Allow #[derive()] to generate unsafe methods

src/test/auxiliary/custom_derive_plugin.rs

@@ -54,6 +54,7 @@ fn expand(cx: &mut ExtCtxt,
                 args: vec![],
                 ret_ty: Literal(Path::new_local("isize")),
                 attributes: vec![],
+                is_unsafe: false,
                 combine_substructure: combine_substructure(box |cx, span, substr| {
                     let zero = cx.expr_isize(span, 0);
                     cs_fold(false,

src/test/auxiliary/custom_derive_plugin_attr.rs

@@ -56,6 +56,7 @@ fn expand(cx: &mut ExtCtxt,
                 args: vec![],
                 ret_ty: Literal(Path::new_local("isize")),
                 attributes: vec![],
+                is_unsafe: false,
                 combine_substructure: combine_substructure(Box::new(totalsum_substructure)),
             },
         ],