[C++ Patch] PR 50391

[Paolo Carlini]

Hi,

here I'm just avoiding calling build_exception_variant when specs is an 
error_mark_node.

Tested x86_64-linux. Ok for mainline?

Thanks,
Paolo.

/////////////////////
/cp
2011-09-14  Paolo Carlini  <paolo.carl...@oracle.com>

        PR c++/50391
        * pt.c (regenerate_decl_from_template): Don't pass an error_mark_node
        to build_exception_variant.

/testsuite
2011-09-14  Paolo Carlini  <paolo.carl...@oracle.com>

        PR c++/50391
        * g++.dg/cpp0x/noexcept15.C: New.
Index: testsuite/g++.dg/cpp0x/noexcept15.C
===================================================================
--- testsuite/g++.dg/cpp0x/noexcept15.C (revision 0)
+++ testsuite/g++.dg/cpp0x/noexcept15.C (revision 0)
@@ -0,0 +1,34 @@
+// PR c++/50391
+// { dg-options -std=c++0x }
+
+#include <type_traits>
+
+template<class Tp>
+  struct single
+  {
+    Tp elem;  // { dg-error "incomplete type" }
+
+    constexpr single(const Tp& e)
+    : elem(e) { }   // { dg-error "invalid field" }
+
+    single(single&& s) // { dg-error "not a member" }
+    noexcept(std::is_nothrow_move_constructible<Tp>::value) 
+    : elem(s.elem) { } // { dg-error "invalid field|no member" }
+  };
+
+template<class Tp>
+  constexpr single<typename std::decay<Tp>::type>
+  make_single(Tp&& x)
+  {
+    return single<typename std::decay<Tp>::type>(x);
+  }
+
+class Blob;  // { dg-error "forward declaration" }
+
+void
+foo(Blob *b)
+{
+  make_single(*b);
+}
+
+// { dg-prune-output "include" }
Index: cp/pt.c
===================================================================
--- cp/pt.c     (revision 178845)
+++ cp/pt.c     (working copy)
@@ -17729,7 +17729,7 @@ regenerate_decl_from_template (tree decl, tree tmp
       specs = tsubst_exception_specification (TREE_TYPE (code_pattern),
                                              args, tf_error, NULL_TREE,
                                              /*defer_ok*/false);
-      if (specs)
+      if (specs && specs != error_mark_node)
        TREE_TYPE (decl) = build_exception_variant (TREE_TYPE (decl),
                                                    specs);