Opened 3 years ago

Closed 3 years ago

Last modified 3 years ago

#9317 closed bug (fixed)

Add PolyKinds extension to Data.Monoid

Reported by: bernalex Owned by:
Priority: low Milestone: 7.10.1
Component: libraries/base Version: 7.8.2
Keywords: Cc: hvr, ekmett
Operating System: Unknown/Multiple Architecture: Unknown/Multiple
Type of failure: None/Unknown Test Case:
Blocked By: Blocking:
Related Tickets: Differential Rev(s): Phab:D70
Wiki Page:

Attachments (1)

0001-Add-PolyKinds-extension-to-Data.Monoid.patch (1.9 KB) - added by bernalex 3 years ago.

Download all attachments as: .zip

Change History (7)

comment:1 Changed 3 years ago by bernalex

Status: newpatch

comment:2 Changed 3 years ago by ekmett

This was very much an accidental regression, not something consciously done. Makes sense to fix it.

comment:3 Changed 3 years ago by bernalex

Differential Rev(s): Phab:D70

comment:4 Changed 3 years ago by Austin Seipp <austin@…>

In 18b2c46773eccb974bdd042a2f400edd23e193d7/ghc:

Add PolyKinds extension to Data.Monoid

Carl Howells pointed out[0] that the `Monoid` instance for
`Data.Proxy.Proxy` is only defined for types with kind *.

This is a very mild change. Furthermore, Edward Kmett revealed[1] that
it was supposed to be there all along -- the extension simply got lost
in commit 1d1ff77aaa09efaddc8cfe0dcf92d6763297cf11, as pointed out by
Adam Vogt[2]. This used to be correct in GHC 7.6, so this commit fixes a

This addresses #9317.

[0] <>.
[1] <>.
[2] <>.

Signed-off-by: Alexander Berntsen <>

Test Plan: See [0]

Reviewers: austin, hvr, ekmett

Reviewed By: austin, hvr, ekmett

Subscribers: phaskell, simonmar, relrod, carter

Differential Revision:

comment:5 Changed 3 years ago by thoughtpolice

Resolution: fixed
Status: patchclosed

Merged, thanks!

comment:6 Changed 3 years ago by thoughtpolice

Milestone: 7.10.1
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