c++: DMI in template with virtual base [PR106890]

When parsing a default member init we just build a CONVERT_EXPR for
converting to a virtual base, and then expand that into the more complex
form when we actually use the DMI in a constructor.  But that wasn't working
for the template case where we are considering the conversion at the point
that the constructor needs the DMI instantiation, so it seemed like we were
in a constructor already.  And then when the other constructor tries to
reuse the instantiation, it sees uses of the first constructor's parameters,
and dies.  So ensure that we get the CONVERT_EXPR in this case, too.

	PR c++/106890

gcc/cp/ChangeLog:

	* init.cc (maybe_instantiate_nsdmi_init): Don't leave
	current_function_decl set to a constructor.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/nsdmi-template25.C: New test.

diff --git a/gcc/cp/init.cc b/gcc/cp/init.cc
index 90302372340ec981a9cbd05b846e893bae7f0089..c5a55dae56393831d2a1a2bd3433361e95110ef7 100644 (file)
--- a/gcc/cp/init.cc
+++ b/gcc/cp/init.cc
@@ -613,6 +613,18 @@ maybe_instantiate_nsdmi_init (tree member, tsubst_flags_t complain)
              pushed = true;
            }
 
+         /* If we didn't push_to_top_level, still step out of constructor
+            scope so build_base_path doesn't try to use its __in_chrg.  */
+         tree cfd = current_function_decl;
+         auto cbl = current_binding_level;
+         if (at_function_scope_p ())
+           {
+             current_function_decl
+               = decl_function_context (current_function_decl);
+             while (current_binding_level->kind != sk_class)
+               current_binding_level = current_binding_level->level_chain;
+           }
+
          inject_this_parameter (ctx, TYPE_UNQUALIFIED);
 
          start_lambda_scope (member);
@@ -629,6 +641,8 @@ maybe_instantiate_nsdmi_init (tree member, tsubst_flags_t complain)
          if (init != error_mark_node)
            hash_map_safe_put<hm_ggc> (nsdmi_inst, member, init);
 
+         current_function_decl = cfd;
+         current_binding_level = cbl;
          if (pushed)
            {
              pop_deferring_access_checks ();

diff --git a/gcc/testsuite/g++.dg/cpp0x/nsdmi-template25.C b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template25.C
new file mode 100644 (file)
index 0000000..368e745
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template25.C
@@ -0,0 +1,18 @@
+// PR c++/106890
+// { dg-do compile { target c++11 } }
+
+struct A
+{
+  int p;
+};
+
+template<typename T>
+struct B : virtual public A
+{
+  B() { }
+  B(int) { }
+
+  int k = this->p;
+};
+
+template struct B<int>;