#5041: Incorrect Read deriving for MagicHash constructors -------------------------------------+------------------------------------- Reporter: dolio | Owner: (none) Type: bug | Status: new Priority: low | Milestone: ⊥ Component: Compiler | Version: 7.0.2 Resolution: | Keywords: deriving Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: | deriving/should_run/T5041 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Ryan Scott <ryan.gl.scott@…>): In [changeset:"d5577f44eaf3b9dfdfc77828038782bf818c176a/ghc" d5577f44/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="d5577f44eaf3b9dfdfc77828038782bf818c176a" Special-case record fields ending with hash when deriving Read Summary: In commit dbd81f7e86514498218572b9d978373b1699cc5b, a regression was inadvertently introduced which caused derived `Read` instances for record data types with fields ending in a `#` symbol (using `MagicHash`) would no longer parse on valid output. This is ultimately due to the same reasons as #5041, as we cannot parse a field name like `foo#` as a single identifier. We fix this issue by employing the same workaround as in #5041: first parse the identifier name `foo`, then then symbol `#`. This is accomplished by the new `readFieldHash` function in `GHC.Read`. This will likely warrant a `base-4.11.1.0` release. Test Plan: make test TEST=T14918 Reviewers: tdammers, hvr, bgamari Reviewed By: bgamari Subscribers: rwbarton, thomie, carter GHC Trac Issues: #14918 Differential Revision: https://phabricator.haskell.org/D4502 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5041#comment:11> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler