c++/10576: [3.3/3.4 regression] ICE in error recovery with a wrong template parameter default and a specialization

[giovannibajo@libero.it]

>Number:         10576
>Category:       c++
>Synopsis:       [3.3/3.4 regression] ICE in error recovery with a wrong template parameter default and a specialization
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          ice-on-illegal-code
>Submitter-Id:   net
>Arrival-Date:   Thu May 01 00:26:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:     Giovanni Bajo
>Release:        unknown-1.0
>Organization:
>Environment:
i686-pc-cygwin
>Description:
While playing with c++/10574, I found this regression:

----------------------------
template <typename>
struct A
{
    template <typename T = INVALID>
    struct C
    {
        typename T::x y;
    };

    template <>
    struct C<int> {};
};

A<int>::C<> a;
----------------------------
gccbug2.cpp:4: error: expected type-name
gccbug2.cpp:4: error: expected type-name
gccbug2.cpp:10: error: invalid explicit specialization
gccbug2.cpp:14: error: template argument 1 is invalid
gccbug2.cpp:14: internal compiler error: tree check: expected tree_vec, have error_mark in check_instantiated_args, at cp/pt.c:8401
Please submit a full bug report,


This is a regression wrt 2.95 where the compiler was not ICE-ing.
>How-To-Repeat:
Compile the above code
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: