Current_Sem_Unit)));

            begin
               if Is_Compilation_Unit (Par)
                 and then Par /= Cunit_Entity (Current_Sem_Unit)
                 and then Parent (Cur_Use) = Spec
                 and then
                   List_Containing (Cur_Use) = Visible_Declarations (Spec)
               then
                  return;
               end if;
            end;
         end if;

      else
         null;
      end if;

      if Present (Redundant) then
         Error_Msg_Sloc := Sloc (Prev_Use);
         Error_Msg_NE (
           "& is already use_visible through declaration #?",
              Redundant, Pack_Name);
      end if;
   end Note_Redundant_Use;

   ---------------
   -- Pop_Scope --
   ---------------

   procedure Pop_Scope is
      SST : Scope_Stack_Entry renames Scope_Stack.Table (Scope_Stack.Last);

   begin
      if Debug_Flag_E then
         Write_Info;
      end if;

      Scope_Suppress := SST.Save_Scope_Suppress;
      Local_Entity_Suppress.Set_Last (SST.Save_Local_Entity_Suppress);

      if Debug_Flag_W then
         Write_Str ("--> exiting scope: ");
         Write_Name (Chars (Current_Scope));
         Write_Str (", Depth=");
         Write_Int (Int (Scope_Stack.Last));
         Write_Eol;
      end if;

      End_Use_Clauses (SST.First_Use_Clause);

      -- If the actions to be wrapped are still there they will get lost
      -- causing incomplete code to be generated. It is better to abort in
      -- this case (and we do the abort even with assertions off since the
      -- penalty is incorrect code generation)

      if SST.Actions_To_Be_Wrapped_Before /= No_List
           or else
         SST.Actions_To_Be_Wrapped_After /= No_List
      then
         return;
      end if;

      -- Free last subprogram name if allocated, and pop scope

      Free (SST.Last_Subprogram_Name);
      Scope_Stack.Decrement_Last;
   end Pop_Scope;

   ---------------------
   -- Premature_Usage --
   ---------------------

   procedure Premature_Usage (N : Node_Id) is
      Kind : constant Node_Kind := Nkind (Parent (Entity (N)));
      E : Entity_Id := Entity (N);

   begin
      -- Within an instance, the analysis of the actual for a formal object
      -- does not see the name of the object itself. This is significant
      -- only if the object is an aggregate, where its analysis does not do
      -- any name resolution on component associations. (see 4717-008). In
      -- such a case, look for the visible homonym on the chain.

      if In_Instance
        and then Present (Homonym (E))
      then
         E := Homonym (E);

         while Present (E)
           and then not In_Open_Scopes (Scope (E))
         loop
            E := Homonym (E);
         end loop;

         if Present (E) then
            Set_Entity (N, E);
            Set_Etype (N, Etype (E));
            return;
         end if;
      end if;

      if Kind = N_Component_Declaration then
         Error_Msg_N
           ("component&! cannot be used before end of record declaration", N);

      elsif Kind = N_Parameter_Specification then
         Error_Msg_N
           ("formal parameter&! cannot be used before end of specification",
            N);

      elsif Kind = N_Discriminant_Specification then
         Error_Msg_N
           ("discriminant&! cannot be used before end of discriminant part",
            N);

      elsif Kind = N_Procedure_Specification
        or else Kind = N_Function_Specification
      then
         Error_Msg_N
           ("subprogram&! cannot be used before end of its declaration",
            N);
      else
         Error_Msg_N
           ("object& cannot be used before end of its declaration!", N);
      end if;
   end Premature_Usage;

   ------------------------
   -- Present_System_Aux --
   ------------------------

   function Present_System_Aux (N : Node_Id := Empty) return Boolean is
      Loc : Source_Ptr;
      Aux_Name : Name_Id;
      Unum : Unit_Number_Type;
      Withn : Node_Id;
      With_Sys : Node_Id;
      The_Unit : Node_Id;

      function Find_System (C_Unit : Node_Id) return Entity_Id;
      -- Scan context clause of compilation unit to find a with_clause
      -- for System.

