Go patch committed: Don't assign to embedded builtin types in composite literals

[Ian Lance Taylor]

This patch by Chris Manghane fixes the Go frontend to not permit
assigning to embedded builtin types in a composite literal for an
imported struct.  The builtin types are not exported names, but they
are represented as simple names rather than as hidden names (with a
leading dot).  This is http://golang.org/issue/6832 .  Bootstrapped
and ran Go testsuite on x86_64-unknown-linux-gnu.  Committed to
mainline.

Ian

diff -r e027abc3dc5b go/expressions.cc
--- a/go/expressions.cc Tue Jan 06 16:14:01 2015 -0800
+++ b/go/expressions.cc Wed Jan 07 07:34:24 2015 -0800
@@ -12937,7 +12937,8 @@
               pf != st->fields()->end();
               ++pf)
            {
-             if (Gogo::is_hidden_name(pf->field_name()))
+             if (Gogo::is_hidden_name(pf->field_name())
+                 || pf->is_embedded_builtin(gogo))
                error_at(this->location(),
                         "assignment of unexported field %qs in %qs literal",
                         Gogo::message_name(pf->field_name()).c_str(),
@@ -13114,7 +13115,8 @@
 
       if (type->named_type() != NULL
          && type->named_type()->named_object()->package() != NULL
-         && Gogo::is_hidden_name(sf->field_name()))
+         && (Gogo::is_hidden_name(sf->field_name())
+             || sf->is_embedded_builtin(gogo)))
        error_at(name_expr->location(),
                 "assignment of unexported field %qs in %qs literal",
                 Gogo::message_name(sf->field_name()).c_str(),