On 1/18/26 12:04 AM, Simon Martin wrote:
On Sat Jan 17, 2026 at 5:00 PM CET, Simon Martin wrote:
We currently ICE in decl_linkage for the following invalid input
because we access the TYPE_MAIN_VARIANT of error_mark_node
===
extern "C" {
template <a> class b;
struct {
typedef b:
===
This patch fixes this by returning no linkage for any TYPE_DECL with an
erroneous type.
PR c++/122391
gcc/cp/ChangeLog:
* tree.cc (decl_linkage): Return lk_none for TYPE_DECLs with
erroneous type.
gcc/testsuite/ChangeLog:
* g++.dg/parse/bitfield10.C: New test.
I forgot to say that I've succesfully bootstrapped and regtested this on
x86_64-pc-linux-gnu. OK for trunk?
OK.
---
gcc/cp/tree.cc | 11 +++++++----
gcc/testsuite/g++.dg/parse/bitfield10.C | 9 +++++++++
2 files changed, 16 insertions(+), 4 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/parse/bitfield10.C
diff --git a/gcc/cp/tree.cc b/gcc/cp/tree.cc
index a57eefaf11f3..030af4d219d1 100644
--- a/gcc/cp/tree.cc
+++ b/gcc/cp/tree.cc
@@ -6440,10 +6440,13 @@ decl_linkage (tree decl)
{
/* But this could be a typedef name for linkage purposes, in which
case we're interested in the linkage of the main decl. */
- if (decl == TYPE_NAME (TYPE_MAIN_VARIANT (TREE_TYPE (decl)))
- /* Likewise for the injected-class-name. */
- || DECL_SELF_REFERENCE_P (decl))
- decl = TYPE_MAIN_DECL (TREE_TYPE (decl));
+ tree type = TREE_TYPE (decl);
+ if (type == error_mark_node)
+ return lk_none;
+ else if (decl == TYPE_NAME (TYPE_MAIN_VARIANT (type))
+ /* Likewise for the injected-class-name. */
+ || DECL_SELF_REFERENCE_P (decl))
+ decl = TYPE_MAIN_DECL (type);
else
return lk_none;
}
diff --git a/gcc/testsuite/g++.dg/parse/bitfield10.C
b/gcc/testsuite/g++.dg/parse/bitfield10.C
new file mode 100644
index 000000000000..c5ab75932e7c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/parse/bitfield10.C
@@ -0,0 +1,9 @@
+/* PR c++/122391 */
+/* { dg-do "compile" } */
+
+extern "C" {
+ template <int> class b; /* { dg-error "with C linkage" } */
+ struct {
+ typedef b: /* { dg-error "at end of input" } */
+
+/* { dg-excess-errors "" } */
