#15393: Regression: Detection of unused imports is imprecise (since GHC 8.0.1) -------------------------------------+------------------------------------- Reporter: SimonHengel | Owner: (none) Type: bug | Status: closed Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.1 Resolution: duplicate | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple error/warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: #15393 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by jrp): Not sure whether this commit is breaking the current {{{validate --slow}}} build: {{{ "inplace/bin/ghc-stage1" -hisuf p_hi -osuf p_o -hcsuf p_hc -static -prof -eventlog -O0 -H64m -Wall -fllvm-fill-undef-with-garbage -Werror -this-unit-id containers-0.6.0.1 -hide-all-packages -i -ilibraries/containers/. -ilibraries/containers/dist-install/build -Ilibraries/containers/dist-install/build -ilibraries/containers/dist- install/build/./autogen -Ilibraries/containers/dist- install/build/./autogen -Ilibraries/containers/include -Ilibraries/containers/dist-install/build/include -optP-include -optPlibraries/containers/dist-install/build/./autogen/cabal_macros.h -package-id array-0.5.2.0 -package-id base-4.12.0.0 -package-id deepseq-1.4.4.0 -package-id ghc-prim-0.5.3 -O2 -Wall -XHaskell98 -O -dcore-lint -dno-debug-output -no-user-package-db -rtsopts -Wno- deprecated-flags -Wnoncanonical-monad-instances -odir libraries/containers/dist-install/build -hidir libraries/containers/dist- install/build -stubdir libraries/containers/dist-install/build -c libraries/containers/./Data/Sequence/Internal.hs -o libraries/containers /dist-install/build/Data/Sequence/Internal.p_o -dyno libraries/containers /dist-install/build/Data/Sequence/Internal.dyn_o libraries/containers/Data/Set/Internal.hs:239:1: error: [-Wunused-imports, -Werror=unused-imports] The import of ‘<>’ from module ‘Data.Semigroup’ is redundant | 239 | import Data.Semigroup (Semigroup((<>), stimes), stimesIdempotentMonoid) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ make[1]: *** [libraries/containers/ghc.mk:4: libraries/containers/dist- install/build/Data/Set/Internal.p_o] Error 1 make[1]: *** Waiting for unfinished jobs.... libraries/containers/Data/IntSet/Internal.hs:198:1: error: [-Wunused- imports, -Werror=unused-imports] The import of ‘<>’ from module ‘Data.Semigroup’ is redundant | 198 | import Data.Semigroup (Semigroup((<>), stimes), stimesIdempotentMonoid) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ libraries/containers/Data/IntSet/Internal.hs:220:1: error: [-Wunused- imports, -Werror=unused-imports] The import of ‘Data.Foldable’ is redundant except perhaps to import instances from ‘Data.Foldable’ To import instances alone, use: import Data.Foldable() | 220 | import Data.Foldable (Foldable()) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ make[1]: *** [libraries/containers/ghc.mk:4: libraries/containers/dist- install/build/Data/IntSet/Internal.p_o] Error 1 make: *** [Makefile:128: all] Error 2 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15393#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler