#8095: TypeFamilies painfully slow -------------------------------------+------------------------------------- Reporter: | Owner: MikeIzbicki | Status: new Type: bug | Milestone: 7.10.1 Priority: high | Version: 7.6.3 Component: Compiler | Keywords: (Type checker) | Architecture: Unknown/Multiple Resolution: | Difficulty: Unknown Operating System: | Blocked By: Unknown/Multiple | Related Tickets: 5321 Type of failure: Compile- | time performance bug | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Changes (by thomie): * priority: normal => high * milestone: => 7.10.1 Comment: Running the first example from the description with ghc HEAD: {{{ $ ./Types 200 a a > test.hs && ghc-7.9.20141119 test.hs > /dev/null -fcontext-stack=250 +RTS -t test.hs:12:10: Type function application stack overflow; size = 201 Use -ftype-function-depth=N to increase stack size to N Replicate1 'Zero () ~ '[] In the instance declaration for ‘Class (Data xs)’ <<ghc: 3459540512 bytes, 388 GCs, 70724196/419708144 avg/max bytes residency (12 samples), 815M in use, 0.001 INIT (0.001 elapsed), 36.325 MUT (36.475 elapsed), 5.933 GC (5.971 elapsed) :ghc>> }}} That's a lot of bytes. Adding `-ftype-function-depth=250` doesn't help: ever increasing memory usage until I have to kill the process. I did not try any of the other examples. This looks like a regression, setting priority to high. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8095#comment:3> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler