[Ada] Fix scopes for local variables in task/protected bodies

[Pierre-Marie de Rodat <derodat@adacore.com>]

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No impact on compilation with GCC.

Tested on x86_64-pc-linux-gnu, committed on trunk

2019-07-09  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* sem_util.adb (Scope_Within_Or_Same): Handle properly task
	bodies and protected bodies, so that local variables within have
	their proper scopes after these constructs have been rewritten
	during expansion. This patch resembles but is not identical to
	the code in Scope_Within.

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--- gcc/ada/sem_util.adb
+++ gcc/ada/sem_util.adb
@@ -24268,13 +24268,32 @@ package body Sem_Util is
      (Inner : Entity_Id;
       Outer : Entity_Id) return Boolean
    is
-      Curr : Entity_Id;
-
+      Curr : Entity_Id := Inner;
    begin
-      Curr := Inner;
+      --  Similar to the above, but check for scope identity first.
+
       while Present (Curr) and then Curr /= Standard_Standard loop
          if Curr = Outer then
             return True;
+
+         elsif Ekind (Curr) = E_Task_Type
+           and then Outer = Task_Body_Procedure (Curr)
+         then
+            return True;
+
+         elsif Is_Subprogram (Curr)
+           and then Outer = Protected_Body_Subprogram (Curr)
+         then
+            return True;
+
+         elsif Is_Private_Type (Curr)
+           and then Present (Full_View (Curr))
+         then
+            if Full_View (Curr) = Outer then
+               return True;
+            else
+               return Scope_Within (Full_View (Curr), Outer);
+            end if;
          end if;
 
          Curr := Scope (Curr);