[GHC] #11607: ApplicativeDo easily foiled with `pure`
#11607: ApplicativeDo easily foiled with `pure` -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: high | Milestone: 8.0.1 Component: Compiler | Version: 8.0.1-rc2 (Type checker) | Keywords: ApplicativeDo | Operating System: Unknown/Multiple Architecture: | Type of failure: GHC rejects Unknown/Multiple | valid program Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- `ApplicativeDo` fails to desugar `do` blocks ending with `pure`. For instance, {{{#!hs {-# LANGUAGE ApplicativeDo #-} {-# LANGUAGE GeneralizedNewtypeDeriving #-} newtype MaybeA a = MaybeA (Maybe a) deriving (Show, Functor, Applicative) main = print $ do x <- MaybeA $ Just 42 pure x }}} However, if the final `pure` is changed to `return` things work as expected. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11607 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#11607: ApplicativeDo easily foiled with `pure` -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: high | Milestone: 8.0.1 Component: Compiler (Type | Version: 8.0.1-rc2 checker) | Resolution: | Keywords: ApplicativeDo Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by ocharles): * cc: ocharles (added) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11607#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#11607: ApplicativeDo easily foiled with `pure` -------------------------------------+------------------------------------- Reporter: bgamari | Owner: bgamari Type: bug | Status: new Priority: high | Milestone: 8.0.1 Component: Compiler (Type | Version: 8.0.1-rc2 checker) | Resolution: | Keywords: ApplicativeDo Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * owner: => bgamari -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11607#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#11607: ApplicativeDo easily foiled with `pure` -------------------------------------+------------------------------------- Reporter: bgamari | Owner: bgamari Type: bug | Status: patch Priority: high | Milestone: 8.0.1 Component: Compiler (Type | Version: 8.0.1-rc2 checker) | Resolution: | Keywords: ApplicativeDo Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D1931 Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: new => patch * differential: => Phab:D1931 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11607#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#11607: ApplicativeDo easily foiled with `pure` -------------------------------------+------------------------------------- Reporter: bgamari | Owner: bgamari Type: bug | Status: patch Priority: high | Milestone: 8.0.1 Component: Compiler (Type | Version: 8.0.1-rc2 checker) | Resolution: | Keywords: ApplicativeDo Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: ado/T11607 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D1931 Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * testcase: => ado/T11607 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11607#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#11607: ApplicativeDo easily foiled with `pure` -------------------------------------+------------------------------------- Reporter: bgamari | Owner: bgamari Type: bug | Status: patch Priority: high | Milestone: 8.0.1 Component: Compiler (Type | Version: 8.0.1-rc2 checker) | Resolution: | Keywords: ApplicativeDo Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: ado/T11607 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D1931 Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): Yikes! there is no user-manual documentation about the magical behaviour of `return`. Adding more magic (`pure` or `return`) sees uncool. E.g. if I have {{{ }}} then using `blah` will surprisingly fail. Simon M? Regardless whatever the behaviour is ought to be carefully specified in the user manual. So I'm not complaining about Phab:D1931, but rather asking for proper documentation. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11607#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#11607: ApplicativeDo easily foiled with `pure`
-------------------------------------+-------------------------------------
Reporter: bgamari | Owner: bgamari
Type: bug | Status: patch
Priority: high | Milestone: 8.0.1
Component: Compiler (Type | Version: 8.0.1-rc2
checker) |
Resolution: | Keywords: ApplicativeDo
Operating System: Unknown/Multiple | Architecture:
Type of failure: GHC rejects | Unknown/Multiple
valid program | Test Case: ado/T11607
Blocked By: | Blocking:
Related Tickets: | Differential Rev(s): Phab:D1931
Wiki Page: |
-------------------------------------+-------------------------------------
Comment (by Ben Gamari
#11607: ApplicativeDo easily foiled with `pure` -------------------------------------+------------------------------------- Reporter: bgamari | Owner: bgamari Type: bug | Status: merge Priority: high | Milestone: 8.0.1 Component: Compiler (Type | Version: 8.0.1-rc2 checker) | Resolution: | Keywords: ApplicativeDo Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: ado/T11607 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D1931 Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: patch => merge -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11607#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#11607: ApplicativeDo easily foiled with `pure` -------------------------------------+------------------------------------- Reporter: bgamari | Owner: bgamari Type: bug | Status: closed Priority: high | Milestone: 8.0.1 Component: Compiler (Type | Version: 8.0.1-rc2 checker) | Resolution: fixed | Keywords: ApplicativeDo Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: ado/T11607 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D1931 Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: merge => closed * resolution: => fixed Comment: Merged as 32e2d58c8b767d791dd79f5e77f39a776f784054. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11607#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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