[Ada] Raise expressions and unconstrained components

Message ID 20210616084355.GA94562@adacore.com
State New
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Series
  • [Ada] Raise expressions and unconstrained components
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Commit Message

Pierre-Marie de Rodat June 16, 2021, 8:43 a.m.
During the implementation of AI12-0172, we incorrectly allowed illegal
cases of unconstrained components.

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

gcc/ada/

	* sem_ch3.adb (Analyze_Component_Declaration): Do not special
	case raise expressions.

gcc/testsuite/

	* gnat.dg/limited4.adb: Disable illegal code.

Patch

diff --git a/gcc/ada/sem_ch3.adb b/gcc/ada/sem_ch3.adb
--- a/gcc/ada/sem_ch3.adb
+++ b/gcc/ada/sem_ch3.adb
@@ -2083,21 +2083,10 @@  package body Sem_Ch3 is
          end if;
       end if;
 
-      --  Avoid reporting spurious errors if the component is initialized with
-      --  a raise expression (which is legal in any expression context)
-
-      if Present (E)
-        and then
-          (Nkind (E) = N_Raise_Expression
-             or else (Nkind (E) = N_Qualified_Expression
-                        and then Nkind (Expression (E)) = N_Raise_Expression))
-      then
-         null;
-
       --  The parent type may be a private view with unknown discriminants,
       --  and thus unconstrained. Regular components must be constrained.
 
-      elsif not Is_Definite_Subtype (T)
+      if not Is_Definite_Subtype (T)
         and then Chars (Id) /= Name_uParent
       then
          if Is_Class_Wide_Type (T) then


diff --git a/gcc/testsuite/gnat.dg/limited4.adb b/gcc/testsuite/gnat.dg/limited4.adb
--- a/gcc/testsuite/gnat.dg/limited4.adb
+++ b/gcc/testsuite/gnat.dg/limited4.adb
@@ -22,11 +22,12 @@  procedure Limited4 is
     Obj2 : Lim_Tagged'Class := Lim_Tagged'Class'(raise TBD_Error);
 
     --  b) initialization expression of a CW component_declaration
-
-    type Rec is record
-       Comp01 : Lim_Tagged'Class := (raise TBD_Error);
-       Comp02 : Lim_Tagged'Class := Lim_Tagged'Class'((raise TBD_Error));
-    end record;
+    --  ... is illegal: cannot have unconstrained components.
+    --
+    --  type Rec is record
+    --     Comp01 : Lim_Tagged'Class := (raise TBD_Error);
+    --     Comp02 : Lim_Tagged'Class := Lim_Tagged'Class'((raise TBD_Error));
+    --  end record;
 
     --  c) the expression of a record_component_association
 
@@ -55,4 +56,4 @@  procedure Limited4 is
 begin
     Check := Do_Test1 (raise TBD_Error);
     Check := Do_Test2;
-end;
\ No newline at end of file
+end;