The problem turned out to be that lookup_anon_field was not able to find a FIELD_DECL so we passed NULL member to finish_class_member_access_expr and that SEGVs on that. The reason is that "const struct C" object does not have any fields; for that, we need to look at the main variant. So fixed by doing just that, lookup_anon_field is then able to find the decl and we don't ICE anymore.
Bootstrapped/regtested on x86_64-linux, ok for trunk? Strictly speaking, it's not a regression, but the fix doesn't look terribly risky either. 2015-03-20 Marek Polacek <pola...@redhat.com> PR c++/65072 * typeck.c (lookup_anon_field): Make sure we're dealing with the main variant. * g++.dg/cpp0x/pr65072.C: New test. diff --git gcc/cp/typeck.c gcc/cp/typeck.c index 4c128b7..e9d4cae 100644 --- gcc/cp/typeck.c +++ gcc/cp/typeck.c @@ -2213,6 +2213,8 @@ lookup_anon_field (tree t, tree type) { tree field; + t = TYPE_MAIN_VARIANT (t); + for (field = TYPE_FIELDS (t); field; field = DECL_CHAIN (field)) { if (TREE_STATIC (field)) diff --git gcc/testsuite/g++.dg/cpp0x/pr65072.C gcc/testsuite/g++.dg/cpp0x/pr65072.C index e69de29..b8fa888 100644 --- gcc/testsuite/g++.dg/cpp0x/pr65072.C +++ gcc/testsuite/g++.dg/cpp0x/pr65072.C @@ -0,0 +1,14 @@ +// PR c++/65075 +// { dg-do compile { target c++11 } } +// { dg-options "-Wno-pedantic" } + +template <typename> class C +{ + struct + { + int i; + }; + auto operator*(const C m) -> decltype (m.i); +}; +void fn1 (const C<float>); +C<float> a; Marek