Fix MonadFail warnings

#10751 (closed) implements the MonadFail warning mechanism.

Using -fwarn-missing-monadfail-instance, GHC's internal warnings created by the patch can be shown and fixed.

A second pass with -XMonadFailDesugaring then provides a hard check on whether any issues remain, by switching on the new desugaring mechanism properly.

Trac metadata

Trac field	Value
Version	7.11
Type	Task
TypeOfFailure	OtherFailure
Priority	low
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture

mentioned in issue #11086 (closed)

mentioned in issue #11087 (closed)

mentioned in issue #11088 (closed)

mentioned in issue #11089 (closed)

mentioned in issue #11090 (closed)

changed milestone to %8.2.1

changed weight to 3

added Ttask Trac import labels

Trac metadata

Trac field	Value
BlockedBy	- → #10751 (closed)

Trac metadata

Trac field	Value
BlockedBy	#10751 (closed) →

Trac metadata

Trac field	Value
TypeOfFailure	OtherFailure → IncorrectWarning

changed milestone to %8.4.1

Given that 8.2.1-rc1 is imminent, I'm bumping these off to the 8.4

These tasks won't happen for 8.4 and have been sitting at low priority for quite some time. Consequently I am un-milestoning them. Don't let this stop you, the interested reader, from picking one up, however.

closed

I believe this is done.

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedFixed

added Plow label