205 lines
11 KiB
Ada
205 lines
11 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- S E M _ C H 8 --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 1992-2020, Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
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-- for more details. You should have received a copy of the GNU General --
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-- Public License distributed with GNAT; see file COPYING3. If not, go to --
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-- http://www.gnu.org/licenses for a complete copy of the license. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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with Types; use Types;
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package Sem_Ch8 is
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-----------------------------------
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-- Handling extensions of System --
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-----------------------------------
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-- For targets that define a much larger System package than given in
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-- the RM, we use a child package containing additional declarations,
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-- which is loaded when needed, and whose entities are conceptually
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-- within System itself. The presence of this auxiliary package is
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-- controlled with the pragma Extend_System. The following variable
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-- holds the entity of the auxiliary package, to simplify the special
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-- visibility rules that apply to it.
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System_Aux_Id : Entity_Id := Empty;
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-----------------
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-- Subprograms --
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-----------------
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procedure Analyze_Exception_Renaming (N : Node_Id);
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procedure Analyze_Expanded_Name (N : Node_Id);
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procedure Analyze_Generic_Function_Renaming (N : Node_Id);
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procedure Analyze_Generic_Package_Renaming (N : Node_Id);
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procedure Analyze_Generic_Procedure_Renaming (N : Node_Id);
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procedure Analyze_Object_Renaming (N : Node_Id);
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procedure Analyze_Package_Renaming (N : Node_Id);
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procedure Analyze_Subprogram_Renaming (N : Node_Id);
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procedure Analyze_Use_Package (N : Node_Id; Chain : Boolean := True);
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-- Analyze a use package clause and control (through the Chain parameter)
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-- whether to add N to the use clause chain for the name denoted within
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-- use clause N in case we are reanalyzing a use clause because of stack
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-- manipulation.
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procedure Analyze_Use_Type (N : Node_Id; Chain : Boolean := True);
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-- Similar to Analyze_Use_Package except the Chain parameter applies to the
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-- type within N's subtype mark Current_Use_Clause.
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procedure End_Scope;
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-- Called at end of scope. On exit from blocks and bodies (subprogram,
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-- package, task, and protected bodies), the name of the current scope
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-- must be removed from the scope stack, and the local entities must be
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-- removed from their homonym chains. On exit from record declarations,
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-- from package specifications, and from tasks and protected type
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-- specifications, more specialized procedures are invoked.
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procedure End_Use_Clauses (Clause : Node_Id);
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-- Invoked on scope exit, to undo the effect of local use clauses. Clause
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-- is the first use-clause of a scope being exited. This can be the current
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-- scope, or some enclosing scopes when building a clean environment to
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-- compile an instance body for inlining.
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procedure End_Use_Package (N : Node_Id);
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procedure End_Use_Type (N : Node_Id);
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-- Subsidiaries of End_Use_Clauses. Also called directly for use clauses
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-- appearing in context clauses.
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procedure Find_Direct_Name (N : Node_Id);
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-- Given a direct name (Identifier or Operator_Symbol), this routine scans
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-- the homonym chain for the name, searching for corresponding visible
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-- entities to find the referenced entity (or in the case of overloading,
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-- one candidate interpretation). On return, the Entity and Etype fields
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-- are set. In the non-overloaded case, these are the correct entries.
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-- In the overloaded case, the flag Is_Overloaded is set, Etype and Entity
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-- refer to an arbitrary element of the overloads set, and the appropriate
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-- entries have been added to the overloads table entry for the node. The
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-- overloading will be disambiguated during type resolution.
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--
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-- Note, when this is called during semantic analysis in the overloaded
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-- case, the entity set will be the most recently declared homonym. In
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-- particular, the caller may follow the homonym chain checking for all
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-- entries in the current scope, and that will give all homonyms that are
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-- declared before the point of call in the current scope. This is useful
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-- for example in the processing for pragma Inline.
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--
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-- Flag Errors_OK should be set when error diagnostics are desired. Flag
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-- Marker_OK should be set when a N_Variable_Reference_Marker needs to be
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-- generated for a SPARK object in order to detect elaboration issues. Flag
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-- Reference_OK should be set when N must generate a cross reference.
