Report useless patterns and pattern values that are not used.

config =
    [ NoUnused.Patterns.rule
    ]

This rule looks within let..in blocks and case branches to find any patterns that are unused. It will report any useless patterns as well as any pattern values that are not used.

Fail

Value something is not used:

case maybe of
    Just something ->
        True


    Nothing ->
        False

Success

case maybe of
    Just _ ->
        True


    Nothing ->
        False