typed holes inferring very polymorphic types

[Artem Pelenitsyn]

Hello Sreenidhi,

This looks like a valid Trac ticket to me. Maybe, open one?

--
Best, Artem

On Mon, 1 Oct 2018 at 13:25 Sreenidhi Nair <nair.sreenidhi at gmail.com> wrote:

> Hello,
>
> We tried the following code with ghc-8.6.1
>
> testFailure :: Char
> testFailure =
>   let x = Prelude.id _
>   in  x
>
> which gave the following suggestion
>
> /home/sreenidhi/Work/typeql/typeql-dbrecord/test/Test/Database/Postgres/Read/Combinator.hs:83:22:
> error:
>     • Found hole: _ :: a
>       Where: ‘a’ is a rigid type variable bound by
>                the inferred type of x :: a
>                at
> /home/sreenidhi/Work/typeql/typeql-dbrecord/test/Test/Database/Postgres/Read/Combinator.hs:83:7-22
>
> And then this
>
> testSuccess :: Char
> testSuccess = _
>
> which gave a much better suggestion
>
> /home/sreenidhi/Work/typeql/typeql-dbrecord/test/Test/Database/Postgres/Read/Combinator.hs:87:15:
> error:
>     • Found hole: _ :: Char
>     • In the expression: _
>       In an equation for ‘testSuccess’: testSuccess = _
>
> Is there any way to get better suggestions with 'let' version?
>
>
>
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