This patch to the Go frontend gives a more useful error message for an
invalid call to unsafe.Offsetof on a method value (method values look
like field references, which are valid for unsafe.offsetof).
Bootstrapped and ran Go testsuite on x86_64-unknown-linux-gnu.
Committed to mainline. Will commit to 4.8 branch when it reopens.
Ian
diff -r 07ab2f26915d go/expressions.cc
--- a/go/expressions.cc Fri Oct 11 10:44:51 2013 -0700
+++ b/go/expressions.cc Fri Oct 11 11:05:45 2013 -0700
@@ -7253,6 +7253,15 @@
if (this->code_ == BUILTIN_OFFSETOF)
{
Expression* arg = this->one_arg();
+
+ if (arg->bound_method_expression() != NULL
+ || arg->interface_field_reference_expression() != NULL)
+ {
+ this->report_error(_("invalid use of method value as argument "
+ "of Offsetof"));
+ return this;
+ }
+
Field_reference_expression* farg = arg->field_reference_expression();
while (farg != NULL)
{
@@ -7262,7 +7271,8 @@
// it must not be reached through pointer indirections.
if (farg->expr()->deref() != farg->expr())
{
- this->report_error(_("argument of Offsetof implies indirection of an embedded field"));
+ this->report_error(_("argument of Offsetof implies "
+ "indirection of an embedded field"));
return this;
}
// Go up until we reach the original base.
@@ -7672,6 +7682,8 @@
bool
Builtin_call_expression::do_is_constant() const
{
+ if (this->is_error_expression())
+ return true;
switch (this->code_)
{
case BUILTIN_LEN:
