We currently check satisfaction in the context of the constrained declaration (which may be wrong, see PR104111). When checking C<int> for S<int>, we currently substitute into the lambda in the context of S<T> (rather than S<int>, which seems wrong if the above isn't wrong), so the new closure type thinks its context is S<T>, which confuses debug output. For the moment, let's work around all of this by overriding the context of the closure.
Tested x86_64-pc-linux-gnu, applying to trunk. PR c++/105652 gcc/cp/ChangeLog: * pt.cc (tsubst_lambda_expr): Don't let a namespace-scope lambda instantiate into a class-scope lambda. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/concepts-lambda20.C: New test. --- gcc/cp/pt.cc | 17 ++++++++++++----- gcc/testsuite/g++.dg/cpp2a/concepts-lambda20.C | 17 +++++++++++++++++ 2 files changed, 29 insertions(+), 5 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-lambda20.C diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index 24bbe2f4060..f1f080531a6 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -19740,11 +19740,18 @@ tsubst_lambda_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl) return error_mark_node; if (LAMBDA_EXPR_EXTRA_SCOPE (t) == NULL_TREE) - /* A lambda in a default argument outside a class gets no - LAMBDA_EXPR_EXTRA_SCOPE, as specified by the ABI. But - tsubst_default_argument calls start_lambda_scope, so we need to - specifically ignore it here, and use the global scope. */ - record_null_lambda_scope (r); + { + /* A lambda in a default argument outside a class gets no + LAMBDA_EXPR_EXTRA_SCOPE, as specified by the ABI. But + tsubst_default_argument calls start_lambda_scope, so we need to + specifically ignore it here, and use the global scope. */ + record_null_lambda_scope (r); + + /* If we're pushed into another scope (PR105652), fix it. */ + if (TYPE_NAMESPACE_SCOPE_P (TREE_TYPE (t))) + TYPE_CONTEXT (type) = DECL_CONTEXT (TYPE_NAME (type)) + = TYPE_CONTEXT (TREE_TYPE (t)); + } else record_lambda_scope (r); diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-lambda20.C b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda20.C new file mode 100644 index 00000000000..40e5973176e --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda20.C @@ -0,0 +1,17 @@ +// PR c++/105652 +// { dg-do compile { target c++20 } } +// { dg-additional-options -g } + +template<int> +struct I {}; + +template<class T> +concept C = []<int N>(I<N>) { return true; } (I<0>{}); + +template<class T> +struct S { }; + +template<C T> +struct S<T> { constexpr static bool value = true; }; + +static_assert(S<int>::value); base-commit: d9176e643f385c3ef3b8c28cbc0468776fd8a14f -- 2.27.0