[GHC] #10772: Type operator variable in prefix notation fails

[GHC]

#10772: Type operator variable in prefix notation fails
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        Reporter:  nomeata           |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.11
  (Parser)                           |
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Description changed by nomeata:

Old description:

> Hi,
>
> I’m not sure if this is me misreading the documentation at
> https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/data-
> type-extensions.html#infix-tycons (in which case maybe the wording can be
> improved) or an actual bug. But I would have expected this code
>
> {{{
> foo :: [(*)] -> Maybe (*)
> foo _ = Nothing
> }}}
>
> to be equivalent to
>
> {{{
> foo :: [(*)] -> Maybe (*)
> foo _ = Nothing
> }}}
>
> at least with `-XNoTypeOperators`. But independent of that flag, with GHC
> HEAD and 7.8, I get
> {{{
> /tmp/foo.hs:1:9: error: Not in scope: type constructor or class ‘*’
> }}}

New description:

 Hi,

 I’m not sure if this is me misreading the documentation at
 https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/data-type-
 extensions.html#infix-tycons (in which case maybe the wording can be
 improved) or an actual bug. But I would have expected this code

 {{{
 foo :: [(*)] -> Maybe (*)
 foo _ = Nothing
 }}}

 to be equivalent to

 {{{
 foo :: [a] -> Maybe a
 foo _ = Nothing
 }}}

 at least with `-XNoTypeOperators`. But independent of that flag, with GHC
 HEAD and 7.8, I get
 {{{
 /tmp/foo.hs:1:9: error: Not in scope: type constructor or class ‘*’
 }}}

--

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10772#comment:1>
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