Allow applying type to label
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE TypeApplications #-}
{-# LANGUAGE OverloadedLabels #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE DataKinds #-}
import GHC.TypeLits
import GHC.OverloadedLabels
instance IsLabel "answer" Int where
fromLabel _ = 42
answer :: IsLabel "answer" a => a
answer = #answer
The follow works:
>>> answer @Int
42
but fails with a label:
>>> #answer @Int
<interactive>:...:1: error:
• Cannot not apply expression of type ‘t0’
to a visible type argument ‘Int’
• In the expression: #answer @Int
In an equation for ‘it’: it = #answer @Int
Trac metadata
Trac field | Value |
---|---|
Version | 7.10.3 |
Type | FeatureRequest |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |