Ticket #2146 (closed bug: fixed)
Decomposition rule for equalities is too weak in case of higher-kinded type families
|Reported by:||chak||Owned by:||chak|
|Component:||Compiler (Type checker)||Version:||6.9|
|Type of failure:||Difficulty:||Unknown|
|Test Case:||Blocked By:|
foo :: (F Int a ~ F Int [a]) => a -> [a] foo = undefined
Occurs check: cannot construct the infinite type: a = [a]
foo :: (F Int a ~ F Bool [a]) => a -> [a] foo = undefined
doesn't - although both should lead to the same error.
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