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| author | Adam Gundry <adam@well-typed.com> | 2017-02-14 09:53:28 -0500 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2017-02-14 10:53:01 -0500 |
| commit | da493897ac6ee2b17a0c58b51315f9d136de730d (patch) | |
| tree | 08e13ee790290eada30f1ff1c7d1a2cae9f9d69b /compiler/hsSyn/HsExpr.hs | |
| parent | c3bbd1afc85cd634d8d26e27bafb92cc7481667b (diff) | |
| download | haskell-da493897ac6ee2b17a0c58b51315f9d136de730d.tar.gz | |
Implement HasField constraint solving and modify OverloadedLabels
This implements automatic constraint solving for the new HasField class
and modifies the existing OverloadedLabels extension, as described in
the GHC proposal
(https://github.com/ghc-proposals/ghc-proposals/pull/6). Per the current
form of the proposal, it does *not* currently introduce a separate
`OverloadedRecordFields` extension.
This replaces D1687.
The users guide documentation still needs to be written, but I'll do
that after the implementation is merged, in case there are further
design changes.
Test Plan: new and modified tests in overloadedrecflds
Reviewers: simonpj, goldfire, dfeuer, bgamari, austin, hvr
Reviewed By: bgamari
Subscribers: maninalift, dfeuer, ysangkok, thomie, mpickering
Differential Revision: https://phabricator.haskell.org/D2708
Diffstat (limited to 'compiler/hsSyn/HsExpr.hs')
| -rw-r--r-- | compiler/hsSyn/HsExpr.hs | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/compiler/hsSyn/HsExpr.hs b/compiler/hsSyn/HsExpr.hs index 7202452852..9ad096e6d7 100644 --- a/compiler/hsSyn/HsExpr.hs +++ b/compiler/hsSyn/HsExpr.hs @@ -292,9 +292,11 @@ data HsExpr id | HsRecFld (AmbiguousFieldOcc id) -- ^ Variable pointing to record selector -- Not in use after typechecking - | HsOverLabel FastString -- ^ Overloaded label (See Note [Overloaded labels] - -- in GHC.OverloadedLabels) - -- NB: Not in use after typechecking + | HsOverLabel (Maybe id) FastString + -- ^ Overloaded label (Note [Overloaded labels] in GHC.OverloadedLabels) + -- @Just id@ means @RebindableSyntax@ is in use, and gives the id of the + -- in-scope 'fromLabel'. + -- NB: Not in use after typechecking | HsIPVar HsIPName -- ^ Implicit parameter (not in use after typechecking) | HsOverLit (HsOverLit id) -- ^ Overloaded literals @@ -824,7 +826,7 @@ ppr_expr (HsVar (L _ v)) = pprPrefixOcc v ppr_expr (HsUnboundVar uv)= pprPrefixOcc (unboundVarOcc uv) ppr_expr (HsConLikeOut c) = pprPrefixOcc c ppr_expr (HsIPVar v) = ppr v -ppr_expr (HsOverLabel l) = char '#' <> ppr l +ppr_expr (HsOverLabel _ l)= char '#' <> ppr l ppr_expr (HsLit lit) = ppr lit ppr_expr (HsOverLit lit) = ppr lit ppr_expr (HsPar e) = parens (ppr_lexpr e) |