[commit: ghc] wip/spj-tc-branch: A collection of type-inference refactorings. (f477756)

git at git.haskell.org git at git.haskell.org
Tue Sep 20 20:48:32 UTC 2016


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

On branch  : wip/spj-tc-branch
Link       : http://ghc.haskell.org/trac/ghc/changeset/f477756baefc1b16549631efa0de56ccbb66bdef/ghc

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

commit f477756baefc1b16549631efa0de56ccbb66bdef
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Tue Aug 30 11:00:47 2016 +0100

    A collection of type-inference refactorings.
    
    1. Modify TcType.ExpType to make a distinct data type,
       InferResult for the Infer case, and consequential
       refactoring.
    
    2. Define a new function TcUnify.fillInferResult, to fill in
       an InferResult. It uses TcMType.promoteTcType to promote
       the type to the level of the InferResult.
       See TcMType Note [Promoting a type]
       This refactoring is in preparation for an improvement
       to typechecking pattern bindings, coming next.
    
       I flirted with an elaborate scheme to give better
       higher rank inference, but it was just too complicated.
       See TcMType Note [Promotion and higher rank types]
    
    3. Add to InferResult a new field ir_inst :: Bool to say
       whether or not the type used to fill in the
       InferResult should be deeply instantiated.  See
       TcUnify Note [Deep instantiation of InferResult].
    
    4. Add a TcLevel to SkolemTvs. This will be useful generally
    
        - it's a fast way to see if the type
          variable escapes when floating (not used yet)
    
        - it provides a good consistency check when updating a
          unification variable (TcMType.writeMetaTyVarRef, the
          level_check_ok check)
    
       I originally had another reason (related to the flirting
       in (2), but I left it in because it seems like a step in
       the right direction.
    
    5. Reduce and simplify the plethora of uExpType,
       tcSubType and related functions in TcUnify.  It was
       such an opaque mess and it's still not great, but it's
       better.
    
    6. Simplify the uo_expected field of TypeEqOrigin.  Richard
       had generatlised it to a ExpType, but it was almost always
       a Check type.  Now it's back to being a plain TcType which
       is much easier.
    
    7. Improve error messages by refraining from skolemisation when
       it's clear that there's an error: see
       TcUnify Note [Don't skolemise unnecessarily]
    
