1. 21 Mar, 2019 3 commits
    • Ömer Sinan Ağacan's avatar
      7b213b8d
    • Ryan Scott's avatar
      Reject nested predicates in impredicativity checking · 8d18a873
      Ryan Scott authored
      When GHC attempts to unify a metavariable with a type containing
      foralls, it will be rejected as an occurrence of impredicativity.
      GHC was /not/ extending the same treatment to predicate types, such
      as in the following (erroneous) example from #11514:
      
      ```haskell
      foo :: forall a. (Show a => a -> a) -> ()
      foo = undefined
      ```
      
      This will attempt to instantiate `undefined` at
      `(Show a => a -> a) -> ()`, which is impredicative. This patch
      catches impredicativity arising from predicates in this fashion.
      
      Since GHC is pickier about impredicative instantiations, some test
      cases needed to be updated to be updated so as not to fall afoul of
      the new validity check. (There were a surprising number of
      impredicative uses of `undefined`!) Moreover, the `T14828` test case
      now has slightly less informative types shown with `:print`. This is
      due to a a much deeper issue with the GHCi debugger (see #14828).
      
      Fixes #11514.
      8d18a873
    • Sebastian Graf's avatar
      Add a bench flavour to Hadrian · 646e3dc2
      Sebastian Graf authored
      646e3dc2
  2. 20 Mar, 2019 32 commits
  3. 18 Mar, 2019 4 commits
  4. 17 Mar, 2019 1 commit
    • Ben Gamari's avatar
      ghc-heap: Introduce closureSize · cb61371e
      Ben Gamari authored
      This function allows the user to compute the (non-transitive) size of a
      heap object in words. The "closure" in the name is admittedly confusing
      but we are stuck with this nomenclature at this point.
      cb61371e