Failed kind inference in class declaration (regression error)

Consider the following code:

{-# LANGUAGE MultiParamTypeClasses
 #-}

class Foo a b

class Foo a b => Bar a b where
    baz :: a b

This compiles fine in 7.2.1 but fails in 7.4.1-rc1, with the following error:

Sandbox.hs:7:12:
    `a' is applied to too many type arguments
    In the type `a b'
    In the class declaration for `Bar'

Trac metadata

Trac field	Value
Version	7.4.1-rc1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler (Type checker)
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