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authorNathan Collins <nathan.collins@gmail.com>2019-05-21 13:44:55 -0400
committerMarge Bot <ben+marge-bot@smart-cactus.org>2019-05-31 23:55:49 -0400
commit1d43d4a3e45d86261fa63591e99749cb7d3f68ed (patch)
tree14ac49ef975a2a4fd9c6214f202da16688f4673a
parent0e0d87da2fd25e2fb255417fcb15f93f508c1250 (diff)
downloadhaskell-1d43d4a3e45d86261fa63591e99749cb7d3f68ed.tar.gz
Improve ThreadId Show instance
By making it include parens when a derived instance would. For example, this changes the (hypothetical) code `show (Just (ThreadId 3))` to produce `"Just (ThreadId 3)"` instead of the current `"Just ThreadId 3"`.
-rw-r--r--libraries/base/GHC/Conc/Sync.hs4
1 files changed, 2 insertions, 2 deletions
diff --git a/libraries/base/GHC/Conc/Sync.hs b/libraries/base/GHC/Conc/Sync.hs
index 5c3e63a8e3..87491993f8 100644
--- a/libraries/base/GHC/Conc/Sync.hs
+++ b/libraries/base/GHC/Conc/Sync.hs
@@ -113,7 +113,7 @@ import GHC.IORef
import GHC.MVar
import GHC.Ptr
import GHC.Real ( fromIntegral )
-import GHC.Show ( Show(..), showString )
+import GHC.Show ( Show(..), showParen, showString )
import GHC.Stable ( StablePtr(..) )
import GHC.Weak
@@ -145,7 +145,7 @@ This misfeature will hopefully be corrected at a later date.
-- | @since 4.2.0.0
instance Show ThreadId where
- showsPrec d t =
+ showsPrec d t = showParen (d >= 11) $
showString "ThreadId " .
showsPrec d (getThreadId (id2TSO t))