Yes this is annoying.
The thing is that with the first constructor only we'd get
(LHsSigWcType Id)
after type checking, but we don't have such a thing. `HsTypes` are typechecked
to `Types`.
Perhaps we could have
(LHsSigWcType (StopAtRenamer d))
where
type family StopAtRenamer a where
StopAtRenamer Id = Name
StopAtRenamer x = x
If this pattern happened a lot it might be worth it. But I think this is the
only occurrence.
Better ideas welcome.
Simon
| -----Original Message-----
| From: ghc-devs [mailto:[email protected]] On Behalf Of Alan
| & Kim Zimmerman
| Sent: 19 December 2015 13:15
| To: [email protected]
| Subject: ExprWithTySigOut
|
| At the moment HsExpr includes the following two constructors
|
| | ExprWithTySig
| (LHsExpr id)
| (LHsSigWcType id)
|
| | ExprWithTySigOut -- Post typechecking
| (LHsExpr id)
| (LHsSigWcType Name) -- Retain the signature,
| -- as HsSigType Name, for
| -- round-tripping purposes
|
| I do not understand why we need the second one, which hard-codes Name
| instead of id.
|
| There are a couple of places where there is an XXXOut variant with
| hard coded Name parameter, and these complicate creating any kind of
| custom class intended to work on a parameterised AST as it ripples out
| and forces Name instances of it everywhere.
|
| Perhaps we should introduce HsExprLR id id to cope with renaming?
|
| Alan
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