Fix handling of fat pointer function arguments

The store for the "extra" data went to the wrong destination.

Author: dotdash

src/librustc_trans/trans/mir/mod.rs

@@ -169,7 +169,7 @@ fn arg_value_refs<'bcx, 'tcx>(bcx: Block<'bcx, 'tcx>,
                idx += 2;
                let lltemp = base::alloc_ty(bcx, arg_ty, &format!("arg{}", arg_index));
                build::Store(bcx, lldata, expr::get_dataptr(bcx, lltemp));
-               build::Store(bcx, llextra, expr::get_dataptr(bcx, lltemp));
+               build::Store(bcx, llextra, expr::get_meta(bcx, lltemp));
                lltemp
            } else {
                // otherwise, arg is passed by value, so make a