fix: resolve redundant clause warnings in Elixir 1.20#30
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polvalente merged 1 commit intoJul 20, 2026
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Remove dead-code clauses in divide/2 and atan2/2 already matched by earlier clauses returning the same value, and fix a clause-ordering bug in pow/2 where the :neg_infinity zero-base case was unreachable because the non-finite catch-all matched first. Move it before the catch-all, symmetric with the :infinity case.
josevalim
approved these changes
Jul 18, 2026
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Elixir 1.20's gradual set-based type analysis flags three redundant clauses. Two were dead code already matched by earlier clauses; one was a clause-ordering bug that surfaced via the warning.
divide/2— Removeddef divide(n, b) when is_number(n) and b in [:infinity, :neg_infinity]. The earlierdivide(a, :infinity)anddivide(a, :neg_infinity)clauses already match and return0.pow/2— Moveddef pow(%Complex{re: re, im: im}, :neg_infinity) when re == 0 and im == 0before thepow(%Complex{}, z) when is_non_finite_number(z)catch-all. Previously the catch-all matched first, so this clause was unreachable dead code. It now producesnew(:infinity, 0)(0^-∞ = ∞), symmetric with the:infinityzero-base case (0^∞ = 0).atan2/2— Removeddef atan2(:nan, :nan). The earlieratan2(:nan, a) when is_number(a) or is_non_finite_number(a)already matches(:nan, :nan)and returns:nan.The corresponding test assertion for
pow(Complex.new(0, 0), :neg_infinity)is updated fromnew(:nan, :nan)tonew(:infinity, 0)to reflect the now-correct runtime behavior (the old assertion encoded the buggy catch-all result).mix compile --warnings-as-errorsis clean;mix testpasses 70/70 with no new failures.