#10934: Iface type variable out of scope -------------------------------------+------------------------------------- Reporter: mjmrotek | Owner: Type: bug | Status: new Priority: high | Milestone: Component: Compiler | Version: 7.10.2 Resolution: | Keywords: interface Operating System: Linux | Architecture: Type of failure: Compile-time | Unknown/Multiple crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): -------------------------------------+------------------------------------- Changes (by thomie): * priority: normal => high Comment: Reproducible with HEAD (ghc-7.11.20151002), see attachments. The cabal file doesn't pull in any dependencies. {{{ $ cabal configure ... $ cabal build Building keyvalue-0.0.0.0... Preprocessing library keyvalue-0.0.0.0... [1 of 2] Compiling Vinyl ( Vinyl.hs, dist/build/Vinyl.o ) [2 of 2] Compiling KeyValue ( KeyValue.hs, dist/build/KeyValue.o ) In-place registering keyvalue-0.0.0.0... $ ghc -package-db dist/package.conf.inplace -O -fforce-recomp -c T10934.hs /home/thomas/T10934/dist/build/KeyValue.hi Declaration for missing1: Iface type variable out of scope: k Cannot continue after interface file error }}} Note that the cabal build step is needed to trigger the bug. Running `ghc --make -O -outputdir=/tmp -fforce-recomp T10934.hs` works fine. Compiling `KeyValue.hs` with `-dcore-lint` results in Core Lint errors: {{{ $ ghc -O -outputdir=/tmp -dcore-lint -fforce-recomp KeyValue.hs [1 of 2] Compiling Vinyl ( Vinyl.hs, /tmp/Vinyl.o ) [2 of 2] Compiling KeyValue ( KeyValue.hs, /tmp/KeyValue.o ) *** Core Lint errors : in result of Simplifier *** KeyValue.hs:20:19: Warning: [in body of lambda with binder f_aBJ :: k_aBI -> *] @ (k_aBI :: BOX) is out of scope }}} Commenting out the `PolyKinds` extension in `KeyValue.hs` makes the bug go away. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10934#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler