Opened 5 years ago

Closed 5 years ago

#7089 closed bug (worksforme)

-fwarn-unused-do-bind with type families

Reported by: dag Owned by:
Priority: normal Milestone:
Component: Compiler Version: 7.4.1
Keywords: Cc:
Operating System: Unknown/Multiple Architecture: Unknown/Multiple
Type of failure: Incorrect warning at compile-time Test Case:
Blocked By: Blocking:
Related Tickets: Differential Rev(s):
Wiki Page:


When using acid-state, I get warnings for "unused do binds" from functions that return () but whose type involve asssociated types:

update :: UpdateEvent event => AcidState (EventState event) -> event -> IO (EventResult event)

Shouldn't GHC be able to deduce when EventResult resolves to unit?

Change History (4)

comment:1 Changed 5 years ago by dag

Type of failure: None/UnknownIncorrect warning at compile-time

comment:2 Changed 5 years ago by simonpj

difficulty: Unknown

Perhpas you can give a small standalone reproducible test case?

comment:3 Changed 5 years ago by dag

I'm unable to reproduce this without acid-state, so something more complicated is going on. Investigating.

comment:4 Changed 5 years ago by igloo

Resolution: worksforme
Status: newclosed

As we have no way to reproduce this, I'm closing it. Please reopen (or open a new ticket) if you find a way to reproduce it.

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