https://gcc.gnu.org/g:1c555ba67a34ced2460a065eac05ae2e2693ca4d
commit r16-6248-g1c555ba67a34ced2460a065eac05ae2e2693ca4d Author: Jakub Jelinek <[email protected]> Date: Thu Dec 18 16:41:10 2025 +0100 c++: Fix up recent cp_parser_template_id regression [PR123186] On Fri, Dec 12, 2025 at 09:39:18AM -0500, Patrick Palka wrote: > + TREE_TYPE (templ) > + = build_typename_type (TYPE_CONTEXT (TREE_TYPE (templ)), > + TYPE_NAME (TREE_TYPE (templ)), > + fullname, > + get_typename_type_tag (TREE_TYPE (templ))); > template_id = templ; > } > else This change causes ICE e.g. on the following testcase. The problem is that build_typename_type expects IDENTIFIER_NODE as the second argument, e.g. it uses it as tree d = build_decl (input_location, TYPE_DECL, name, t); argument. But TYPE_NAME doesn't have to be an IDENTIFIER_NODE, it can be a TYPE_DECL too and when we build a TYPE_DECL with TYPE_DECL as DECL_NAME, it breaks all kinds of assumptions everywhere in the FE as well as middle-end. Fixed by using TYPE_IDENTIFIER instead. 2025-12-18 Jakub Jelinek <[email protected]> PR c++/123186 * parser.cc (cp_parser_template_id): Use TYPE_IDENTIFIER instead of TYPE_NAME in second build_typename_type argument. * g++.dg/template/crash133.C: New test. Diff: --- gcc/cp/parser.cc | 2 +- gcc/testsuite/g++.dg/template/crash133.C | 6 ++++++ 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc index 18df3b1014e9..521c05549f1e 100644 --- a/gcc/cp/parser.cc +++ b/gcc/cp/parser.cc @@ -20435,7 +20435,7 @@ cp_parser_template_id (cp_parser *parser, fullname, arguments); TREE_TYPE (templ) = build_typename_type (TYPE_CONTEXT (TREE_TYPE (templ)), - TYPE_NAME (TREE_TYPE (templ)), + TYPE_IDENTIFIER (TREE_TYPE (templ)), fullname, get_typename_tag (TREE_TYPE (templ))); template_id = templ; diff --git a/gcc/testsuite/g++.dg/template/crash133.C b/gcc/testsuite/g++.dg/template/crash133.C new file mode 100644 index 000000000000..9a1a6b136c64 --- /dev/null +++ b/gcc/testsuite/g++.dg/template/crash133.C @@ -0,0 +1,6 @@ +// PR c++/123186 + +template <class T> +struct A : T { + typename A <T>::template B <42> C; +};
