This patch fixes an error in the compiler whereby a spurious constraint
error is raised at runtime on type conversions between
access-to-discriminanted types when the object being converted is null.
Tested on x86_64-pc-linux-gnu, committed on trunk
gcc/ada/
* checks.adb (Make_Discriminant_Constraint_Check): Add check for
null when the type being converted is an access type.diff --git a/gcc/ada/checks.adb b/gcc/ada/checks.adb
--- a/gcc/ada/checks.adb
+++ b/gcc/ada/checks.adb
@@ -3658,6 +3658,20 @@ package body Checks is
Cond := Build_Discriminant_Checks (Expr, Expr_Type);
Set_Discriminant_Constraint (Expr_Type, Old_Constraints);
+ -- Conversion between access types requires that we check for null
+ -- before checking discriminants.
+
+ if Is_Access_Type (Etype (Expr)) then
+ Cond := Make_And_Then (Loc,
+ Left_Opnd =>
+ Make_Op_Ne (Loc,
+ Left_Opnd =>
+ Duplicate_Subexpr_No_Checks
+ (Expr, Name_Req => True),
+ Right_Opnd => Make_Null (Loc)),
+ Right_Opnd => Cond);
+ end if;
+
Insert_Action (N,
Make_Raise_Constraint_Error (Loc,
Condition => Cond,