      -----------------
      -- Find_System --
      -----------------

      function Find_System (C_Unit : Node_Id) return Entity_Id is
         With_Clause : Node_Id;

      begin
         With_Clause := First (Context_Items (C_Unit));

         while Present (With_Clause) loop
            if (Nkind (With_Clause) = N_With_Clause
              and then Chars (Name (With_Clause)) = Name_System)
              and then Comes_From_Source (With_Clause)
            then
               return With_Clause;
            end if;

            Next (With_Clause);
         end loop;

         return Empty;
      end Find_System;

   -- Start of processing for Present_System_Aux

   begin
      -- The child unit may have been loaded and analyzed already

      if Present (System_Aux_Id) then
         return True;

      -- If no previous pragma for System.Aux, nothing to load

      elsif No (System_Extend_Unit) then
         return False;

      -- Use the unit name given in the pragma to retrieve the unit.
      -- Verify that System itself appears in the context clause of the
      -- current compilation. If System is not present, an error will
      -- have been reported already.

      else
         With_Sys := Find_System (Cunit (Current_Sem_Unit));

         The_Unit := Unit (Cunit (Current_Sem_Unit));

         if No (With_Sys)
           and then (Nkind (The_Unit) = N_Package_Body
                      or else (Nkind (The_Unit) = N_Subprogram_Body
                        and then not Acts_As_Spec (Cunit (Current_Sem_Unit))))
         then
            With_Sys := Find_System (Library_Unit (Cunit (Current_Sem_Unit)));
         end if;

         if No (With_Sys)
           and then Present (N)
         then
            -- If we are compiling a subunit, we need to examine its
            -- context as well (Current_Sem_Unit is the parent unit);

            The_Unit := Parent (N);

            while Nkind (The_Unit) /= N_Compilation_Unit loop
               The_Unit := Parent (The_Unit);
            end loop;

            if Nkind (Unit (The_Unit)) = N_Subunit then
               With_Sys := Find_System (The_Unit);
            end if;
         end if;

         if No (With_Sys) then
            return False;
         end if;

         Loc := Sloc (With_Sys);
         Get_Name_String (Chars (Expression (System_Extend_Unit)));
         Name_Buffer (8 .. Name_Len + 7) := Name_Buffer (1 .. Name_Len);
         Name_Buffer (1 .. 7) := "system.";
         Name_Buffer (Name_Len + 8) := '%';
         Name_Buffer (Name_Len + 9) := 's';
         Name_Len := Name_Len + 9;
         Aux_Name := Name_Find;

         Unum :=
           Load_Unit
             (Load_Name => Aux_Name,
              Required => False,
              Subunit => False,
              Error_Node => With_Sys);

         if Unum /= No_Unit then
            Semantics (Cunit (Unum));
            System_Aux_Id :=
              Defining_Entity (Specification (Unit (Cunit (Unum))));

            Withn := Make_With_Clause (Loc,
              Name =>
                Make_Expanded_Name (Loc,
                  Chars => Chars (System_Aux_Id),
                  Prefix =>
                    New_Reference_To (Scope (System_Aux_Id), Loc),
                  Selector_Name =>
                    New_Reference_To (System_Aux_Id, Loc)));

            Set_Entity (Name (Withn), System_Aux_Id);

            Set_Library_Unit (Withn, Cunit (Unum));
            Set_Corresponding_Spec (Withn, System_Aux_Id);
            Set_First_Name (Withn, True);
            Set_Implicit_With (Withn, True);

            Insert_After (With_Sys, Withn);
            Mark_Rewrite_Insertion (Withn);
            Set_Context_Installed (Withn);

            return True;

         -- Here if unit load failed

         else
            Error_Msg_Name_1 := Name_System;
            Error_Msg_Name_2 := Chars (Expression (System_Extend_Unit));
            Error_Msg_N
              ("extension package `%.%` does not exist",
               Opt.System_Extend_Unit);
            return False;
         end if;
      end if;
   end Present_System_Aux;

   -------------------------
   -- Restore_Scope_Stack --
   -------------------------

   procedure Restore_Scope_Stack (Handle_Use : Boolean := True) is
      E : Entity_Id;
      S : Entity_Id;
      Comp_Unit : Node_Id;
      In_Child : Boolean := False;
      Full_Vis : Boolean := True;
      SS_Last : constant Int := Scope_Stack.Last;

   begin
      -- Restore visibility of previous scope stack, if any

      for J in reverse 0 .. Scope_Stack.Last loop
         exit when Scope_Stack.Table (J).Entity = Standard_Standard
            or else No (Scope_Stack.Table (J).Entity);

         S := Scope_Stack.Table (J).Entity;

         if not Is_Hidden_Open_Scope (S) then

            -- If the parent scope is hidden, its entities are hidden as
            -- well, unless the entity is the instantiation currently
            -- being analyzed.

