Index: gcc/go/gofrontend/MERGE
===================================================================
--- gcc/go/gofrontend/MERGE	(revision 226452)
+++ gcc/go/gofrontend/MERGE	(working copy)
@@ -1,4 +1,4 @@
-19f0ec56bf278a9cbb100c6b24ec1a12c95ec41a
+bc4dda16f8686ab6e7335adfdfd2c6cc81cb2eb5
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.
Index: gcc/go/gofrontend/gogo.cc
===================================================================
--- gcc/go/gofrontend/gogo.cc	(revision 226448)
+++ gcc/go/gofrontend/gogo.cc	(working copy)
@@ -3258,6 +3258,17 @@ Gogo::check_types()
 {
   Check_types_traverse traverse(this);
   this->traverse(&traverse);
+
+  Bindings* bindings = this->current_bindings();
+  for (Bindings::const_declarations_iterator p = bindings->begin_declarations();
+       p != bindings->end_declarations();
+       ++p)
+    {
+      // Also check the types in a function declaration's signature.
+      Named_object* no = p->second;
+      if (no->is_function_declaration())
+        no->func_declaration_value()->check_types();
+    }
 }
 
 // Check the types in a single block.
@@ -5297,6 +5308,26 @@ Function_declaration::build_backend_desc
     }
 }
 
+// Check that the types used in this declaration's signature are defined.
+// Reports errors for any undefined type.
+
+void
+Function_declaration::check_types() const
+{
+  // Calling Type::base will give errors for any undefined types.
+  Function_type* fntype = this->type();
+  if (fntype->receiver() != NULL)
+    fntype->receiver()->type()->base();
+  if (fntype->parameters() != NULL)
+    {
+      const Typed_identifier_list* params = fntype->parameters();
+      for (Typed_identifier_list::const_iterator p = params->begin();
+           p != params->end();
+           ++p)
+        p->type()->base();
+    }
+}
+
 // Return the function's decl after it has been built.
 
 Bfunction*
Index: gcc/go/gofrontend/gogo.h
===================================================================
--- gcc/go/gofrontend/gogo.h	(revision 226009)
+++ gcc/go/gofrontend/gogo.h	(working copy)
@@ -1394,6 +1394,10 @@ class Function_declaration
   export_func(Export* exp, const std::string& name) const
   { Function::export_func_with_type(exp, name, this->fntype_); }
 
+  // Check that the types used in this declaration's signature are defined.
+  void
+  check_types() const;
+
  private:
   // The type of the function.
   Function_type* fntype_;