https://gcc.gnu.org/g:cb828691fe692f9df002a2e3757a1aec68857e85
commit r15-7127-gcb828691fe692f9df002a2e3757a1aec68857e85
Author: Marek Polacek <pola...@redhat.com>
Date: Tue Jan 21 14:48:46 2025 -0500
c++: further tweak to cxx_eval_outermost_constant_expr [PR118396]
This patch adds an error in a !allow_non_constant case when the
initializer/object types don't match.
PR c++/118396
gcc/cp/ChangeLog:
* constexpr.cc (cxx_eval_outermost_constant_expr): Add an error call
when !allow_non_constant.
Reviewed-by: Jason Merrill <ja...@redhat.com>
Diff:
---
gcc/cp/constexpr.cc | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc
index 9f950ffed749..41ff78bbf2b9 100644
--- a/gcc/cp/constexpr.cc
+++ b/gcc/cp/constexpr.cc
@@ -9092,11 +9092,19 @@ cxx_eval_outermost_constant_expr (tree t, bool
allow_non_constant,
return r;
else if (non_constant_p && TREE_CONSTANT (r))
r = mark_non_constant (r);
- else if (non_constant_p
- /* Check we are not trying to return the wrong type. */
- || !same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (r)))
+ else if (non_constant_p)
return t;
+ /* Check we are not trying to return the wrong type. */
+ if (!same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (r)))
+ {
+ /* If so, this is not a constant expression. */
+ if (!allow_non_constant)
+ error ("%qE is not a constant expression because it initializes "
+ "a %qT rather than %qT", t, TREE_TYPE (t), type);
+ return t;
+ }
+
if (should_unshare)
r = unshare_expr (r);
