re PR c++/37256 (extern template / explicit instantiation broken in 4.4.0-pre)

        PR c++/37256
        * pt.c (instantiate_decl): Don't require a definition of
        a template that is explicitly instantiated 'extern'.

From-SVN: r142014

gcc/cp/ChangeLog

+2008-11-19  Jason Merrill  <jason@redhat.com>
+
+	PR c++/37256
+	* pt.c (instantiate_decl): Don't require a definition of
+	a template that is explicitly instantiated 'extern'.
+
 2008-11-18  Jason Merrill  <jason@redhat.com>
 	    Jakub Jelinek  <jakub@redhat.com>
 	

gcc/cp/pt.c

@@ -15226,7 +15226,8 @@ instantiate_decl (tree d, int defer_ok,
       input_location = saved_loc;
 
       if (at_eof && !pattern_defined
-	  && DECL_EXPLICIT_INSTANTIATION (d))
+	  && DECL_EXPLICIT_INSTANTIATION (d)
+	  && DECL_NOT_REALLY_EXTERN (d))
 	/* [temp.explicit]
 
 	   The definition of a non-exported function template, a

gcc/testsuite/ChangeLog

+2008-11-19  Jason Merrill  <jason@redhat.com>
+
+	PR c++/37256
+	* g++.dg/cpp0x/extern_template-3.C: New test.
+
 2008-11-19  Maxim Kuvyrkov  <maxim@codesourcery.com>
 
 	* gcc.target/m68k/xgot-1.c (dg-options): Add -O2.

gcc/testsuite/g++.dg/cpp0x/extern_template-3.C

+// PR c++/37256
+// { dg-options "-O" }
+
+template <typename T_>
+struct B
+{
+  T_ f();
+};
+
+extern template class B<int>;
+
+void f()
+{
+  B<int> t;
+  t.f();
+}