tc_hs_type: bang : The impossible happened

A simple data structure with bang patterns like the following:

data MyType
    = MyType
        { a :: !Int
        , b :: !Maybe Int
        }

results in:

ghc: panic! (the 'impossible' happened)
  (GHC version 7.6.1 for x86_64-unknown-linux):
        tc_hs_type: bang

Adding parentheses around the "Maybe Int" like this:

data MyType
    = MyType
        { a :: !Int
        , b :: !(Maybe Int)
        }

is accepted, but it would be nice if the former example printed a syntax error or some sort of other warning rather than just a panic.

Trac metadata

Trac field	Value
Version	7.6.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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