## NON_FMT_PANICS

# Static NON_FMT_PANICS

Source

    static NON_FMT_PANICS: &Lint

Expand description

The `non_fmt_panics` lint detects `panic!(..)` invocations where the first argument is not a formatting string.

#### §Example

ⓘ

    panic!("{}");
    panic!(123);

{{produces}}

#### §Explanation

In Rust 2018 and earlier, `panic!(x)` directly uses `x` as the message. That means that `panic!("{}")` panics with the message `"{}"` instead of using it as a formatting string, and `panic!(123)` will panic with an `i32` as message.

Rust 2021 always interprets the first argument as format string.