Static rustc_lint_defs::builtin::MISSING_FRAGMENT_SPECIFIER

pub static MISSING_FRAGMENT_SPECIFIER: &'static Lint

The missing_fragment_specifier lint is issued when an unused pattern in a macro_rules! macro definition has a meta-variable (e.g. $e) that is not followed by a fragment specifier (e.g. :expr).

This warning can always be fixed by removing the unused pattern in the macro_rules! macro definition.

Example

macro_rules! foo {
   () => {};
   ($name) => { };
}

fn main() {
   foo!();
}

{{produces}}

Explanation

To fix this, remove the unused pattern from the macro_rules! macro definition:

macro_rules! foo {
    () => {};
}
fn main() {
    foo!();
}