struct A {};
template <class T>
struct B : public T
{
B ();
};
B<A*
foo ()
{
return new B<A>();
}
template <class T>
B<T>::B ()
{
}
template <>
B<A>::B ()
{
}
ICEs at i inline_forbidden_p:
1448 FR_EACH_BB_FN (bb, DECL_STRUCT_FUNCTIN (fndecl))
as fndecl (B ctor) doesn't have cfg set (DECL_STRUCT_FUNCTIN (fndecl)->cfg ==
NULL).

Comment #2 from bangerth at dealii dot org 2006-06-16 22:51
Confirmed.

Comment #3 from bangerth at dealii dot org 2006-06-16 22:55
The code is invalid, however: explicit specializations must be declared
before they are first used. In the snippet, B<A>::B is used in foo()
before the specialization is declared. The ICE consequently also goes
away if a declaration (not definition) of the specialization precedes foo().

That all doesn't make it any more forgivable that we ICE on this code,
however.

W.

Comment #4 from pinskia at gcc dot gnu dot org 2006-06-24 23:53
Bug 28159 has been marked as a duplicate of this bug.

Comment #5 from reichelt at gcc dot gnu dot org 2006-07-12 16:39
Here's a testcase that crashes even at since GCC 4.1.0:

template<intstruct A
{
A() {}
};

A<0a;

template<A<0>::A() {}

As Wolfgang already mentioned: explicit specializations must be declared
before they are first used.
However, no diagnostic is required. (Which indicates that such situations
are hard to detect reliably.)

Comment #6 from hubicka at gcc dot gnu dot org 2006-07-21 20:36
cgraph_analyze_function is reentrant for non-unit-at-a-time support. However
with unit-at-a-time, the analysis happens only after unit has been finalized
and at that time frontend is not supposed to come up with new functions
anymore. It would be a lot better to make C++ frontend to handle this case
early (probably diagnose the invalid code?), but I don't quite understand this
area of compiler, so if someone C++ aware would tell me it is dificult, we can
do it as workaround.

Honza

Comment #7 from janis at gcc dot gnu dot org 2006-08-14 16:16
Regression hunts on powerpc-linux showed that the original testcase with
and the testcase in comment #5 with both start getting segfaults with the
following patch:

r99840 | hubicka | 2005-05-17 16:56:32 +0000 (Tue, 17 May 2005)

Comment #8 from mmitchel at gcc dot gnu dot org 2006-08-26 16:53
We do have code to notice use-before-specialization errors. For example:

template <typename Tvoid f();
void g() {
f<int>();
}
template <void f<int>() {}

results in an error.

However, the code to initialize static variables is not generated until
end-of-file, so we do not realize that we are in this situation. (See
expand_static_init for the point at which we defer initialization.)

Comment #9 from mmitchel at gcc dot gnu dot org 2006-08-27 17:45
Subject: Bug 28058

Author: mmitchel
Date: Sun Aug 27 17:45:25 2006
New Revision: 116491

URL:
Log:
PR c++/28058
* pt.c (register_specialization): Return error_mark_node for

* decl2.c (mark_used): Mark the main function used when one of its
clones is used.

PR c++/28058
* gdg/template/spec31.C: New test.

Added:

Modified:
trunk/gcc/cp/ChangeLog
trunk/gcc/cp/decl2.c
trunk/gcc/cp/pt.c
trunk/gcc/testsuite/ChangeLog

Comment #10 from mmitchel at gcc dot gnu dot org 2006-08-27 18:00
Subject: Bug 28058

Author: mmitchel
Date: Sun Aug 27 17:59:55 2006
New Revision: 116492

URL:
Log:
PR c++/28058
* pt.c (register_specialization): Return error_mark_node for

* decl2.c (mark_used): Mark the main function used when one of its
clones is used.

PR c++/28058
* gdg/template/spec31.C: New test.
* gold-deja/gpt/spec9.C: Adjust error markers.

Added:

Modified:

Comment #11 from mmitchel at gcc dot gnu dot org 2006-08-27 18:00
Fixed in 4.1.2.