[Haskell-cafe] Significant changes in -Wall for GHC 7.10

Omari Norman omari at smileystation.com
Tue May 5 14:54:59 UTC 2015


I noticed some significant changes to the flags included with -Wall in GHC
7.10.  Many flags that were previously included in -Wall are now not
included.  These include:

-fwarn-type-defaults
-fwarn-name-shadowing
-fwarn-missing-signatures
-fwarn-hi-shadowing
-fwarn-orphans
-fwarn-unused-do-bind
-fwarn-trustworthy-safe

I can't find any mention in the release notes of this change in behavior.

I was wondering what the rationale is for these changes?  Any link to
relevant discussion would be appreciated if it exists.

Also, what opinion do people have?  I previously kept my code -Wall clean,
but sometimes that would be a pain.  For instance I would munge local names
so they wouldn't trigger -fwarn-name-shadowing, and I would add signatures
to integers so they wouldn't trigger -fwarn-type-defaults.  In fact, I only
noticed this change in behavior in 7.10 because I was considering dumping
-Wall, and when I looked at the 7.10 manual I saw that it does not enable
-fwarn-name-shadowing.  (I still use 7.8 but Google pulled the 7.10
manual.)  Does this change indicate that people were finding -Wall too
onerous and, thus, not using it?

I do remember reading complaints about -fwarn-unused-do-bind being added to
-Wall, but I previously felt dirty about name shadowing though I wondered
if munging names to avoid shadowing was actually worse.
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