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procedure Find_Selected_Component (N : Node_Id);
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-- Resolve various cases of selected components, recognize expanded names
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procedure Find_Type (N : Node_Id);
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-- Perform name resolution, and verify that the name found is that of a
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-- type. On return the Entity and Etype fields of the node N are set
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-- appropriately. If it is an incomplete type whose full declaration has
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-- been seen, they are set to the entity in the full declaration. If it
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-- is an incomplete type associated with an interface visible through a
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-- limited-with clause, whose full declaration has been seen, they are
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-- set to the entity in the full declaration. Similarly, if the type is
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-- private, it has received a full declaration, and we are in the private
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-- part or body of the package, then the two fields are set to the entity
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-- of the full declaration as well. This procedure also has special
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-- processing for 'Class attribute references.
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function Has_Loop_In_Inner_Open_Scopes (S : Entity_Id) return Boolean;
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-- S is the entity of an open scope. This function determines if there is
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-- an inner scope of S which is a loop (i.e. it appears somewhere in the
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-- scope stack after S).
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function In_Open_Scopes (S : Entity_Id) return Boolean;
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-- S is the entity of a scope. This function determines if this scope is
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-- currently open (i.e. it appears somewhere in the scope stack).
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procedure Initialize;
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-- Initializes data structures used for visibility analysis. Must be
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-- called before analyzing each new main source program.
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procedure Install_Use_Clauses
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(Clause : Node_Id;
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Force_Installation : Boolean := False);
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-- Applies the use clauses appearing in a given declarative part,
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-- when the corresponding scope has been placed back on the scope
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-- stack after unstacking to compile a different context (subunit or
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-- parent of generic body). Force_Installation is used when called from
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-- Analyze_Subunit.Re_Install_Use_Clauses to insure that, after the
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-- analysis of the subunit, the parent's environment is again identical.
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procedure Mark_Use_Clauses (Id : Node_Or_Entity_Id);
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-- Mark a given entity or node Id's relevant use clauses as effective,
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-- including redundant ones and ones outside of the current scope.
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procedure Push_Scope (S : Entity_Id);
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-- Make new scope stack entry, pushing S, the entity for a scope onto the
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-- top of the scope table. The current setting of the scope suppress flags
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-- is saved for restoration on exit.
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procedure Pop_Scope;
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-- Remove top entry from scope stack, restoring the saved setting of the
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-- scope suppress flags.
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function Present_System_Aux (N : Node_Id := Empty) return Boolean;
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-- Return True if the auxiliary system file has been successfully loaded.
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-- Otherwise attempt to load it, using the name supplied by a previous
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-- Extend_System pragma, and report on the success of the load. If N is
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-- present, it is a selected component whose prefix is System, or else a
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-- with-clause on system. N is absent when the function is called to find
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-- the visibility of implicit operators.
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function Save_Scope_Stack
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(Handle_Use : Boolean := True) return Elist_Id;
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procedure Restore_Scope_Stack
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(List : Elist_Id;
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Handle_Use : Boolean := True);
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-- These two subprograms are called from Semantics, when a unit U1 is to
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-- be compiled in the course of the compilation of another unit U2. This
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-- happens whenever Rtsfind is called. U1, the unit retrieved by Rtsfind,
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-- must be compiled in its own context, and the current scope stack
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-- containing U2 and local scopes must be made unreachable. This is
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-- achieved using a call to Save_Scope_Stack. On return, the contents
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-- of the scope stack must be made accessible again with a call to
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-- Restore_Scope_Stack.
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--
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-- The flag Handle_Use indicates whether local use clauses must be removed
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-- or installed. In the case of inlining of instance bodies, the visibility
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-- handling is done fully in Inline_Instance_Body, and use clauses are
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-- handled there. Save_Scope_Stack returns the list of entities which have
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-- been temporarily removed from visibility; that list must be passed to
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-- Restore_Scope_Stack to restore their visibility.
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procedure Set_Use (L : List_Id);
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-- Find use clauses that are declarative items in a package declaration
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-- and set the potentially use-visible flags of imported entities before
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-- analyzing the corresponding package body.
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procedure Update_Use_Clause_Chain;
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-- Called at the end of a declarative region to detect unused use type
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-- clauses and maintain the Current_Use_Clause for type entities.
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procedure ws;
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-- Debugging routine for use in gdb: dump all entities on scope stack
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procedure we (S : Entity_Id);
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-- Debugging routine for use in gdb: dump all entities in given scope
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end Sem_Ch8;
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