https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111493
Bug ID: 111493 Summary: [concepts] multidimensional subscript operator inside requires is broken Product: gcc Version: 14.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: elrodc at gmail dot com Target Milestone: --- Two example programs: > #include <concepts> > constexpr auto foo(const auto &A, int i, int j) > requires(requires(decltype(A) a, int ii) { a[ii, ii]; }) { > return A[i, j]; > } > constexpr auto foo(const auto &A, int i, int j) { > return A + i + j; > } > static_assert(foo(2,3,4) == 9); > #include <concepts> > template <typename T, typename S> > concept CartesianIndexable = requires(T t, int i) { > { t[i, i] } -> std::convertible_to<S>; > }; > static_assert(!CartesianIndexable<double,int>); These result in errors of the form error: invalid types 'const int[int]' for array subscript Here is godbolt for reference: https://godbolt.org/z/WE66nY8zG The invalid subscript should result in the `requires` failing, not an error.