Re: [PATCHv5] Handle TYPE_PACK_EXPANSION in cxx_incomplete_type_diagnostic

[Marek Polacek via Gcc-patches]

On Mon, Jun 22, 2020 at 06:55:01PM -0400, Nicholas Krause via Gcc-patches wrote:
> 
> 
> On 6/22/20 5:51 PM, Jason Merrill wrote:
> > On 6/22/20 4:01 PM, Nicholas Krause wrote:
> > > From: Nicholas Krause <xerofo...@gmail.com>
> > > 
> > > This fixs the PR95672 by adding the missing TYPE_PACK_EXPANSION case in
> > > cxx_incomplete_type_diagnostic in order to avoid ICES on diagnosing
> > > incomplete template pack expansion cases. In v2, add the missing required
> > > test case for all new patches. v3 Fixes both the test case to compile in
> > > C++11 mode and the message to print out only the type. v4 fixes the
> > > testcase
> > > to only target C++11. v5 fixes test case to run properly.
> > > 
> > > gcc/cp/ChangeLog:
> > > 
> > >     * typeck2.c (cxx_incomplete_type_diagnostic): Add missing
> > > TYPE_EXPANSION_PACK
> > >       check for diagnosticing incomplete types in
> > > cxx_incomplete_type_diagnostic.
> > > 
> > > gcc/testsuite/ChangeLog:
> > > 
> > >     * g++.dg/template/PR95672.C: New test.
> > > 
> > > Signed-off-by: Nicholas Krause <xerofo...@gmail.com>
> > > ---
> > >   gcc/cp/typeck2.c                        | 6 
> > > ++++++
> > >   gcc/testsuite/g++.dg/template/PR95672.C | 3 +++
> > >   2 files changed, 9 insertions(+)
> > >   create mode 100644 gcc/testsuite/g++.dg/template/PR95672.C
> > > 
> > > diff --git a/gcc/cp/typeck2.c b/gcc/cp/typeck2.c
> > > index 5fd3b82fa89..28b32fe0b5a 100644
> > > --- a/gcc/cp/typeck2.c
> > > +++ b/gcc/cp/typeck2.c
> > > @@ -552,6 +552,12 @@ cxx_incomplete_type_diagnostic (location_t loc,
> > > const_tree value,
> > >                  TYPE_NAME (type));
> > >         break;
> > > +    case TYPE_PACK_EXPANSION:
> > > +     emit_diagnostic (diag_kind, loc, 0,
> > > +             "invalid use of pack expansion %qT",
> > > +              type);
> > > +      break;
> > > +
> > >       case TYPENAME_TYPE:
> > >       case DECLTYPE_TYPE:
> > >         emit_diagnostic (diag_kind, loc, 0,
> > > diff --git a/gcc/testsuite/g++.dg/template/PR95672.C
> > > b/gcc/testsuite/g++.dg/template/PR95672.C
> > > new file mode 100644
> > > index 00000000000..fcc3da0a132
> > > --- /dev/null
> > > +++ b/gcc/testsuite/g++.dg/template/PR95672.C
> > > @@ -0,0 +1,3 @@
> > > +//c++ PR96572
> > > +// { dg-do compile { target c++11 } }
> > > +struct g_class : decltype  (auto) ... {  } ; // { dg-error "invalid
> > > use of pack expansion" }
> > 
> > FAIL: g++.dg/template/PR95672.C  -std=c++11  (test for errors, line 3)
> > FAIL: g++.dg/template/PR95672.C  -std=c++11 (test for excess errors)
> > 
> 
> It seems to pass for me with make check RUNTESTFLAGS=dg.exp=PR96752.ext

That doesn't test anything at all, because it's the wrong filename and the
wrong suffix.  Use

GXX_TESTSUITE_STDS=98,11,14,17,2a make check-c++ RUNTESTFLAGS=dg.exp=PR95672.C

Marek