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author | Martin Odersky <odersky@gmail.com> | 2014-03-10 22:42:39 +0100 |
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committer | Tobias Schlatter <tobias@meisch.ch> | 2014-03-20 20:25:05 +0100 |
commit | 5b687fbee23060fbed285f090e3592f2b8cb6beb (patch) | |
tree | 85b63c2f90e813db42adb3b327f542e389640b20 /src/dotty/tools/dotc/ast/Desugar.scala | |
parent | 3ba0931636a5d34ca2da9588f2952af709d41ace (diff) | |
download | dotty-5b687fbee23060fbed285f090e3592f2b8cb6beb.tar.gz dotty-5b687fbee23060fbed285f090e3592f2b8cb6beb.tar.bz2 dotty-5b687fbee23060fbed285f090e3592f2b8cb6beb.zip |
Generalize derived type tree scheme.
To get truly hygienic desugared trees, we need a derived type tree scheme that's more
flexible than just the previous two choices of info-of-symbol and typeref-of-symbol.
The new scheme based on DerivedTypeTrees allows arbitrary methods to derive the type tree's type.
Diffstat (limited to 'src/dotty/tools/dotc/ast/Desugar.scala')
-rw-r--r-- | src/dotty/tools/dotc/ast/Desugar.scala | 32 |
1 files changed, 13 insertions, 19 deletions
diff --git a/src/dotty/tools/dotc/ast/Desugar.scala b/src/dotty/tools/dotc/ast/Desugar.scala index e8099f360..4a635d259 100644 --- a/src/dotty/tools/dotc/ast/Desugar.scala +++ b/src/dotty/tools/dotc/ast/Desugar.scala @@ -24,16 +24,6 @@ object desugar { // ----- TypeTrees that refer to other tree's symbols ------------------- - /** A marker tree used as the original for TypeTrees that get their type by taking - * the typeRef of some other tree's symbol. (currently unused) - */ - val TypeRefOfSym = new TypeTree(EmptyTree) - - /** A marker tree used as the original for TypeTrees that get their type by taking - * the result type of the info of some other tree's symbol. - */ - val InfoOfSym = new TypeTree(EmptyTree) - /** Attachment key containing TypeTrees whose type is computed * from the symbol in this type. These type trees have marker trees * TypeRefOfSym or InfoOfSym as their originals. @@ -46,15 +36,19 @@ object desugar { */ val OriginalSymbol = new Attachment.Key[Symbol] - /** A type tree that is marked to get its type by taking - * the typeRef of some other tree's symbol. Enters the type tree - * in the References attachment of the `original` tree as a side effect. + /** A type tree that gets its type from some other tree's symbol. Enters the + * type tree in the References attachment of the `from` tree as a side effect. */ - def refTypeTree(original: Tree, marker: TypeTree): TypeTree = { - val result = TypeTree(marker) - val existing = original.attachmentOrElse(References, Nil) - original.putAttachment(References, result :: existing) - result + abstract class DerivedTypeTree(from: Tree) extends TypeTree(EmptyTree) { + val existing = from.attachmentOrElse(References, Nil) + from.putAttachment(References, this :: existing) + + /** The method that computes the type of this tree */ + def derivedType(originalSym: Symbol)(implicit ctx: Context): Type + } + + class SetterParam(vdef: ValDef) extends DerivedTypeTree(vdef) { + def derivedType(vsym: Symbol)(implicit ctx: Context) = vsym.info.resultType } // ----- Desugar methods ------------------------------------------------- @@ -73,7 +67,7 @@ object desugar { // val getter = ValDef(mods, name, tpt, rhs) withPos vdef.pos ? // right now vdef maps via expandedTree to a thicket which concerns itself. // I don't see a problem with that but if there is one we can avoid it by making a copy here. - val setterParam = makeSyntheticParameter(tpt = refTypeTree(vdef, InfoOfSym)) + val setterParam = makeSyntheticParameter(tpt = new SetterParam(vdef)) val setterRhs = if (vdef.rhs.isEmpty) EmptyTree else unitLiteral val setter = cpy.DefDef(vdef, mods | Accessor, name.setterName, Nil, (setterParam :: Nil) :: Nil, |