#14594: 2 modules / 2500LOC takes nearly 3 minutes to build -------------------------------------+------------------------------------- Reporter: schyler | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | performance bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I tested this from a brand new MacBook 15" with 8 threads x 2.8 GHz Intel Core i7 / 16 GB RAM on OS X: {{{ $ time stack build WARNING: /Users/kvanb/git/github-webhooks/github-webhooks.cabal was generated with a newer version of hpack, please upgrade and try again. github-webhooks-1.0.0: unregistering (local file changes: github- webhooks.cabal package.yaml spec/DecodeEventsSpec.hs spec/Spec.hs src/GitHub/Data/Webhooks...) github-webhooks-1.0.0: configure (lib) Configuring github-webhooks-1.0.0... github-webhooks-1.0.0: build (lib) Preprocessing library github-webhooks-1.0.0... [1 of 3] Compiling Paths_github_webhooks ( .stack- work/dist/x86_64-osx/Cabal-1.24.2.0/build/autogen/Paths_github_webhooks.hs, .stack-work/dist/x86_64-osx/Cabal-1.24.2.0/build/Paths_github_webhooks.o ) [2 of 3] Compiling GitHub.Data.Webhooks.Payload ( src/GitHub/Data/Webhooks/Payload.hs, .stack- work/dist/x86_64-osx/Cabal-1.24.2.0/build/GitHub/Data/Webhooks/Payload.o ) [3 of 3] Compiling GitHub.Data.Webhooks.Events ( src/GitHub/Data/Webhooks/Events.hs, .stack- work/dist/x86_64-osx/Cabal-1.24.2.0/build/GitHub/Data/Webhooks/Events.o ) github-webhooks-1.0.0: copy/register Installing library in /Users/kvanb/git/github-webhooks/.stack- work/install/x86_64-osx/lts-9.18/8.0.2/lib/x86_64-osx-ghc-8.0.2/github- webhooks-1.0.0-LDmeffpkXvwH6ZXCPE95ke Registering github-webhooks-1.0.0... real 2m49.342s user 2m42.441s sys 0m5.805s }}} Source code has about 30 derivations of the form: {{{#!hs type IssueState = Text data HookIssue = HookIssue { whIssueUrl :: !URL , whIssueLabelsUrl :: !URL , whIssueCommentsUrl :: !URL , whIssueEventsUrl :: !URL , whIssueHtmlUrl :: !URL , whIssueId :: !Int , whIssueNumber :: !Int , whIssueTitle :: !Text , whIssueUser :: !HookUser , whIssueLabels :: !(Vector HookIssueLabels) , whIssueState :: IssueState , whIssueIsLocked :: !Bool , whIssueAssignee :: !(Maybe HookUser) , whIssueMilestone :: !(Maybe HookMilestone) , whIssueCommentCount :: !Int , whIssueCreatedAt :: !UTCTime , whIssueUpdatedAt :: !UTCTime , whIssueClosedAt :: !(Maybe UTCTime) , whIssueBody :: !Text } deriving (Eq, Show, Typeable, Data, Generic) instance NFData HookIssue where rnf = genericRnf }}} Steps to reproduce 1. clone https://github.com/onrock-eng/github-webhooks 2. checkout sha 40a7ecc3a5845717055ee372b89e645a498cf1e2 3. time stack build This is really ''really'' ''**really**'' slow. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14594 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler