Credence.Pattern.NoCondTwoClauses (credence v0.7.1)

Detects cond with exactly two clauses where the second guard is redundant — either literal true or the logical complement of the first guard. Both patterns are just an if/else in disguise.

Bad

cond do
  low > high -> false
  true ->
    mid = div(low + high, 2)
    search(mid, target)
end

cond do
  x <= target -> go_right
  x > target -> found
end

Good

if low > high do
  false
else
  mid = div(low + high, 2)
  search(mid, target)
end

if x <= target do
  go_right
else
  found
end

Auto-fix

Rewrites as if/else using the first clause's guard as the condition. The condition is never modified.

For the complement case the rewrite is only applied when the guard's operands are plain variables or literals. A cond's second guard is re-evaluated when the first is false, whereas the if/else evaluates the condition only once; restricting to side-effect-free, deterministic operands keeps the fix behaviour-preserving on every input.