[Ada] Unnesting problems with expansion of Loop_Entry attribute

2020-06-03  Gary Dismukes  <dismukes@adacore.com>

gcc/ada/

	* exp_attr.adb (Expand_Loop_Entry_Attribute): Revise loop that
	resets the scopes of entities associated with Loop_Id to the
	scope of the new function, so the resetting is not restricted to
	itypes, but excludes loop parameters and the function entity
	itself. However, this fix is believed to be incomplete and a ???
	comment is added to indicate that.

1 files changed, 25 insertions, 11 deletions

diff --git a/gcc/ada/exp_attr.adb b/gcc/ada/exp_attr.adb
index 6c59ae0..939183c 100644
--- a/gcc/ada/exp_attr.adb
+++ b/gcc/ada/exp_attr.adb
@@ -1434,22 +1434,36 @@ package body Exp_Attr is
                Insert_Action (Loop_Stmt, Func_Decl);
                Pop_Scope;
 
-               --  The analysis of the condition may have generated itypes
-               --  that are now used within the function: Adjust their
-               --  scopes accordingly so that their use appears in their
-               --  scope of definition.
+               --  The analysis of the condition may have generated entities
+               --  (such as itypes) that are now used within the function.
+               --  Adjust their scopes accordingly so that their use appears
+               --  in their scope of definition.
 
                declare
-                  Ityp : Entity_Id;
+                  Ent : Entity_Id;
 
                begin
-                  Ityp := First_Entity (Loop_Id);
-
-                  while Present (Ityp) loop
-                     if Is_Itype (Ityp) then
-                        Set_Scope (Ityp, Func_Id);
+                  Ent := First_Entity (Loop_Id);
+
+                  while Present (Ent) loop
+                     --  Various entities that now occur within the function
+                     --  need to have their scope reset, but not all entities
+                     --  associated with Loop_Id are now inside the function.
+                     --  The function entity itself and loop parameters can
+                     --  be outside the function, and there may be others.
+                     --  It's not clear how the determination of what entity
+                     --  scopes need to be adjusted can be made accurately.
+                     --  Perhaps it will be necessary to traverse the function
+                     --  body to find the exact entities whose scopes need to
+                     --  be reset to the function's Entity_Id. ???
+
+                     if Ekind (Ent) /= E_Loop_Parameter
+                       and then Ent /= Func_Id
+                     then
+                        Set_Scope (Ent, Func_Id);
                      end if;
-                     Next_Entity (Ityp);
+
+                     Next_Entity (Ent);
                   end loop;
                end;