On Wed, 7 Dec 2022, Patrick Palka wrote: > In extract_autos_r, we need to reset TYPE_CANONICAL for the template > type parameter after adjusting its index, otherwise we end up with a > comptypes ICE for the below testcase. Note that such in-place type > adjustment isn't generallly safe to do since the type could be the > TYPE_CANONICAL of another (unadjusted) type, but in this case the > canonical auto (of some level and 0 index) is the first auto (of that > level) that's created, and so any auto that we do end up adjusting can't > be the canonical one. > > Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for > trunk?
Ping. FWIW this blocks the modules + std::source_location patch[1] because the make_auto() call it adds to cxx_init_decl_processing would otherwise cause us to ICE on the existing test g++.dg/concepts/auto1.C. [1]: https://gcc.gnu.org/pipermail/gcc-patches/2022-December/608127.html > > PR c++/101886 > > gcc/cp/ChangeLog: > > * pt.cc (extract_autos_r): Reset TYPE_CANONICAL after > adjusting the template type parameter's index. Simplify > by using TEMPLATE_TYPE_IDX. Add some sanity checks. > > gcc/testsuite/ChangeLog: > > * g++.dg/concepts/auto5.C: New test. > --- > gcc/cp/pt.cc | 12 +++++++++--- > gcc/testsuite/g++.dg/concepts/auto5.C | 9 +++++++++ > 2 files changed, 18 insertions(+), 3 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/concepts/auto5.C > > diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc > index 24ed718ffbb..d05a49b1c11 100644 > --- a/gcc/cp/pt.cc > +++ b/gcc/cp/pt.cc > @@ -29164,18 +29164,24 @@ extract_autos_r (tree t, void *data) > { > /* All the autos were built with index 0; fix that up now. */ > tree *p = hash.find_slot (t, INSERT); > - unsigned idx; > + int idx; > if (*p) > /* If this is a repeated constrained-type-specifier, use the index we > chose before. */ > - idx = TEMPLATE_PARM_IDX (TEMPLATE_TYPE_PARM_INDEX (*p)); > + idx = TEMPLATE_TYPE_IDX (*p); > else > { > /* Otherwise this is new, so use the current count. */ > *p = t; > idx = hash.elements () - 1; > } > - TEMPLATE_PARM_IDX (TEMPLATE_TYPE_PARM_INDEX (t)) = idx; > + if (idx != TEMPLATE_TYPE_IDX (t)) > + { > + gcc_checking_assert (TEMPLATE_TYPE_IDX (t) == 0); > + gcc_checking_assert (TYPE_CANONICAL (t) != t); > + TEMPLATE_TYPE_IDX (t) = idx; > + TYPE_CANONICAL (t) = canonical_type_parameter (t); > + } > } > > /* Always keep walking. */ > diff --git a/gcc/testsuite/g++.dg/concepts/auto5.C > b/gcc/testsuite/g++.dg/concepts/auto5.C > new file mode 100644 > index 00000000000..f1d653efd87 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/concepts/auto5.C > @@ -0,0 +1,9 @@ > +// PR c++/101886 > +// { dg-do compile { target c++17_only } } > +// { dg-options "-fconcepts-ts" } > + > +template<typename...> struct A { }; > + > +A<int, int> a; > +A<auto, auto> b1 = a; > +A<auto, auto> b2 = a; > -- > 2.39.0.rc2 > >
