GHC shouldn't expand constraint synonyms
{-# LANGUAGE ConstraintKinds #-}
type ShowX = Show
showX :: ShowX a => a -> String
showX = showIf I now ask for the type of showX, I get:
*Main> :t showX
showX :: Show a => a -> StringTrac metadata
| Trac field | Value |
|---|---|
| Version | 7.8.2 |
| Type | FeatureRequest |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |