Defining an infix operator `!` is recognised as a bang pattern

I tried to define an operator called (!) like this:

(!) :: a -> b -> ()
_ ! _ = ()

But hlint gives me a parse error, while GHC accepts the codes just fine:

test.hs:4:1: Error: Parse error
Found:
    (!) :: a -> b -> ()
  > _ ! _ = ()

I think hlint (haskell-src-exts?) thinks ! _ is a bang pattern and thus expects the first _ to be a valid function name, as demonstrated by this code:

(!) :: a -> () -> ()
a ! () = ()

which gives the following hint:

test.hs:4:3: Warning: Redundant bang pattern
Found:
  !()
Perhaps:
  ()

Run hlint on a test.hs containing the two operator definitions shown in the issue, and read the relevant parsing behavior in hlint or haskell-src-exts. Done means the valid infix operator definition is accepted without a parse error or an incorrect bang-pattern warning, while genuine bang patterns remain handled correctly.