Re: [GHC] #15584: nonVoid is too conservative w.r.t. strict argument types

#15584: nonVoid is too conservative w.r.t. strict argument types -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: patch Priority: normal | Milestone: 8.8.1 Component: Compiler | Version: 8.5 Resolution: | Keywords: | PatternMatchWarnings Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple error/warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: #15305 | Differential Rev(s): Phab:D5116 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Ryan Scott ): In [changeset:"e68b439fe5de61b9a2ca51af472185c62ccb8b46/ghc" e68b439/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="e68b439fe5de61b9a2ca51af472185c62ccb8b46" Add a recursivity check in nonVoid Summary: Previously `nonVoid` outright refused to call itself recursively to avoid the risk of hitting infinite loops when checking recurisve types. But this is too conservative—we //can// call `nonVoid` recursively as long as we incorporate a way to detect the presence of recursive types, and bail out if we do detect one. Happily, such a mechanism already exists in the form of `checkRecTc`, so let's use it. Test Plan: make test TEST=T15584 Reviewers: simonpj, bgamari Reviewed By: simonpj Subscribers: rwbarton, carter GHC Trac Issues: #15584 Differential Revision: https://phabricator.haskell.org/D5116 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15584#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler