New rule: No Match in Condition

[elbrujohalcon]

No Match in Condition

Brief Description

Pattern-matching should not be used in case statement conditions, like this:

case #{a := A} = do:something() of
    #{b := good} -> {a, really, nice, A};
    #{b := bad} -> {"not", a, good, A}
end

Should be on by default?

YES

Options

• None

Reasoning

While the code as written above is valid, it's much harder to understand (particularly for large statements) than the one below.

Refactoring Proposal

case do:something() of
    #{a := A, b := good} -> {a, really, nice, A};
    #{a := A, b := bad} -> {"not", a, good, A}
end

Origin (#281)

Inspired by the Refactor.MatchInCondition rule from Credo