par-load.adb (Load): If a child unit is loaded through a limited_with clause...

2005-07-07  Ed Schonberg  <schonberg@adacore.com>
	    Javier Miranda  <miranda@adacore.com>

	* par-load.adb (Load): If a child unit is loaded through a limited_with
	clause, each parent must be loaded as a limited unit as well.

	* sem_ch10.adb (Previous_Withed_Unit): Better name for
	Check_Withed_Unit. Return true if there is a previous with_clause for
	this unit, whether limited or not.
	(Expand_Limited_With_Clause): Do not generate a limited_with_clause on
	the current unit.
	(Is_Visible_Through_Renamings): New local subprogram of install_limited
	_withed_unit that checks if some package installed through normal with
	clauses has a renaming declaration of package whose limited-view is
	ready to be installed. This enforces the check of the rule 10.1.2 (21/2)
	of the current Draft document for Ada 2005.
	(Analyze_Context): Complete the list of compilation units that
	are allowed to contain limited-with clauses. It also contains
	checks that were previously done by Install_Limited_Context_Clauses.
	This makes the code more clear and easy to maintain.
	(Expand_Limited_With_Clause) It is now a local subprogram of
	Install_Limited_Context_Clauses, and contains the code that adds
	the implicit limited-with clauses for parents of child units.
	This functionality was prevously done by Analyze_Context.

	* sem_ch4.adb (Analyze_Selected_Component): Check wrong use of
	incomplete type.

	* sem_ch7.adb (Analyze_Package_Declaration): Check if the package has
	been erroneously named in a limited-with clause of its own context.
	In this case the error has been previously notified by Analyze_Context.

From-SVN: r101697

gcc/ada/par-load.adb

@@ -301,6 +301,8 @@ begin
       end if;
 
    --  If current unit is a child unit spec, load its parent
+   --  If the child unit is loaded through a limited with, the parent
+   --  must be as well.
 
    elsif Nkind (Unit (Curunit)) = N_Package_Declaration
      or else Nkind (Unit (Curunit)) =  N_Subprogram_Declaration
@@ -323,7 +325,8 @@ begin
              (Load_Name  => Spec_Name,
               Required   => True,
               Subunit    => False,
-              Error_Node => Curunit);
+              Error_Node => Curunit,
+              From_Limited_With => From_Limited_With);
 
          if Unum /= No_Unit then
             Set_Parent_Spec (Unit (Curunit), Cunit (Unum));

gcc/ada/sem_ch4.adb

@@ -2679,6 +2679,25 @@ package body Sem_Ch4 is
 
                Resolve (Name);
 
+               --  Ada 2005 (AI-50217): Check wrong use of incomplete type.
+               --  Example:
+
+               --    limited with Pkg;
+               --    package Pkg is
+               --       type Acc_Inc is access Pkg.T;
+               --       X : Acc_Inc;
+               --       N : Natural := X.all.Comp; -- ERROR
+               --    end Pkg;
+
+               if Nkind (Name) = N_Explicit_Dereference
+                 and then From_With_Type (Etype (Prefix (Name)))
+                 and then not Is_Potentially_Use_Visible (Etype (Name))
+               then
+                  Error_Msg_NE
+                    ("premature usage of incomplete}", Prefix (Name),
+                     Etype (Prefix (Name)));
+               end if;
+
                --  We never need an actual subtype for the case of a selection
                --  for a indexed component of a non-packed array, since in
                --  this case gigi generates all the checks and can find the

gcc/ada/sem_ch7.adb

@@ -623,6 +623,17 @@ package body Sem_Ch7 is
       PF : Boolean;
 
    begin
+      --  Ada 2005 (AI-217): Check if the package has been erroneously named
+      --  in a limited-with clause of its own context. In this case the error
+      --  has been previously notified by Analyze_Context.
+
+      --     limited with Pkg; -- ERROR
+      --     package Pkg is ...
+
+      if From_With_Type (Id) then
+         return;
+      end if;
+
       Generate_Definition (Id);
       Enter_Name (Id);
       Set_Ekind (Id, E_Package);