Operator (!) causes weird pretty printing and parsing

class Key key where
  data TotalMap key :: Type -> Type
  (!) :: TotalMap key val -> (key -> val)

instance Key Bool where
  data TotalMap Bool val = BoolMap val val
  (!) :: TotalMap Bool val -> (Bool -> val)
  (BoolMap f _) ! False = f

puts unnecessary parentheses around the wildcard pattern:

tf6t.hs:14:3-23: error: …
    Parse error in pattern: (BoolMap f (_))
Compilation failed.

and with no parentheses

  BoolMap f _ ! False = f

it talks about missing method, pattern bindings and doesn't list a space between ! and False:

tf6t.hs:13:3-5: error: …
    The class method signature for ‘!’ lacks an accompanying binding
      (The class method signature must be given where ‘!’ is declared)
tf6t.hs:14:3-25: error: …
    Pattern bindings (except simple variables) not allowed in instance declaration:
      BoolMap f _ !False = f
Compilation failed.

All of these issues go away if the operator is called something other than !, it works if written prefix

  (!) (BoolMap f _) False = f

Trac metadata

Trac field	Value
Version	8.0.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler (Parser)
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