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Core Lint error with LambdaCase

    • Closed Issue created by Richard Eisenberg @rae

    When I say

    {-# LANGUAGE LambdaCase, TypeFamilies #-}

type family F a where
  F a = Bool -> a

foo = (\case True -> 5
             False -> 6) :: F Int

    -dcore-lint tells me

    *** Core Lint errors : in result of Desugar (after optimization) ***
/Users/rae/temp/Bug.hs:6:1: Warning:
    [RHS of foo :: Bool -> Int]
    From-type of Cast differs from type of enclosed expression
...

    The problem is a missing mkTcSymCo in the relevant bit of tcExpr.

    Will fix in ongoing work.

    Trac metadata
    Trac field Value
    Version 7.10.1
    Type Bug
    TypeOfFailure OtherFailure
    Priority normal
    Resolution Unresolved
    Component Compiler (Type checker)
    Test case
    Differential revisions
    BlockedBy
    Related
    Blocking
    CC
    Operating system
    Architecture
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