Fix: narrow "Parenthesize unary negation" to surprising precedence (fixes #1636)#1685
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Fix: narrow "Parenthesize unary negation" to surprising precedence (fixes #1636)#1685mgajda wants to merge 1 commit into
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…ixes ndmitchell#1636) The hint was introduced in ndmitchell#1484 for cases where unary negation combines with higher-fixity operators in non-obvious ways: -1 ^ 2 -- parses as -(1^2) = -1, not (-1)^2 = 1 -5 `mod` 3 -- parses as -(5 `mod` 3), which returns -2 It also fired on fixity-7 symbolic operators (`*`, `+`, `/`), where the precedence matches the conventional mathematical reading and the extra parens are just noise — as flagged in ndmitchell#1636: addUTCTime (-365.25 * nominalDay * fromIntegral y) Narrow the rule to only fire on operators that are actually surprising: - alphanumeric functions infixed with backticks (fixity 9) - exponentiation: `^`, `^^`, `**` (fixity 8) This keeps the canonical ndmitchell#1484 cases firing while silencing the ndmitchell#1636 noise.
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Summary
Fixes #1636. The "Parenthesize unary negation" hint (introduced by #1484)
was firing on conventional arithmetic operators where the precedence
matches the reader's mental model, producing noise like:
Narrow the rule to the operators where precedence around unary
-isgenuinely surprising:
-5 `mod` 3parses as-(5 \mod` 3) = -2` — the classic Suggest explicit brackets to mitigate counter-intuitive prefix negation precedence #1484 case.^/^^/**(fixity 8):-1 ^ 2 = -1, not1— also canonical in Suggest explicit brackets to mitigate counter-intuitive prefix negation precedence #1484.
Conventional arithmetic (
+,-,*,/, fixity 6–7) no longertriggers the hint.
Test plan
hlint --testpasses (969 tests)-1 ^ 2still triggers (canonical Suggest explicit brackets to mitigate counter-intuitive prefix negation precedence #1484 case preserved)-365.25 * nominalDay * fromIntegral yno longer triggers (Incorrect "Parenthesize unary negation" suggestion #1636)