The GHCi :type command seems to discard some type errors
Summary
The GHCi command :type
will occasionally return an empty result.
Steps to reproduce
stack --resolver=lts-16.12 repl
Prelude> :set -XTypeApplications
Prelude> :type length
length :: Foldable t => t a -> Int
Prelude> :type length @[]
length @[] :: [a] -> Int
Prelude> :type length @Int -- Notice the empty response
Prelude> length @Int
<interactive>:6:9: error:
• Expected kind ‘* -> *’, but ‘Int’ has kind ‘*’
• In the type ‘Int’
In the expression: length @Int
In an equation for ‘it’: it = length @Int
Expected behavior
The :type length @Int
should produce an error.
Environment
- GHC version used: GHC 8.8.4
Optional:
- Operating System: OS x