From c1c62aec6751678e958ab5c61b2d903a09d7efd9 Mon Sep 17 00:00:00 2001 From: Patrick Palka Date: Thu, 8 Oct 2020 00:05:41 -0400 Subject: [PATCH] c++: ICE in dependent_type_p with constrained auto [PR97052] This patch fixes an "unguarded" call to coerce_template_parms in build_standard_check: processing_template_decl could be zero if we get here during processing of the first 'auto' parameter of an abbreviated function template, or if we're processing the type constraint of a non-templated variable. In the testcase below, this leads to an ICE when coerce_template_parms instantiates C's dependent default template argument. gcc/cp/ChangeLog: PR c++/97052 * constraint.cc (build_type_constraint): Temporarily increment processing_template_decl before calling build_concept_check. * pt.c (make_constrained_placeholder_type): Likewise. gcc/testsuite/ChangeLog: PR c++/97052 * g++.dg/cpp2a/concepts-defarg2.C: New test. --- gcc/cp/constraint.cc | 2 ++ gcc/cp/pt.c | 2 ++ gcc/testsuite/g++.dg/cpp2a/concepts-defarg2.C | 13 +++++++++++++ 3 files changed, 17 insertions(+) create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-defarg2.C diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc index d49957a..050b55c 100644 --- a/gcc/cp/constraint.cc +++ b/gcc/cp/constraint.cc @@ -1427,7 +1427,9 @@ tree build_type_constraint (tree decl, tree args, tsubst_flags_t complain) { tree wildcard = build_nt (WILDCARD_DECL); + ++processing_template_decl; tree check = build_concept_check (decl, wildcard, args, complain); + --processing_template_decl; if (check == error_mark_node) return error_mark_node; return unpack_concept_check (check); diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index fc4b9bb..9a83810 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -27928,7 +27928,9 @@ make_constrained_placeholder_type (tree type, tree con, tree args) tree expr = tmpl; if (TREE_CODE (con) == FUNCTION_DECL) expr = ovl_make (tmpl); + ++processing_template_decl; expr = build_concept_check (expr, type, args, tf_warning_or_error); + --processing_template_decl; PLACEHOLDER_TYPE_CONSTRAINTS (type) = expr; diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-defarg2.C b/gcc/testsuite/g++.dg/cpp2a/concepts-defarg2.C new file mode 100644 index 0000000..a63ca4e --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-defarg2.C @@ -0,0 +1,13 @@ +// PR c++/97052 +// { dg-do compile { target c++20 } } + +template +concept C = true; + +constexpr bool f(C auto) { + return true; +} + +static_assert(f(0)); + +C auto x = 0; -- 2.7.4