On 3/5/26 7:03 PM, Marek Polacek wrote:
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
-- >8 --
I noticed that we don't issue an error in the test in [dcl.attr.annotation]
for /4: "Substituting into an annotation is not in the immediate context":
template<class T>
[[=T::type()]] void f(T t);
void f(int);
void g() {
f(0); // OK
f('0'); // error, substituting into the annotation results in an
invalid expression
}
PR c++/124381
gcc/cp/ChangeLog:
* pt.cc (tsubst_attribute): Always complain for annotations.
gcc/testsuite/ChangeLog:
* g++.dg/reflect/annotations13.C: New test.
---
gcc/cp/pt.cc | 5 +++++
gcc/testsuite/g++.dg/reflect/annotations13.C | 15 +++++++++++++++
2 files changed, 20 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/reflect/annotations13.C
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index ddf492b3435..36b9fbeb0b6 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -12347,6 +12347,11 @@ tsubst_attribute (tree t, tree *decl_p, tree args,
{
gcc_assert (ATTR_IS_DEPENDENT (t));
+ /* [dcl.attr.annotation]/4: Substituting into an annotation is not in
+ the immediate context. */
+ if (annotation_p (t))
+ complain = tf_warning_or_error;
+
tree val = TREE_VALUE (t);
if (val == NULL_TREE)
/* Nothing to do. */;
diff --git a/gcc/testsuite/g++.dg/reflect/annotations13.C
b/gcc/testsuite/g++.dg/reflect/annotations13.C
new file mode 100644
index 00000000000..19306956e78
--- /dev/null
+++ b/gcc/testsuite/g++.dg/reflect/annotations13.C
@@ -0,0 +1,15 @@
+// PR c++/124381
+// { dg-do compile { target c++26 } }
+// { dg-additional-options "-freflection" }
+// Test from [dcl.attr.annotation].
+
+template<class T>
+[[=T::type()]] void f(T t); // { dg-error "not a member" }
+
+void f(int);
+
+void g() {
+ f(0); // OK
+ f('0'); // error, substituting into the annotation results in an
invalid expression
What if there's another template that's a better match? I'm concerned
that this only works because f(int) is a perfect match for the first
call so we never even form the candidate from the template.
We don't want this error until we've chosen the annotated template as
the best candidate.
+// { dg-message "required from here" "" { target *-*-* } .-1 }
+}
base-commit: 0970bb8565616f61c6b7a7dd0edbc829b0064703