            if not Is_Hidden_Open_Scope (Scope (S))
              or else not Analyzed (Parent (S))
              or else Scope (S) = Standard_Standard
            then
               Set_Is_Immediately_Visible (S, True);
            end if;

            E := First_Entity (S);

            while Present (E) loop
               if Is_Child_Unit (E) then
                  Set_Is_Immediately_Visible (E,
                    Is_Visible_Child_Unit (E) or else In_Open_Scopes (E));
               else
                  Set_Is_Immediately_Visible (E, True);
               end if;

               Next_Entity (E);

               if not Full_Vis then
                  exit when E = First_Private_Entity (S);
               end if;
            end loop;

            -- The visibility of child units (siblings of current compilation)
            -- must be restored in any case. Their declarations may appear
            -- after the private part of the parent.

            if not Full_Vis
              and then Present (E)
            then
               while Present (E) loop
                  if Is_Child_Unit (E) then
                     Set_Is_Immediately_Visible (E,
                       Is_Visible_Child_Unit (E) or else In_Open_Scopes (E));
                  end if;

                  Next_Entity (E);
               end loop;
            end if;
         end if;

         if Is_Child_Unit (S)
            and not In_Child -- check only for current unit.
         then
            In_Child := True;

            -- restore visibility of parents according to whether the child
            -- is private and whether we are in its visible part.

            Comp_Unit := Parent (Unit_Declaration_Node (S));

            if Nkind (Comp_Unit) = N_Compilation_Unit
              and then Private_Present (Comp_Unit)
            then
               Full_Vis := True;

            elsif (Ekind (S) = E_Package
                    or else Ekind (S) = E_Generic_Package)
              and then (In_Private_Part (S)
                         or else In_Package_Body (S))
            then
               Full_Vis := True;

            elsif (Ekind (S) = E_Procedure
                    or else Ekind (S) = E_Function)
              and then Has_Completion (S)
            then
               Full_Vis := True;
            else
               Full_Vis := False;
            end if;
         else
            Full_Vis := True;
         end if;
      end loop;

      if SS_Last >= Scope_Stack.First
        and then Scope_Stack.Table (SS_Last).Entity /= Standard_Standard
        and then Handle_Use
      then
         Install_Use_Clauses (Scope_Stack.Table (SS_Last).First_Use_Clause);
      end if;
   end Restore_Scope_Stack;

   ----------------------
   -- Save_Scope_Stack --
   ----------------------

   procedure Save_Scope_Stack (Handle_Use : Boolean := True) is
      E : Entity_Id;
      S : Entity_Id;
      SS_Last : constant Int := Scope_Stack.Last;

   begin
      if SS_Last >= Scope_Stack.First
        and then Scope_Stack.Table (SS_Last).Entity /= Standard_Standard
      then
         if Handle_Use then
            End_Use_Clauses (Scope_Stack.Table (SS_Last).First_Use_Clause);
         end if;

         -- If the call is from within a compilation unit, as when
         -- called from Rtsfind, make current entries in scope stack
         -- invisible while we analyze the new unit.

         for J in reverse 0 .. SS_Last loop
            exit when Scope_Stack.Table (J).Entity = Standard_Standard
               or else No (Scope_Stack.Table (J).Entity);

            S := Scope_Stack.Table (J).Entity;
            Set_Is_Immediately_Visible (S, False);
            E := First_Entity (S);

            while Present (E) loop
               Set_Is_Immediately_Visible (E, False);
               Next_Entity (E);
            end loop;
         end loop;

      end if;
   end Save_Scope_Stack;

   -------------
   -- Set_Use --
   -------------

   procedure Set_Use (L : List_Id) is
      Decl : Node_Id;
      Pack_Name : Node_Id;
      Pack : Entity_Id;
      Id : Entity_Id;

   begin
      if Present (L) then
         Decl := First (L);

         while Present (Decl) loop
            if Nkind (Decl) = N_Use_Package_Clause then
               Chain_Use_Clause (Decl);
               Pack_Name := First (Names (Decl));

               while Present (Pack_Name) loop
                  Pack := Entity (Pack_Name);

                  if Ekind (Pack) = E_Package
                    and then Applicable_Use (Pack_Name)
                  then
                     Use_One_Package (Pack, Decl);
                  end if;

                  Next (Pack_Name);
               end loop;

            elsif Nkind (Decl) = N_Use_Type_Clause then
               Chain_Use_Clause (Decl);
               Id := First (Subtype_Marks (Decl));

               while Present (Id) loop
                  if Entity (Id) /= Any_Type then
                     Use_One_Type (Id);
                  end if;

