c++/10793: [3.4 regression] ICE (treecheck) when partial-specializing with an invalid type and a base class, in xref_basetypes, at cp/decl.c:12834

[giovannibajo@libero.it]

>Number:         10793
>Category:       c++
>Synopsis:       [3.4 regression] ICE (treecheck) when partial-specializing with an invalid type and a base class, in xref_basetypes, at cp/decl.c:12834
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          ice-on-illegal-code
>Submitter-Id:   net
>Arrival-Date:   Wed May 14 23:26:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:     Giovanni Bajo
>Release:        3.4 CVS 20030503
>Organization:
>Environment:
i686-pc-cygwin
>Description:
This comes from Christian's analysys of c++/10722 (which is
a fallout from c++/10661):

----------------------------------------------
template <class P> struct spec_object_traits {};
template <class P, class Q> struct pair {};

template <typename T1>
struct spec_object_traits< pair<T1, INVALID> > :
   spec_object_traits<T1> { };
----------------------------------------------
gccbug6.cpp:4: error: `INVALID' has not been declared
gccbug6.cpp:4: error: template argument 2 is invalid
gccbug6.cpp:4: error: template argument 1 is invalid
gccbug6.cpp:5: internal compiler error: tree check: expected class 't', have 'x' (error_mark) in xref_basetypes, at cp/decl.c:12834
Please submit a full bug report,
>How-To-Repeat:
Compile the above snippet
>Fix:

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