C++ PATCH for c++/89297 - ICE with OVERLOAD in template

[Jason Merrill]

On Wed, Feb 13, 2019 at 4:03 PM Marek Polacek <polacek@redhat.com> wrote:
> On Wed, Feb 13, 2019 at 11:59:05AM -0500, Marek Polacek wrote:
> > On Wed, Feb 13, 2019 at 11:44:42AM -0500, Jason Merrill wrote:
> > > On 2/13/19 12:13 AM, Marek Polacek wrote:
> > > > Here we ICE because we're in a template and the constructor contains an
> > > > OVERLOAD, so calling check_narrowing -> maybe_constant_value crashes.
> > > >
> > > > check_narrowing deliberately calls maybe_constant_value and not
> > > > fold_non_dependent_expr so as to avoid instantiating expressions twice.
> > > >
> > > > So let's use instantiate_non_dependent_expr_sfinae to deal with the OVERLOAD;
> > > > fold_non_dependent_expr always calls maybe_constant_value and we can avoid
> > > > that call.
> > > >
> > > > Bootstrapped/regtested on x86_64-linux, ok for trunk?
> > > >
> > > > 2019-02-12  Marek Polacek  <polacek@redhat.com>
> > > >
> > > >   PR c++/89297 - ICE with OVERLOAD in template.
> > > >   * semantics.c (finish_compound_literal): Call
> > > >   instantiate_non_dependent_expr_sfinae.
> > > >
> > > >   * g++.dg/cpp0x/initlist113.C: New test.
> > > >
> > > > diff --git gcc/cp/semantics.c gcc/cp/semantics.c
> > > > index 786f18ab0c8..e89a38d3cba 100644
> > > > --- gcc/cp/semantics.c
> > > > +++ gcc/cp/semantics.c
> > > > @@ -2826,9 +2826,13 @@ finish_compound_literal (tree type, tree compound_literal,
> > > >       return error_mark_node;
> > > >     compound_literal = reshape_init (type, compound_literal, complain);
> > > >     if (SCALAR_TYPE_P (type)
> > > > -      && !BRACE_ENCLOSED_INITIALIZER_P (compound_literal)
> > > > -      && !check_narrowing (type, compound_literal, complain))
> > > > -    return error_mark_node;
> > > > +      && !BRACE_ENCLOSED_INITIALIZER_P (compound_literal))
> > > > +    {
> > > > +      compound_literal
> > > > + = instantiate_non_dependent_expr_sfinae (compound_literal, complain);
> > > > +      if (!check_narrowing (type, compound_literal, complain))
> > > > + return error_mark_node;
> > > > +    }
> > >
> > > Since you change 'compound_literal', this seems to mean we will end up
> > > returning a constructor containing instantiated trees later instantiation
> > > isn't prepared to handle.
> >
> > Interesting, I don't recall seeing that, and it certainly regtested fine.  So
> > then we could instantiate the complit just for the check_narrowing purposes
> > and proceed as before?
>
> Now regtested/bootstrapped on x86_64-linux too.

OK.

Jason