On 9/30/26 9:34 PM, Marek Polacek wrote:
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/branches?
OK.
-- >8 --
Here we crash in decl_namespace_context because function types
(or pointer-to-data-member types) like void() have no TYPE_MAIN_DECL:
decl = CP_DECL_CONTEXT (TYPE_MAIN_DECL (decl));
We got there from the constrain_class_visibility TYPE_FIELDS walk
which emits the -Wsubobject-linkage warning. And this test has:
namespace { struct P { }; }
struct S { void (*f) (P *); };
I'm using OVERLOAD_TYPE_P, inspired by min_vis_r.
PR c++/127672
gcc/cp/ChangeLog:
* decl2.cc (constrain_class_visibility): Check OVERLOAD_TYPE_P
before calling decl_anon_ns_mem_p.
gcc/testsuite/ChangeLog:
* g++.dg/warn/Wsubobject-linkage-6.C: New test.
---
gcc/cp/decl2.cc | 1 +
gcc/testsuite/g++.dg/warn/Wsubobject-linkage-6.C | 10 ++++++++++
2 files changed, 11 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/warn/Wsubobject-linkage-6.C
diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc
index 7fe567f98db..563fae5db0d 100644
--- a/gcc/cp/decl2.cc
+++ b/gcc/cp/decl2.cc
@@ -3598,6 +3598,7 @@ constrain_class_visibility (tree type)
type, t, nlt);
}
else if (cxx_dialect > cxx98
+ && OVERLOAD_TYPE_P (ftype)
&& !decl_anon_ns_mem_p (ftype))
warning (OPT_Wsubobject_linkage, "\
%qT has a field %q#D whose type has internal linkage",
diff --git a/gcc/testsuite/g++.dg/warn/Wsubobject-linkage-6.C
b/gcc/testsuite/g++.dg/warn/Wsubobject-linkage-6.C
new file mode 100644
index 00000000000..ea77f14386f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wsubobject-linkage-6.C
@@ -0,0 +1,10 @@
+// PR c++/127672
+// { dg-do compile { target c++11 } }
+
+namespace { struct P { }; }
+
+#line 7 "foo.C"
+struct S { void (*f) (P *); }; // { dg-warning "uses the anonymous
namespace" }
+struct S2 { void (P::*m) (); }; // { dg-warning "uses the anonymous
namespace" }
+struct S3 { P (*g) (); }; // { dg-warning "uses the anonymous
namespace" }
+struct S4 { int P::*d; }; // { dg-warning "uses the anonymous
namespace" }
base-commit: f7094fe5ff882f0c206d51ebe93f33f0193ce636
