Add check for constrained auto type specifier in function declaration or function type declaration with trailing return type. Issue error if such usage is detected.
Test file renamed, and added a new test for type declaration. Successfully bootstrapped and regretested on x86_64-pc-linux-gnu: Added 6 passed and 4 unsupported tests. PR c++/100589 gcc/cp/ChangeLog: * decl.cc (grokdeclarator): Issue an error for a declarator with constrained auto type specifier and trailing return types. Include function names if available. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/concepts-pr100589.C: New test. Signed-off-by: Da Xie <xxie...@163.com> --- gcc/cp/decl.cc | 13 +++++++++++++ gcc/testsuite/g++.dg/cpp2a/concepts-pr100589.C | 9 +++++++++ 2 files changed, 22 insertions(+) create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-pr100589.C diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc index 9ca8c6c4481..337ee65752e 100644 --- a/gcc/cp/decl.cc +++ b/gcc/cp/decl.cc @@ -14037,6 +14037,19 @@ grokdeclarator (const cp_declarator *declarator, "invalid use of %<decltype(auto)%>"); return error_mark_node; } + else if (is_constrained_auto (type)) + { + if (funcdecl_p) + error_at (typespec_loc, + "%qs function with trailing return type " + "has constrained %<auto%> type specifier " + "rather than plain %<auto%>", + name); + else + error_at (typespec_loc, + "invalid use of constrained %<auto%> type"); + return error_mark_node; + } tree tmpl = CLASS_PLACEHOLDER_TEMPLATE (auto_node); if (!tmpl) if (tree late_auto = type_uses_auto (late_return_type)) diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-pr100589.C b/gcc/testsuite/g++.dg/cpp2a/concepts-pr100589.C new file mode 100644 index 00000000000..0c60d31f29b --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-pr100589.C @@ -0,0 +1,9 @@ +// PR c++/100589 +// { dg-do compile { target c++20 } } + +template<class T> +concept false_concept = false; + +false_concept auto f() -> int; // { dg-error "'f' .* trailing return type.* constrained 'auto'" } + +using type = false_concept auto() -> int; // { dg-error "invalid use of constrained 'auto' type"} -- 2.34.1