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Redefining (~) yields a baffling error message

    • Closed Issue created by Ryan Scott @RyanGlScott

    Running this code:

    {-# LANGUAGE TypeOperators #-}
module Bug where

type (~) = Either

    Yields a rather strange error:

    $ /opt/ghc/8.4.3/bin/ghci Bug2.hs
GHCi, version 8.4.3: http://www.haskell.org/ghc/  :? for help
Loaded GHCi configuration from /home/rgscott/.ghci
[1 of 1] Compiling Bug              ( Bug2.hs, interpreted )

Bug2.hs:4:1: error:
    Cannot redefine a Name retrieved by a Template Haskell quote: ~
  |
4 | type (~) = Either
  | ^^^^^^^^^^^^^^^^^

    Since Template Haskell certainly isn't involved here.

    The culprit is that (~) isn't listed within isBuiltInOcc_maybe. Patch incoming.

    Trac metadata
    Trac field Value
    Version 8.4.3
    Type Bug
    TypeOfFailure OtherFailure
    Priority normal
    Resolution Unresolved
    Component Compiler
    Test case
    Differential revisions
    BlockedBy
    Related
    Blocking
    CC
    Operating system
    Architecture
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