https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104091
Bug ID: 104091
Summary: -std=c++20 causing meaningless error message "'auto'
not allowed in alias declaration" which should be
"missing template arguments after ..."
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: nickhuang99 at hotmail dot com
Target Milestone: ---
considering following snippet of code:
template<typename T, template<typename...>typename Template>
struct Specialization{};
template<template<typename...>typename Template, typename...Args>
struct Specialization<Template<Args...>, Template>{
using type=Template;
};
Using -std=c++20 gives meaningless error message of "'auto' not allowed in
alias declaration". While -std=c++17 or before all give correct error message:
"missing template arguments after 'Template<...auto...>'". And -std=c++14 is
even better with "invalid use of template-name 'Template' without an argument
list".
See https://godbolt.org/z/Wb9nKzcPT
