compiler: Disallow call of *T method using **T variable.

Fixes https://code.google.com/p/go/issues/detail?id=8583.

From-SVN: r214560

gcc/go/gofrontend/types.cc

@@ -9453,10 +9453,11 @@ Type::bind_field_or_method(Gogo* gogo, const Type* type, Expression* expr,
 	  else
 	    go_unreachable();
 	  go_assert(m != NULL);
-	  if (dereferenced && m->is_value_method())
+	  if (dereferenced)
 	    {
 	      error_at(location,
-		       "calling value method requires explicit dereference");
+		       "calling method %qs requires explicit dereference",
+		       Gogo::message_name(name).c_str());
 	      return Expression::make_error(location);
 	    }
 	  if (!m->is_value_method() && expr->type()->points_to() == NULL)

gcc/testsuite/go.test/test/fixedbugs/bug371.go

@@ -8,10 +8,10 @@
 
 package main
 
-type T struct {}
+type T struct{}
 
 func (t *T) pm() {}
-func (t T) m() {}
+func (t T) m()   {}
 
 func main() {
 	p := &T{}
@@ -20,5 +20,5 @@ func main() {
 
 	q := &p
 	q.m()  // ERROR "requires explicit dereference"
-	q.pm()
+	q.pm() // ERROR "requires explicit dereference"
 }