error[E0618]: expected function, found `{integer}` --> $DIR/issue-26237.rs:20:18 | LL | $not_a_function($some_argument) | ------------------------------- call expression requires function ... LL | let mut value_a = 0; | ----------- `{integer}` defined here LL | let mut value_b = 0; LL | macro_panic!(value_a, value_b); | ^^^^^^^ error: aborting due to previous error For more information about this error, try `rustc --explain E0618`.