+ if let ExprKind::MethodCall(path, _, args, _) = expr.kind;
+ if path.ident.name == sym!(to_string);
+ if let Some(expr_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
+ if is_diag_trait_item(cx, expr_def_id, sym::ToString);
+ if path_to_local_id(&args[0], self_hir_id);