#15702: "-main-is" flag is broken for recent ghc-head -------------------------------------+------------------------------------- Reporter: terrorjack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.6.1 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Incorrect | (amd64) error/warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by cdsmith): Arguably, I think this should never have worked in the first place. Here, Main.hs is relying on the default header to export `main` because of its name, even though `main` is no longer the entry point for this program. Adding an explicit export would fix it. If this was done in existing code, though, this does mean there's a backward-compatibility problem for that patch. That's unfortunate. The error message is also weird. There's a special error message for the `main` case that says something like "The IO action main is not defined in module Main", but `-main-is` seems to disable it and fall back to a generic "Not in scope". (This was pre-existing behavior, though. It's not new in GHC head.) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15702#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#15702: "-main-is" flag is broken for recent ghc-head -------------------------------------+------------------------------------- Reporter: terrorjack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.8.1 Component: Compiler | Version: 8.7 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Incorrect | (amd64) error/warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by adamgundry): * cc: adamgundry (added) * version: 8.6.1 => 8.7 * milestone: 8.6.1 => 8.8.1 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15702#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#15702: "-main-is" flag is broken for recent ghc-head -------------------------------------+------------------------------------- Reporter: terrorjack | Owner: (none) Type: bug | Status: patch Priority: normal | Milestone: 8.8.1 Component: Compiler | Version: 8.7 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Incorrect | (amd64) error/warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D5322 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Krzysztof Gogolewski ): In [changeset:"0e7790abf7d19d19f84c86dc95e50beb65462d12/ghc" 0e7790a/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="0e7790abf7d19d19f84c86dc95e50beb65462d12" Fix trac #15702, as a followon to fix for #13704. Summary: The effect of this change is that -main-is changes the default export list for the main module, but does not apply the same change to non-main modules. This fixes some cases where -main-is was used to wrap a module that expected that default behavior (exporting `main`, even when that wasn't the main entry point name). Reviewers: mpickering, monoidal, bgamari Subscribers: rwbarton, carter GHC Trac Issues: #13704, #15702 Differential Revision: https://phabricator.haskell.org/D5322 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15702#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler