https://gcc.gnu.org/g:0c8300a9e0481130961415b4a5d7e647dec3ba66
commit r16-9627-g0c8300a9e0481130961415b4a5d7e647dec3ba66 Author: Patrick Palka <[email protected]> Date: Fri Aug 14 14:33:46 2026 -0400 c++: ICE w/ maybe_warn_nodiscard on non-dep call [PR123495, PR126860] Another latent issue uncovered by the NON_DEPENDENT_EXPR removal. cp_get_fndecl_from_callee, called from maybe_warn_nodiscard, tries to fold the templated callee via constant evaluation, but constant evaluation expects non-templated trees. So use fold_non_dependent_expr which instantiates templated trees beforehand. We could use f_n_d_init also but there should be no difference for a result that doesn't end up as NULL_TREE. PR c++/123495 PR c++/126860 gcc/cp/ChangeLog: * cvt.cc (cp_get_fndecl_from_callee): Use fold_non_dependent_expr instead of maybe_constant_init. gcc/testsuite/ChangeLog: * g++.dg/template/non-dependent36.C: New test. * g++.dg/template/non-dependent37.C: New test. Reviewed-by: Jason Merrill <[email protected]> (cherry picked from commit 0e74517b70d06105bd40c8caa6dc192b4af3ccff) Diff: --- gcc/cp/cvt.cc | 2 +- gcc/testsuite/g++.dg/template/non-dependent36.C | 4 ++++ gcc/testsuite/g++.dg/template/non-dependent37.C | 9 +++++++++ 3 files changed, 14 insertions(+), 1 deletion(-) diff --git a/gcc/cp/cvt.cc b/gcc/cp/cvt.cc index b1176317d996..44e7d8061859 100644 --- a/gcc/cp/cvt.cc +++ b/gcc/cp/cvt.cc @@ -1048,7 +1048,7 @@ cp_get_fndecl_from_callee (tree fn, bool fold /* = true */) if (type == NULL_TREE || !INDIRECT_TYPE_P (type)) return NULL_TREE; if (fold) - fn = maybe_constant_init (fn); + fn = fold_non_dependent_expr (fn); STRIP_NOPS (fn); if (TREE_CODE (fn) == ADDR_EXPR || TREE_CODE (fn) == FDESC_EXPR) diff --git a/gcc/testsuite/g++.dg/template/non-dependent36.C b/gcc/testsuite/g++.dg/template/non-dependent36.C new file mode 100644 index 000000000000..a4bf06974028 --- /dev/null +++ b/gcc/testsuite/g++.dg/template/non-dependent36.C @@ -0,0 +1,4 @@ +// PR c++/123495 + +template <int N> +void foo () { ((int (*) ()) 0) (); } diff --git a/gcc/testsuite/g++.dg/template/non-dependent37.C b/gcc/testsuite/g++.dg/template/non-dependent37.C new file mode 100644 index 000000000000..ad58cf6f10ce --- /dev/null +++ b/gcc/testsuite/g++.dg/template/non-dependent37.C @@ -0,0 +1,9 @@ +// PR c++/126860 + +struct A { + int (*foo)(); +}; + +template <typename T> struct S : public A { + void bar() { A::foo(); } +};
