GHC writes:

#13646: strict patterns with no bindings (e.g. `let !() = ...`) trigger -Wunused- pattern-binds -------------------------------------+------------------------------------- Reporter: exphp | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+-------------------------------------

Comment (by simonpj):

Yes I see the point. Perhaps we should suppress this warning if the pattern has an outmost bang.

Does anyone object?

Sounds reasonable to me.