#14678: GHc 8.4.1-alpha's bundled transformers doesn't correspond to a tagged release -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.4.1 Component: Compiler | Version: 8.4.1-alpha1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- GHC 8.4.1-alpha claims to be bundled with `transformers-0.5.4.0`, but this isn't true. That's because it's using `transformers` commit http://git.haskell.org/packages/transformers.git/commit/36311d39bc545261dab8..., which happened somewhere in between the `0.5.4.0` and `0.5.5.0` releases. This is actually a problem for me in practice because that commit gives a `Semigroup` instance for `Constant` which should have only been introduced in `0.5.5.0`, according to the [https://hackage.haskell.org/package/transformers-0.5.5.0/changelog changelog]. But commit 36311d39bc545261dab85d4a27af562db1868ed6 uses version `0.5.4.0`, which makes it impossible to guard against the existence of this instance using CPP (see [https://travis-ci.org/ekmett /transformers-compat/jobs/329285046#L739 this Travis build failure] for an example of this problem occurring). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14678 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler