[GHC] #13622: Regression: can't export constructor when conflicting, qualified constructor is also in scope
#13622: Regression: can't export constructor when conflicting, qualified constructor is also in scope -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 8.2.1-rc2 Keywords: | 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: -------------------------------------+------------------------------------- I ran into this regression when trying to compile the `ersatz` library with GHC 8.2.1-rc1. Here is a minimized example: {{{#!hs module Bug (Bits(Bits)) where import qualified Data.Bits as Bits newtype Bits = Bits Int }}} Compiling this with GHC 8.0.2 works fine, but with 8.2.1-rc1, you get this error: {{{ l$ /opt/ghc/8.2.1/bin/ghci Bug.hs GHCi, version 8.2.0.20170422: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/rgscott/.ghci [1 of 1] Compiling Bug ( Bug.hs, interpreted ) Bug.hs:1:13: error: • Ambiguous occurrence ‘Bits’ It could refer to either ‘Bits.Bits’, imported qualified from ‘Data.Bits’ at Bug.hs:3:1-34 or ‘Bits’, defined at Bug.hs:5:1 • In the export: Bits(Bits) | 1 | module Bug (Bits(Bits)) where | ^^^^^^^^^^ }}} Despite the fact that `Bits` isn't actually ambiguous, since the `Bits` from `Data.Bits` is qualified. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13622 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13622: Regression: can't export constructor when conflicting, qualified constructor is also in scope -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 8.2.1-rc2 Resolution: | Keywords: 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: | -------------------------------------+------------------------------------- Comment (by Iceland_jack): That example could be featured in a children's book -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13622#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13622: Regression: can't export constructor when conflicting, qualified constructor is also in scope -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 8.2.1-rc2 Resolution: | Keywords: 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: | -------------------------------------+------------------------------------- Comment (by mpickering): Does it work with HEAD? I think I fixed this in #13528 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13622#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13622: Regression: can't export constructor when conflicting, qualified constructor is also in scope -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 8.2.1-rc2 Resolution: | Keywords: 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: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): I experience the same bug with GHC HEAD. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13622#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13622: Regression: can't export constructor when conflicting, qualified constructor is also in scope -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 8.2.1-rc2 Resolution: | Keywords: 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 Lemming): * cc: Lemming (added) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13622#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13622: Regression: can't export constructor when conflicting, qualified constructor is also in scope -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 8.2.1-rc2 Resolution: | Keywords: 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: | -------------------------------------+------------------------------------- Comment (by mpickering): The problem is that name clash errors are reported too eagerly. Solution. 1. Extend `ChildLookupResult` to have a case for an ambiguous lookup 2. Prefer other options to ambiguous lookup in the monoid instance. 3. Use `addNameClashErr` when handling `ChildLookupResult` for the ambiguous case. I need to look carefully at whether all the uses of ambiguous names are recoverable or whether they should all be deferred to later. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13622#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13622: Regression: can't export constructor when conflicting, qualified constructor is also in scope -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: mpickering Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 8.2.1-rc2 Resolution: | Keywords: 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 mpickering): * owner: (none) => mpickering -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13622#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13622: Regression: can't export constructor when conflicting, qualified constructor is also in scope -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: mpickering Type: bug | Status: patch Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.2.1-rc2 Resolution: | Keywords: 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:D3515 Wiki Page: | -------------------------------------+------------------------------------- Changes (by mpickering): * status: new => patch * priority: high => highest * differential: => Phab:D3515 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13622#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13622: Regression: can't export constructor when conflicting, qualified constructor is also in scope -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: mpickering Type: bug | Status: patch Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.2.1-rc2 Resolution: | Keywords: 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:D3515 Wiki Page: | -------------------------------------+------------------------------------- Comment (by rwbarton):
The problem is that name clash errors are reported too eagerly.
I guess you must know what you are talking about, but this sounds weird to me since I can't see what name clash there is in the original program. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13622#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13622: Regression: can't export constructor when conflicting, qualified
constructor is also in scope
-------------------------------------+-------------------------------------
Reporter: RyanGlScott | Owner: mpickering
Type: bug | Status: patch
Priority: highest | Milestone: 8.2.1
Component: Compiler | Version: 8.2.1-rc2
Resolution: | Keywords:
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:D3515
Wiki Page: |
-------------------------------------+-------------------------------------
Comment (by Ben Gamari
#13622: Regression: can't export constructor when conflicting, qualified constructor is also in scope -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: mpickering Type: bug | Status: merge Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.2.1-rc2 Resolution: | Keywords: 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:D3515 Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: patch => merge -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13622#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13622: Regression: can't export constructor when conflicting, qualified constructor is also in scope -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: mpickering Type: bug | Status: closed Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.2.1-rc2 Resolution: fixed | Keywords: 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:D3515 Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: merge => closed * resolution: => fixed Comment: Merged with 0c845697e054b5e30e76a801c7ebc78238c8268a. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13622#comment:11 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13622: Regression: can't export constructor when conflicting, qualified constructor is also in scope -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: mpickering Type: bug | Status: closed Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.2.1-rc2 Resolution: fixed | Keywords: 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:D3515 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Lemming): Using `ghc-8.2.0.20170505` my problems are gone. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13622#comment:12 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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