diff options
Diffstat (limited to 'compiler/typecheck/TcRnTypes.hs')
| -rw-r--r-- | compiler/typecheck/TcRnTypes.hs | 33 |
1 files changed, 23 insertions, 10 deletions
diff --git a/compiler/typecheck/TcRnTypes.hs b/compiler/typecheck/TcRnTypes.hs index 1f06ae31cb..31624a8b9e 100644 --- a/compiler/typecheck/TcRnTypes.hs +++ b/compiler/typecheck/TcRnTypes.hs @@ -53,7 +53,7 @@ module TcRnTypes( isEmptyCts, isCTyEqCan, isCFunEqCan, isCDictCan_Maybe, isCFunEqCan_maybe, isCIrredEvCan, isCNonCanonical, isWantedCt, isDerivedCt, - isGivenCt, isHoleCt, isTypedHoleCt, isPartialTypeSigCt, + isGivenCt, isHoleCt, isExprHoleCt, isTypeHoleCt, ctEvidence, ctLoc, ctPred, ctFlavour, ctEqRel, mkNonCanonical, mkNonCanonicalCt, ctEvPred, ctEvLoc, ctEvEqRel, @@ -1135,8 +1135,9 @@ data Ct cc_ev :: CtEvidence } - | CHoleCan { -- Treated as an "insoluble" constraint - -- See Note [Insoluble constraints] + | CHoleCan { -- See Note [Hole constraints] + -- Treated as an "insoluble" constraint + -- See Note [Insoluble constraints] cc_ev :: CtEvidence, cc_occ :: OccName, -- The name of this hole cc_hole :: HoleSort -- The sort of this hole (expr, type, ...) @@ -1147,6 +1148,18 @@ data HoleSort = ExprHole -- ^ A hole in an expression (TypedHoles) | TypeHole -- ^ A hole in a type (PartialTypeSignatures) {- +Note [Hole constraints] +~~~~~~~~~~~~~~~~~~~~~~~ +CHoleCan constraints are used for two kinds of holes, +distinguished by cc_hole: + + * For holes in expressions + e.g. f x = g _ x + + * For holes in type signatures + e.g. f :: _ -> _ + f x = [x,True] + Note [Kind orientation for CTyEqCan] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Given an equality (t:* ~ s:Open), we can't solve it by updating t:=s, @@ -1324,13 +1337,13 @@ isHoleCt:: Ct -> Bool isHoleCt (CHoleCan {}) = True isHoleCt _ = False -isTypedHoleCt :: Ct -> Bool -isTypedHoleCt (CHoleCan { cc_hole = ExprHole }) = True -isTypedHoleCt _ = False +isExprHoleCt :: Ct -> Bool +isExprHoleCt (CHoleCan { cc_hole = ExprHole }) = True +isExprHoleCt _ = False -isPartialTypeSigCt :: Ct -> Bool -isPartialTypeSigCt (CHoleCan { cc_hole = TypeHole }) = True -isPartialTypeSigCt _ = False +isTypeHoleCt :: Ct -> Bool +isTypeHoleCt (CHoleCan { cc_hole = TypeHole }) = True +isTypeHoleCt _ = False instance Outputable Ct where ppr ct = ppr (cc_ev ct) <+> parens (text ct_sort) @@ -1412,7 +1425,7 @@ insolubleWC :: WantedConstraints -> Bool -- True if there are any insoluble constraints in the wanted bag. Ignore -- constraints arising from PartialTypeSignatures to solve as much of the -- constraints as possible before reporting the holes. -insolubleWC wc = not (isEmptyBag (filterBag (not . isPartialTypeSigCt) +insolubleWC wc = not (isEmptyBag (filterBag (not . isTypeHoleCt) (wc_insol wc))) || anyBag ic_insol (wc_impl wc) |