                  Next (Id);
               end loop;
            end if;

            Next (Decl);
         end loop;
      end if;
   end Set_Use;

   ---------------------
   -- Use_One_Package --
   ---------------------

   procedure Use_One_Package (P : Entity_Id; N : Node_Id) is
      Id : Entity_Id;
      Prev : Entity_Id;
      Current_Instance : Entity_Id := Empty;
      Real_P : Entity_Id;
      Private_With_OK : Boolean := False;

   begin
      if Ekind (P) /= E_Package then
         return;
      end if;

      Set_In_Use (P);
      Set_Current_Use_Clause (P, N);

      -- Ada 2005 (AI-50217): Check restriction

      if From_With_Type (P) then
         Error_Msg_N ("limited withed package cannot appear in use clause", N);
      end if;

      -- Find enclosing instance, if any

      if In_Instance then
         Current_Instance := Current_Scope;

         while not Is_Generic_Instance (Current_Instance) loop
            Current_Instance := Scope (Current_Instance);
         end loop;

         if No (Hidden_By_Use_Clause (N)) then
            Set_Hidden_By_Use_Clause (N, New_Elmt_List);
         end if;
      end if;

      -- If unit is a package renaming, indicate that the renamed
      -- package is also in use (the flags on both entities must
      -- remain consistent, and a subsequent use of either of them
      -- should be recognized as redundant).

      if Present (Renamed_Object (P)) then
         Set_In_Use (Renamed_Object (P));
         Set_Current_Use_Clause (Renamed_Object (P), N);
         Real_P := Renamed_Object (P);
      else
         Real_P := P;
      end if;

      -- Ada 2005 (AI-262): Check the use_clause of a private withed package
      -- found in the private part of a package specification

      if In_Private_Part (Current_Scope)
        and then Has_Private_With (P)
        and then Is_Child_Unit (Current_Scope)
        and then Is_Child_Unit (P)
        and then Is_Ancestor_Package (Scope (Current_Scope), P)
      then
         Private_With_OK := True;
      end if;

      -- Loop through entities in one package making them potentially
      -- use-visible.

      Id := First_Entity (P);
      while Present (Id)
        and then (Id /= First_Private_Entity (P)
                    or else Private_With_OK) -- Ada 2005 (AI-262)
      loop
         Prev := Current_Entity (Id);

         while Present (Prev) loop
            if Is_Immediately_Visible (Prev)
              and then (not Is_Overloadable (Prev)
                         or else not Is_Overloadable (Id)
                         or else (Type_Conformant (Id, Prev)))
            then
               if No (Current_Instance) then

                  -- Potentially use-visible entity remains hidden

                  goto Next_Usable_Entity;

               -- A use clause within an instance hides outer global
               -- entities, which are not used to resolve local entities
               -- in the instance. Note that the predefined entities in
               -- Standard could not have been hidden in the generic by
               -- a use clause, and therefore remain visible. Other
               -- compilation units whose entities appear in Standard must
               -- be hidden in an instance.

               -- To determine whether an entity is external to the instance
               -- we compare the scope depth of its scope with that of the
               -- current instance. However, a generic actual of a subprogram
               -- instance is declared in the wrapper package but will not be
               -- hidden by a use-visible entity.

               -- If Id is called Standard, the predefined package with the
               -- same name is in the homonym chain. It has to be ignored
               -- because it has no defined scope (being the only entity in
               -- the system with this mandated behavior).

               elsif not Is_Hidden (Id)
                 and then Present (Scope (Prev))
                 and then not Is_Wrapper_Package (Scope (Prev))
                 and then Scope_Depth (Scope (Prev)) <
                          Scope_Depth (Current_Instance)
                 and then (Scope (Prev) /= Standard_Standard
                            or else Sloc (Prev) > Standard_Location)
               then
                  Set_Is_Potentially_Use_Visible (Id);
                  Set_Is_Immediately_Visible (Prev, False);
                  Append_Elmt (Prev, Hidden_By_Use_Clause (N));
               end if;

            -- A user-defined operator is not use-visible if the
            -- predefined operator for the type is immediately visible,
            -- which is the case if the type of the operand is in an open
            -- scope. This does not apply to user-defined operators that
            -- have operands of different types, because the predefined
            -- mixed mode operations (multiplication and division) apply to
            -- universal types and do not hide anything.

