[Ada] Spurious error on dynamic predicate in a generic context

[Pierre-Marie de Rodat]

This patch fixes a spurious error on the conformance checking between
the expression for an aspect analyzed at the freeze point of the type,
and the analysis of a copy of the expression performed at the end of the
enclosing list of declarationss. In a generic context the first may not
have been analyzed yet and this must be done before the conformance
check.

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

2019-07-03  Ed Schonberg  <schonb...@adacore.com>

gcc/ada/

        * sem_ch13.adb (Analyze_Attribute_Definition_Clause): No error
        message on attribute applied to a renaming when the renamed
        object is an aggregate (from code reading).
        (Check_Aspect_At_End_Of_Declarations): In a generic context
        where freeze nodes are not generated, the original expression
        for an aspect may need to be analyzed to precent spurious
        conformance errors when compared with the expression that is
        anakyzed at the end of the current declarative list.

gcc/testsuite/

        * gnat.dg/predicate5.adb, gnat.dg/predicate5.ads: New testcase.
--- gcc/ada/sem_ch13.adb
+++ gcc/ada/sem_ch13.adb
@@ -4934,8 +4934,12 @@ package body Sem_Ch13 is
         and then Present (Renamed_Object (Ent))
       then
          --  Case of renamed object from source, this is an error
+         --  unless the pbject is an aggregate and the renaming is
+         --  created for an object declaration.
 
-         if Comes_From_Source (Renamed_Object (Ent)) then
+         if Comes_From_Source (Renamed_Object (Ent))
+           and then Nkind (Renamed_Object (Ent)) /= N_Aggregate
+         then
             Get_Name_String (Chars (N));
             Error_Msg_Strlen := Name_Len;
             Error_Msg_String (1 .. Name_Len) := Name_Buffer (1 .. Name_Len);
@@ -9336,6 +9340,16 @@ package body Sem_Ch13 is
       --  All other cases
 
       else
+
+         --  In a generic context freeze nodes are not always generated,
+         --  so analyze the expression now.
+
+         if not Analyzed (Freeze_Expr)
+           and then Inside_A_Generic
+         then
+            Preanalyze (Freeze_Expr);
+         end if;
+
          --  Indicate that the expression comes from an aspect specification,
          --  which is used in subsequent analysis even if expansion is off.
 

--- /dev/null
new file mode 100644
+++ gcc/testsuite/gnat.dg/predicate5.adb
@@ -0,0 +1,5 @@
+--  { dg-do compile }
+
+package body Predicate5 is
+   procedure Foo is null;
+end Predicate5;

--- /dev/null
new file mode 100644
+++ gcc/testsuite/gnat.dg/predicate5.ads
@@ -0,0 +1,17 @@
+generic
+   type Value_Type is private;
+package Predicate5 is
+   type MT (Has : Boolean := False) is record
+      case Has is
+         when False =>
+            null;
+         when True =>
+            MX : Value_Type;
+      end case;
+   end record;
+   function Foo (M : MT) return Boolean is (not M.Has);
+   subtype LT is MT with Dynamic_Predicate => not LT.Has;
+   function Bar (M : MT) return Boolean is (Foo (M));
+
+   procedure Foo;
+end;