[commit: ghc] master: Refactor coercion holes (a492af0)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/a492af06d3264530d134584f22ffb726a16c78ec/ghc

>---------------------------------------------------------------

commit a492af06d3264530d134584f22ffb726a16c78ec
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Thu Dec 21 13:31:13 2017 +0000

    Refactor coercion holes
    
    In fixing Trac #14584 I found that it would be /much/ more
    convenient if a "hole" in a coercion (much like a unification
    variable in a type) acutally had a CoVar associated with it
    rather than just a Unique.  Then I can ask what the free variables
    of a coercion is, and get a set of CoVars including those
    as-yet-un-filled in holes.
    
    Once that is done, it makes no sense to stuff coercion holes
    inside UnivCo.  They were there before so we could know the
    kind and role of a "hole" coercion, but once there is a CoVar
    we can get that info from the CoVar.  So I removed HoleProv
    from UnivCoProvenance and added HoleCo to Coercion.
    
    In summary:
    
    * Add HoleCo to Coercion and remove HoleProv from UnivCoProvanance
    
    * Similarly in IfaceCoercion
    
    * Make CoercionHole have a CoVar in it, not a Unique
    
    * Make tyCoVarsOfCo return the free coercion-hole variables
      as well as the ordinary free CoVars.  Similarly, remember
      to zonk the CoVar in a CoercionHole
    
    We could go further, and remove CoercionHole as a distinct type
    altogther, just collapsing it into HoleCo.  But I have not done
    that yet.


>---------------------------------------------------------------

a492af06d3264530d134584f22ffb726a16c78ec
 compiler/backpack/RnModIface.hs   |  1 +
 compiler/coreSyn/CoreFVs.hs       |  2 +-
 compiler/coreSyn/CoreLint.hs      |  7 +++-
 compiler/iface/IfaceSyn.hs        |  5 +--
 compiler/iface/IfaceType.hs       | 56 ++++++++++++--------------
 compiler/iface/TcIface.hs         |  5 +--
 compiler/iface/ToIface.hs         |  5 ++-
 compiler/typecheck/TcCanonical.hs |  2 +-
 compiler/typecheck/TcEnv.hs       | 16 +++++---
 compiler/typecheck/TcErrors.hs    |  6 +--
 compiler/typecheck/TcHsSyn.hs     | 30 ++++++--------
 compiler/typecheck/TcInteract.hs  |  6 +--
 compiler/typecheck/TcMType.hs     | 75 +++++++++++++++++++---------------
 compiler/typecheck/TcPluginM.hs   |  4 +-
 compiler/typecheck/TcRnTypes.hs   | 25 +++++++-----
 compiler/typecheck/TcSMonad.hs    |  4 +-
 compiler/typecheck/TcTyDecls.hs   |  2 +-
 compiler/typecheck/TcType.hs      | 14 +++----
 compiler/typecheck/TcUnify.hs     | 19 +++++----
 compiler/typecheck/TcValidity.hs  |  4 +-
 compiler/types/Coercion.hs        | 42 +++++++++-----------
 compiler/types/FamInstEnv.hs      |  2 +-
 compiler/types/OptCoercion.hs     |  7 ++--
 compiler/types/TyCoRep.hs         | 84 +++++++++++++++++++++++----------------
 compiler/types/Type.hs            | 19 +++++----
 25 files changed, 234 insertions(+), 208 deletions(-)

Diff suppressed because of size. To see it, use:

    git diff-tree --root --patch-with-stat --no-color --find-copies-harder --ignore-space-at-eol --cc a492af06d3264530d134584f22ffb726a16c78ec