#10504: GHC panics with dsImpSpecs on SPECIALISE pragma with -fhpc enabled -------------------------------------+------------------------------------- Reporter: nh2 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by nh2): Ok, I found what makes the difference, `-O` is the culprit. With `-O`: {{{ $ ghc --make -O -isrc B A -Wall -fhpc [2 of 2] Compiling B ( src/B.hs, src/B.o ) src/B.hs:5:1: Warning: SPECIALISE pragma for non-overloaded function ‘myfun’ ghc: panic! (the 'impossible' happened) (GHC version 7.8.4 for x86_64-unknown-linux): dsImpSpecs main:A.myfun{v r0} [gid] Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} Without `-O`: {{{ $ ghc --make -isrc B A -Wall -fhpc [2 of 2] Compiling B ( src/B.hs, src/B.o ) }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10504#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler