blob: c6d33fcaecab7b07766c54092759e57fc14b239e (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
|
package dotty.tools.dotc
package transform
import core._
import TreeTransforms._
import Contexts.Context
import Flags._
import SymUtils._
import Symbols._
import SymDenotations._
import Types._
import Decorators._
import DenotTransformers._
import StdNames._
import NameOps._
import ast.Trees._
import dotty.tools.dotc.ast.tpd
import dotty.tools.dotc.core.Constants.Constant
import util.Positions._
import Names._
import collection.mutable
/** This phase replaces calls to DottyPredef.classTag by code that synthesizes appropriate ClassTag
*/
class ClassTags extends MiniPhaseTransform with IdentityDenotTransformer { thisTransform =>
import ast.tpd._
private var classTagCache: Symbol = null
private var typeTagCache: Symbol = null
private var scala2ClassTagModule: Symbol = null
override def prepareForUnit(tree: tpd.Tree)(implicit ctx: Context): TreeTransform = {
classTagCache = defn.DottyPredefModule.requiredMethod(nme.classTag)
typeTagCache = defn.DottyPredefModule.requiredMethod(nme.typeTag)
scala2ClassTagModule = ctx.requiredModule("scala.reflect.ClassTag")
this
}
override def phaseName: String = "classTags"
override def transformTypeApply(tree: tpd.TypeApply)(implicit ctx: Context, info: TransformerInfo): tpd.Tree =
if (tree.fun.symbol eq classTagCache) {
val tp = tree.args.head.tpe
val defn = ctx.definitions
val (elemType, ndims) = tp match {
case defn.MultiArrayType(elem, ndims) => (elem, ndims)
case _ => (tp, 0)
}
val claz = tp.classSymbol
val elemClaz = elemType.classSymbol
assert(!claz.isPrimitiveValueClass) // should be inserted by typer
val elemTag = if (defn.ScalaValueClasses.contains(elemClaz) || elemClaz == defn.NothingClass || elemClaz == defn.NullClass)
ref(defn.DottyPredefModule).select(s"${elemClaz.name}ClassTag".toTermName)
else if (ValueClasses.isDerivedValueClass(elemClaz)) ref(claz.companionModule)
else if (elemClaz eq defn.AnyClass) ref(scala2ClassTagModule).select(nme.Any)
else {
val erazedTp = TypeErasure.erasure(elemType).classSymbol.typeRef
ref(scala2ClassTagModule).select(nme.apply).appliedToType(erazedTp).appliedTo(Literal(Constant(erazedTp)))
}
(1 to ndims).foldLeft(elemTag)((arr, level) => Select(arr, nme.wrap).ensureApplied).ensureConforms(tree.tpe)
} else tree
}
|
