Ticket #3911 (closed bug: fixed)
HughesPJ.vcat should behave like 'foldr ($$) empty', not like 'foldr ($+$) empty'
|Reported by:||benedikt||Owned by:||igloo|
|Type of failure:||Incorrect result at runtime||Difficulty:|
|Test Case:||T3911||Blocked By:|
The performance tuning for libraries/pretty applied in June 2008
Tue Jun 24 12:37:15 BST 2008 firstname.lastname@example.org * fillNB bug, lazy vcat
accidentally changed the behavior of vcat to foldr ($+$) empty, although it should be foldr ($$) empty, according to the documentation. Fixing this is simple (patch attached).
hunk ./Text/PrettyPrint/HughesPJ.hs 497 -vcat = reduceAB . foldr (above_' True) empty +vcat = reduceAB . foldr (above_' False) empty
It would be nice to add a test case, but I'm not sure where to put it.