[Bug c++/52841] [4.7/4.8 Regression] error: type 'Solvable' is not a base type for type 'Resolvable'

["fabien at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52841

--- Comment #8 from fabien at gcc dot gnu.org 2012-04-17 21:08:13 UTC ---
It is related to alias declarations. It seems that we do not recover properly
from a failure in cp_parser_alias_declaration, in the block introduced by this
check: "if (!(flags & CP_PARSER_FLAGS_NO_USER_DEFINED_TYPES))", around here:

#0  cp_parser_simple_type_specifier (parser=0x7ffff571b738,
decl_specs=0x7fffffffdd00, flags=1) at ../../gcc/gcc/cp/parser.c:13651
#1  0x00000000006be5e0 in cp_parser_type_specifier (parser=0x7ffff571b738,
flags=1, decl_specs=0x7fffffffdd00, is_declaration=0 '\000',
declares_class_or_enum=0x0, is_cv_qualifier=0x7fffffffdcde "") at
../../gcc/gcc/cp/parser.c:13434
#2  0x00000000006c5c96 in cp_parser_type_specifier_seq (parser=0x7ffff571b738,
is_declaration=0 '\000', is_trailing_return=0 '\000',
type_specifier_seq=0x7fffffffdd00) at ../../gcc/gcc/cp/parser.c:16887
#3  0x00000000006c5a63 in cp_parser_type_id_1 (parser=0x7ffff571b738,
is_template_arg=0 '\000', is_trailing_return=0 '\000') at
../../gcc/gcc/cp/parser.c:16771
#4  0x00000000006c5b57 in cp_parser_type_id (parser=0x7ffff571b738) at
../../gcc/gcc/cp/parser.c:16810
#5  0x00000000006c1987 in cp_parser_alias_declaration (parser=0x7ffff571b738)
at ../../gcc/gcc/cp/parser.c:15101

I can't find what goes wrong there. The good news is that it seems to work if
we return earlier in cp_parser_alias_declaration -- which I think is better --,
like in the attached patch.

Perhaps Dodji (or Jason) can take a closer look ?