From b3adcc60dcf3314f47f5409aecef40607f82b80b Mon Sep 17 00:00:00 2001 From: Patrick Palka Date: Wed, 26 Jul 2023 17:21:26 -0400 Subject: [PATCH] c++: passing partially inst tmpl as ttp [PR110566] Since the template arguments 'pargs' we pass to coerce_template_parms from coerce_template_template_parms are always a full set, we need to make sure we always pass the parameters of the most general template because if the template is partially instantiated then the levels won't match up. In the testcase below during said call to coerce_template_parms the parameters are {X, Y}, both level 1 rather than 2, and the arguments are {{int}, {N, M}}, which results in a crash during auto deduction for parameters' types. PR c++/110566 PR c++/108179 gcc/cp/ChangeLog: * pt.cc (coerce_template_template_parms): Simplify by using DECL_INNERMOST_TEMPLATE_PARMS and removing redundant asserts. Always pass the parameters of the most general template to coerce_template_parms. gcc/testsuite/ChangeLog: * g++.dg/template/ttp38.C: New test. --- gcc/cp/pt.cc | 12 +++++------- gcc/testsuite/g++.dg/template/ttp38.C | 12 ++++++++++++ 2 files changed, 17 insertions(+), 7 deletions(-) create mode 100644 gcc/testsuite/g++.dg/template/ttp38.C diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index 43818ba925fa..210d6222ef12 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -8073,12 +8073,10 @@ coerce_template_template_parms (tree parm_tmpl, tree parm, arg; int variadic_p = 0; - tree parm_parms = INNERMOST_TEMPLATE_PARMS (DECL_TEMPLATE_PARMS (parm_tmpl)); - tree arg_parms_full = DECL_TEMPLATE_PARMS (arg_tmpl); - tree arg_parms = INNERMOST_TEMPLATE_PARMS (arg_parms_full); - - gcc_assert (TREE_CODE (parm_parms) == TREE_VEC); - gcc_assert (TREE_CODE (arg_parms) == TREE_VEC); + tree parm_parms = DECL_INNERMOST_TEMPLATE_PARMS (parm_tmpl); + tree arg_parms = DECL_INNERMOST_TEMPLATE_PARMS (arg_tmpl); + tree gen_arg_tmpl = most_general_template (arg_tmpl); + tree gen_arg_parms = DECL_INNERMOST_TEMPLATE_PARMS (gen_arg_tmpl); nparms = TREE_VEC_LENGTH (parm_parms); nargs = TREE_VEC_LENGTH (arg_parms); @@ -8134,7 +8132,7 @@ coerce_template_template_parms (tree parm_tmpl, scope_args = TI_ARGS (tinfo); pargs = add_to_template_args (scope_args, pargs); - pargs = coerce_template_parms (arg_parms, pargs, NULL_TREE, tf_none); + pargs = coerce_template_parms (gen_arg_parms, pargs, NULL_TREE, tf_none); if (pargs != error_mark_node) { tree targs = make_tree_vec (nargs); diff --git a/gcc/testsuite/g++.dg/template/ttp38.C b/gcc/testsuite/g++.dg/template/ttp38.C new file mode 100644 index 000000000000..4a0c27f42aaa --- /dev/null +++ b/gcc/testsuite/g++.dg/template/ttp38.C @@ -0,0 +1,12 @@ +// PR c++/110566 +// { dg-do compile { target c++20 } } + +template class> +struct A; + +template +struct B { + template struct C; +}; + +using type = A::C>; -- 2.47.2