[COMMITTED 17/30] ada: Crash in prefix notation with access to class-wide object

[Marc Poulhiès]

From: Javier Miranda <mira...@adacore.com>

The compiler crashes analyzing a prefix notation call when its
prefix is an access to a class-wide object, an actual parameter
is missing, and the sources are compiled with language extensions
(-gnatX) and full errors (-gnatf).

gcc/ada/ChangeLog:

        * sem_ch4.adb (Try_Object_Operation): if no candidate interpretation
        matches the context, redo the same analysis with Report_Error True
        to report the error.

Tested on x86_64-pc-linux-gnu, committed on master.

---
 gcc/ada/sem_ch4.adb | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/gcc/ada/sem_ch4.adb b/gcc/ada/sem_ch4.adb
index 18b3a4fc22f..94e43429814 100644
--- a/gcc/ada/sem_ch4.adb
+++ b/gcc/ada/sem_ch4.adb
@@ -10498,6 +10498,11 @@ package body Sem_Ch4 is
       Set_Etype (Subprog, Any_Type);
       Set_Parent (New_Call_Node, Parent (Node_To_Replace));
 
+      --  Perform the analysis searching for a candidate with Report_Error
+      --  set to False (see above); if no candidate interpretation matches
+      --  the context, this analysis will be redone with Report_Error set
+      --  to True to provide additional information.
+
       if not Is_Overloaded (Obj) then
          Try_One_Prefix_Interpretation (Obj_Type);
 
@@ -10537,18 +10542,22 @@ package body Sem_Ch4 is
 
          if All_Errors_Mode then
             Report_Error := True;
-            if Try_Primitive_Operation
-                 (Call_Node       => New_Call_Node,
-                  Node_To_Replace => Node_To_Replace)
 
-              or else
-                Try_Class_Wide_Operation
-                  (Call_Node       => New_Call_Node,
-                   Node_To_Replace => Node_To_Replace)
-            then
-               null;
-            end if;
+            if not Is_Overloaded (Obj) then
+               Try_One_Prefix_Interpretation (Obj_Type);
 
+            else
+               declare
+                  I  : Interp_Index;
+                  It : Interp;
+               begin
+                  Get_First_Interp (Obj, I, It);
+                  while Present (It.Nam) loop
+                     Try_One_Prefix_Interpretation (It.Typ);
+                     Get_Next_Interp (I, It);
+                  end loop;
+               end;
+            end if;
          else
             Analyze_One_Call
               (N          => New_Call_Node,
-- 
2.43.0