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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2018-08-20 09:48:41 +0100 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2018-08-20 14:21:38 +0100 |
| commit | 2dcebe69f07f9b4328bc3dc2131ccf2953ffa21b (patch) | |
| tree | 2106ada6f22bd198dc1891f1283740d26bf4047d /compiler/utils | |
| parent | a08b285f74cd49196feb0f819d70ad0508689da3 (diff) | |
| download | haskell-wip/T13064.tar.gz | |
Fix unused-import warningswip/T13064
This patch fixes a fairly long-standing bug (dating back to 2015) in
RdrName.bestImport, namely
commit 9376249b6b78610db055a10d05f6592d6bbbea2f
Author: Simon Peyton Jones <simonpj@microsoft.com>
Date: Wed Oct 28 17:16:55 2015 +0000
Fix unused-import stuff in a better way
In that patch got the sense of the comparison back to front, and
thereby failed to implement the unused-import rules described in
Note [Choosing the best import declaration] in RdrName
This led to Trac #13064 and #15393
Fixing this bug revealed a bunch of unused imports in libraries;
the ones in the GHC repo are part of this commit.
The two important changes are
* Fix the bug in bestImport
* Modified the rules by adding (a) in
Note [Choosing the best import declaration] in RdrName
Reason: the previosu rules made Trac #5211 go bad again. And
the new rule (a) makes sense to me.
In unravalling this I also ended up doing a few other things
* Refactor RnNames.ImportDeclUsage to use a [GlobalRdrElt] for the
things that are used, rather than [AvailInfo]. This is simpler
and more direct.
* Rename greParentName to greParent_maybe, to follow GHC
naming conventions
* Delete dead code RdrName.greUsedRdrName
* Slightly change the spec of the unused function
HsImpExpr.ieLWrappedName, and use it in RnNames.findImportUsage
Diffstat (limited to 'compiler/utils')
| -rw-r--r-- | compiler/utils/OrdList.hs | 1 | ||||
| -rw-r--r-- | compiler/utils/Outputable.hs | 1 |
2 files changed, 0 insertions, 2 deletions
diff --git a/compiler/utils/OrdList.hs b/compiler/utils/OrdList.hs index a5739764d4..e4a34ac693 100644 --- a/compiler/utils/OrdList.hs +++ b/compiler/utils/OrdList.hs @@ -19,7 +19,6 @@ import GhcPrelude import Outputable -import Data.Semigroup ( Semigroup ) import qualified Data.Semigroup as Semigroup infixl 5 `appOL` diff --git a/compiler/utils/Outputable.hs b/compiler/utils/Outputable.hs index 929c7f3d58..f8f1283b4d 100644 --- a/compiler/utils/Outputable.hs +++ b/compiler/utils/Outputable.hs @@ -108,7 +108,6 @@ import Panic import GHC.Serialized import GHC.LanguageExtensions (Extension) -import Control.Exception (finally) import Data.ByteString (ByteString) import qualified Data.ByteString as BS import Data.Char |