Place staged type captures in Quote AST #17424
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| // `quoted.Type.of[<body>](<quotes>)` --> `'[<body1>].apply(<quotes>)` | ||
| val quotes = transform(tree.args.head) | ||
| val TypeApply(fun, _) = tree.fun: @unchecked | ||
| if level != 0 then cpy.Apply(tree)(cpy.TypeApply(tree.fun)(fun, body1 :: Nil), quotes :: Nil) |
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I was confused when I first read this code, because tags isn't used in this branch, I had to go read transformQuoteBody to realize that when level != 0 then tags is always Nil. Maybe, adding a comment mentioning this would be enough.
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I inlined transformQuoteBody and refactored the code to only make this transformation at level == 0. Other levels are transformed using super.transform.
| case Nil => transformedBody | ||
| case tags => tpd.Block(tags, transformedBody).withSpan(body.span) | ||
| } | ||
| private def transformQuoteBody(body: Tree, span: Span)(using Context): (List[Tree], Tree) = |
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The parameter span isn't used anymore.
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I inlined transformQuoteBody.
| } | ||
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| /** Remove references to local types that will not be defined in this quote */ | ||
| private def getTypeHoleType(using Context) = new TypeMap() { |
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Looks like this code already existed before but FWIW, I think TypeOps.AvoidMap would be better suited here (or its superclass ApproximatingTypeMap if more flexibility is needed), just using TypeMap doesn't take variance and bounds into account.
It would not make sense to pickle the tags as they are represented in |
| mapOver(tp) | ||
| private def getTermHoleType(using Context) = new AvoidMap { | ||
| def toAvoid(tp: NamedType): Boolean = | ||
| tp.prefix == NoPrefix // reference to terms and type defined in outer quote |
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What about references defined in the quote itself, e.g.:
'{ class A; val x: A = new A; ... }they have NoPrefix as a prefix, but they're not defined in an outer quote.
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I will probably need to move this into the Splicing phase where we know the set of definitions that are in the outer quote. I will open a separate PR. Should I revert that change in this PR? As far as I can see we are already avoiding those references.
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R. Should I revert that change in this PR?
Sure!
This change makes it easier to handle instances
Type[T]that are inserted into a level 0 quote. These used to be encoded in the staging phase as type aliases@TypeSplice type A = t.Underlying. This makes it hard to debug and check invariants. Instead, we can collect the list of type tags needed and store them in the quote. At the same time, we can convert references to those types intot.Underlying. We can generate the@TypeSplice type A = t.Underlyingjust before pickling and replace all references tot.UnderlyingwithAat that point.This is only an internal representation change while transforming the quote. It will not affect TASTy.