[Haskell-cafe] [] == []

[Lyndon Maydwell]

This looks like a great opportunity to try out the new holes functionality:

[Prelude] λ [] == _what

<interactive>:3:7:
    Found hole ‘_what’ with type: [t0]
    Where: ‘t0’ is an ambiguous type variable
    Relevant bindings include it :: Bool (bound at <interactive>:3:1)
    In the second argument of ‘(==)’, namely ‘_what’
    In the expression: [] == _what
    In an equation for ‘it’: it = [] == _what


Looks like it defaults to [Bool]!

Correct me if I'm wrong :)


 - Lyndon


On Tue, Mar 10, 2015 at 1:33 PM, Rustom Mody <rustompmody at gmail.com> wrote:

> My impression is that earlier
> [] == []
> used to give a type error.  Now it gives True.
>
> So
> 1. Which instance of == is being used?
> 2. Is there some option controlling this behavior?
>
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