    8. Type.isPiTy and isForAllTy seem to be missing a coreView check,
       so I added it
    
    All these changes led to quite bit of error message wibbling


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

f477756baefc1b16549631efa0de56ccbb66bdef
 compiler/ghci/RtClosureInspect.hs                  |   2 +-
 compiler/typecheck/Inst.hs                         |   4 +-
 compiler/typecheck/TcBinds.hs                      |  68 +---
 compiler/typecheck/TcErrors.hs                     |   6 +-
 compiler/typecheck/TcExpr.hs                       |  24 +-
 compiler/typecheck/TcHsSyn.hs                      |   2 +-
 compiler/typecheck/TcHsType.hs                     |  21 +-
 compiler/typecheck/TcInstDcls.hs                   |   3 +-
 compiler/typecheck/TcMType.hs                      | 324 +++++++++++-----
 compiler/typecheck/TcMatches.hs                    |  19 +-
 compiler/typecheck/TcPat.hs                        |  34 +-
 compiler/typecheck/TcPatSyn.hs                     |  16 +-
 compiler/typecheck/TcRnTypes.hs                    |   2 +-
 compiler/typecheck/TcType.hs                       |  75 ++--
 compiler/typecheck/TcUnify.hs                      | 407 +++++++++++----------
 compiler/typecheck/TcValidity.hs                   |   2 +-
 compiler/types/Type.hs                             |   2 +
 compiler/vectorise/Vectorise/Generic/PData.hs      |   2 +-
 testsuite/tests/ado/ado004.stderr                  |   4 +-
 .../tests/annotations/should_fail/annfail10.stderr |  12 +-
 testsuite/tests/driver/T2182.stderr                |  32 +-
 testsuite/tests/gadt/gadt-escape1.stderr           |  16 +-
 testsuite/tests/gadt/gadt13.stderr                 |  10 +-
 testsuite/tests/gadt/gadt7.stderr                  |  18 +-
 .../tests/ghci.debugger/scripts/break012.stdout    |   8 +-
 .../tests/ghci.debugger/scripts/print022.stdout    |   4 +-
 testsuite/tests/ghci/scripts/T11524a.stdout        |   4 +-
 testsuite/tests/ghci/scripts/T2182ghci.stderr      |  10 +-
 .../tests/indexed-types/should_fail/T12386.hs      |   9 +
 .../tests/indexed-types/should_fail/T12386.stderr  |   7 +
 .../tests/indexed-types/should_fail/T7354.stderr   |   8 +-
 .../tests/parser/should_compile/read014.stderr     |   2 +-
 testsuite/tests/parser/should_fail/T7848.stderr    |   3 -
 .../tests/parser/should_fail/readFail003.stderr    |   4 +-
 .../partial-sigs/should_compile/T10438.stderr      |  14 +-
 .../tests/patsyn/should_compile/T11213.stderr      |   2 +-
 testsuite/tests/patsyn/should_fail/mono.stderr     |   4 +-
 testsuite/tests/perf/compiler/stdout               |  29 ++
 testsuite/tests/polykinds/T7438.stderr             |  16 +-
 testsuite/tests/rebindable/rebindable6.stderr      |  12 +-
 testsuite/tests/roles/should_compile/T8958.stderr  |   5 +-
 testsuite/tests/th/T11452.stderr                   |   2 +-
 testsuite/tests/th/T2222.stderr                    |   2 +-
 .../typecheck/should_compile/ExPatFail.stderr      |   4 +-
 .../should_compile/T12427.stderr}                  |   0
 .../tests/typecheck/should_compile/T12427a.stderr  |  33 ++
 .../tests/typecheck/should_compile/tc141.stderr    |   6 +-
 .../tests/typecheck/should_fail/T10495.stderr      |  10 +-
 .../tests/typecheck/should_fail/T10619.stderr      |  18 +-
 .../tests/typecheck/should_fail/T12177.stderr      |  19 +-
 testsuite/tests/typecheck/should_fail/T3102.hs     |   6 +-
 testsuite/tests/typecheck/should_fail/T3102.stderr |  12 -
 testsuite/tests/typecheck/should_fail/T7453.stderr |  50 +--
 testsuite/tests/typecheck/should_fail/T7734.stderr |  12 +-
 testsuite/tests/typecheck/should_fail/T8428.stderr |   5 +-
 testsuite/tests/typecheck/should_fail/T9109.stderr |  10 +-
 testsuite/tests/typecheck/should_fail/T9318.stderr |  12 +-
 .../tests/typecheck/should_fail/VtaFail.stderr     |   2 +-
 testsuite/tests/typecheck/should_fail/all.T        |   2 +-
 .../tests/typecheck/should_fail/tcfail002.stderr   |   6 +-
 .../tests/typecheck/should_fail/tcfail004.stderr   |   6 +-
 .../tests/typecheck/should_fail/tcfail005.stderr   |   6 +-
 .../tests/typecheck/should_fail/tcfail013.stderr   |   2 +-
 .../tests/typecheck/should_fail/tcfail014.stderr   |   6 +-
 .../tests/typecheck/should_fail/tcfail018.stderr   |   2 +-
 .../tests/typecheck/should_fail/tcfail032.stderr   |   6 +-
 .../tests/typecheck/should_fail/tcfail099.stderr   |   6 +-
 .../tests/typecheck/should_fail/tcfail104.stderr   |  10 +-
 .../tests/typecheck/should_fail/tcfail140.stderr   |   4 +-
 .../tests/typecheck/should_fail/tcfail181.stderr   |   2 +-
 70 files changed, 848 insertions(+), 659 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 f477756baefc1b16549631efa0de56ccbb66bdef


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