On Wed, Jan 23, 2019 at 12:57 PM Marek Polacek <pola...@redhat.com> wrote:
>
> On Wed, Jan 23, 2019 at 09:00:36AM -0500, Jason Merrill wrote:
> > I was talking about digest_init, not reshape_init. digest_init calls
> > convert_for_initialization.
>
> /facepalm
>
> So yes, digest_init calls convert_for_initialization which will end up
> calling perform_implicit_conversion_flags which could call convert_like_real
> where the narrowing warnings are given, but it doesn't, we go to this case:
>
> else if (processing_template_decl && conv->kind != ck_identity)
> {
> /* In a template, we are only concerned about determining the
> type of non-dependent expressions, so we do not have to
> perform the actual conversion. But for initializers, we
> need to be able to perform it at instantiation
> (or instantiate_non_dependent_expr) time. */
> expr = build1 (IMPLICIT_CONV_EXPR, type, expr);
>
> finish_decltype_type throws away the expression because it's not dependent,
> and
> only uses its type. So narrowing remains undetected. Not sure if I should
> mess
> with perform_implicit_conversion_flags.
Let's try that; this is a situation where the comment is incorrect.
Perhaps just call check_narrowing here if appropriate, rather than go
through the whole conversion machinery.
Jason
