Template Haskell - How to lookup type operator name? -

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how lookup type operator name? not work:

issueth.hs:

{-# language templatehaskell #-} module issueth import language.haskell.th  f :: q [dec] f =     n <- lookuptypename "ghc.typelits.*"     return []

issue.hs:

{-# language templatehaskell #-} module issue import issueth  $f

ghc issue.hs fails message: 

pattern match failure in expression @ issueth.hs

replacing "ghc.typelits.*" "ghc.typelits.(*)" or "*" doesn't work either.

i guess have enough brief answer. alas found reason problem, not how solve it.

my testing shows lookuptypename does support type operators, if start :.

originally requirement, in analogy infix data constructors, lifted allow things arithmetical type operators in ghc.typelits. (the downside can no longer have type operator variables, once popular things arrow code.)

presumably lookuptypename not updated take account, , have filed bug report this.

edit: fix has been made, , should in upcoming ghc 8.2.1.


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