[GHC] #14173: GHC hangs during type-checking
#14173: GHC hangs during type-checking -------------------------------------+------------------------------------- Reporter: lightandlight | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Keywords: | Operating System: Linux Architecture: x86_64 | Type of failure: Compile-time (amd64) | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- GHC 8.0.2 doesn't terminate when type checking this file: {{{#!hs import Control.Lens import Data.Functor.Compose traverseCompose :: (a -> f b) -> g a -> f (h _) traverseCompose = _Wrapping Compose . traverse }}} This is the smallest type signature I could find that still causes the problem. GHCi infers the type without issue, and when I annotate it with the correct type signature, the file is successfully compiled. Using base-4.9.1.0, lens-4.15.1, and transformers-0.5.2.0 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14173 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#14173: GHC hangs during type-checking -------------------------------------+------------------------------------- Reporter: lightandlight | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by lightandlight): * version: 8.2.1 => 8.0.2 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14173#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#14173: GHC hangs during type-checking -------------------------------------+------------------------------------- Reporter: lightandlight | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by bgamari): With 8.2.1 this fails with, {{{ hi.hs:5:19: error: • Reduction stack overflow; size = 201 When simplifying the following type: g ~ Compose f'0 g'0 Use -freduction-depth=0 to disable this check (any upper bound you could choose might fail unpredictably with minor updates to GHC, so disabling the check is recommended if you're sure that type checking should terminate) • In the expression: _Wrapping Compose . traverse In an equation for ‘traverseCompose’: traverseCompose = _Wrapping Compose . traverse }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14173#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#14173: GHC hangs during type-checking -------------------------------------+------------------------------------- Reporter: lightandlight | Owner: (none) Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: duplicate | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: #14172 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * status: new => closed * resolution: => duplicate * related: => #14172 Comment: Hm, this seems to have been submitted twice somehow. In any case, closing as a duplicate of #14172. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14173#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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