            elsif Ekind (Prev) = E_Operator
              and then Operator_Matches_Spec (Prev, Id)
              and then In_Open_Scopes
               (Scope (Base_Type (Etype (First_Formal (Id)))))
              and then (No (Next_Formal (First_Formal (Id)))
                         or else Etype (First_Formal (Id))
                           = Etype (Next_Formal (First_Formal (Id)))
                         or else Chars (Prev) = Name_Op_Expon)
            then
               goto Next_Usable_Entity;
            end if;

            Prev := Homonym (Prev);
         end loop;

         -- On exit, we know entity is not hidden, unless it is private

         if not Is_Hidden (Id)
           and then ((not Is_Child_Unit (Id))
                       or else Is_Visible_Child_Unit (Id))
         then
            Set_Is_Potentially_Use_Visible (Id);

            if Is_Private_Type (Id)
              and then Present (Full_View (Id))
            then
               Set_Is_Potentially_Use_Visible (Full_View (Id));
            end if;
         end if;

         <<Next_Usable_Entity>>
            Next_Entity (Id);
      end loop;

      -- Child units are also made use-visible by a use clause, but they
      -- may appear after all visible declarations in the parent entity list.

      while Present (Id) loop

         if Is_Child_Unit (Id)
           and then Is_Visible_Child_Unit (Id)
         then
            Set_Is_Potentially_Use_Visible (Id);
         end if;

         Next_Entity (Id);
      end loop;

      if Chars (Real_P) = Name_System
        and then Scope (Real_P) = Standard_Standard
        and then Present_System_Aux (N)
      then
         Use_One_Package (System_Aux_Id, N);
      end if;

   end Use_One_Package;

   ------------------
   -- Use_One_Type --
   ------------------

   procedure Use_One_Type (Id : Node_Id) is
      T : Entity_Id;
      Op_List : Elist_Id;
      Elmt : Elmt_Id;

   begin
      -- It is the type determined by the subtype mark (8.4(8)) whose
      -- operations become potentially use-visible.

      T := Base_Type (Entity (Id));

      Set_Redundant_Use
        (Id,
           In_Use (T)
             or else Is_Potentially_Use_Visible (T)
             or else In_Use (Scope (T)));

      if In_Open_Scopes (Scope (T)) then
         null;

      -- If the subtype mark designates a subtype in a different package,
      -- we have to check that the parent type is visible, otherwise the
      -- use type clause is a noop. Not clear how to do that???

      elsif not Redundant_Use (Id) then
         Set_In_Use (T);
         Op_List := Collect_Primitive_Operations (T);
         Elmt := First_Elmt (Op_List);

         while Present (Elmt) loop

            if (Nkind (Node (Elmt)) = N_Defining_Operator_Symbol
                 or else Chars (Node (Elmt)) in Any_Operator_Name)
              and then not Is_Hidden (Node (Elmt))
            then
               Set_Is_Potentially_Use_Visible (Node (Elmt));
            end if;

            Next_Elmt (Elmt);
         end loop;
      end if;
   end Use_One_Type;

   ----------------
   -- Write_Info --
   ----------------

   procedure Write_Info is
      Id : Entity_Id := First_Entity (Current_Scope);

   begin
      -- No point in dumping standard entities

      if Current_Scope = Standard_Standard then
         return;
      end if;

      Write_Str ("========================================================");
      Write_Eol;
      Write_Str (" Defined Entities in ");
      Write_Name (Chars (Current_Scope));
      Write_Eol;
      Write_Str ("========================================================");
      Write_Eol;

      if No (Id) then
         Write_Str ("-- none --");
         Write_Eol;

      else
         while Present (Id) loop
            Write_Entity_Info (Id, " ");
            Next_Entity (Id);
         end loop;
      end if;

      if Scope (Current_Scope) = Standard_Standard then

         -- Print information on the current unit itself

         Write_Entity_Info (Current_Scope, " ");
      end if;

      Write_Eol;
   end Write_Info;

   -----------------
   -- Write_Scopes --
   -----------------

   procedure Write_Scopes is
      S : Entity_Id;

   begin
      for J in reverse 1 .. Scope_Stack.Last loop
         S := Scope_Stack.Table (J).Entity;
         Write_Int (Int (S));
         Write_Str (" === ");
         Write_Name (Chars (S));
         Write_Eol;
      end loop;
   end Write_Scopes;

end Sem_Ch8;

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Received on Sun May 21 22:16:53 2006

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