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
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
|
package dotty.tools.dotc.core
import Contexts._, Types._, Symbols._, Names._, Flags._, Scopes._
trait TypeOps { this: Context =>
def newSkolemSingleton(underlying: Type) = TermRef.withSym(NoPrefix, newSkolem(underlying))
final def asSeenFrom(tp: Type, pre: Type, cls: Symbol, theMap: AsSeenFromMap): Type = {
def toPrefix(pre: Type, cls: Symbol, thiscls: ClassSymbol): Type = ctx.debugTraceIndented(s"toPrefix($pre, $cls, $thiscls)") {
if ((pre eq NoType) || (pre eq NoPrefix) || (cls is PackageClass))
tp
else if (thiscls.derivesFrom(cls) && pre.baseType(thiscls).exists)
pre match {
case SuperType(thispre, _) => thispre
case _ => pre
}
else
toPrefix(pre.baseType(cls).normalizedPrefix, cls.owner, thiscls)
}
ctx.debugTraceIndented(s"$tp.asSeenFrom($pre, $cls)") { // !!! DEBUG
tp match {
case tp: NamedType =>
val sym = tp.symbol
if (sym.isStatic) tp
else {
val tp1 = tp.derivedNamedType(asSeenFrom(tp.prefix, pre, cls, theMap))
// Here's an explanation why we short-circuit instantiated type parameters.
// Say you have This is translated to:
//
// class List[type T] ==> class List { type T; val hd: T }
// xs: List[Int] ==> List { type T = Int }
//
// Then with the line above, xs.hd would have type xs.T
//
// But in Scala 2.x, its type is Int, which is the dealiased version
// of xs.T. With the logic below, we get the same outcome as for 2.x.
if ((tp1 ne tp) && (sym is (TypeParam, butNot = Deferred))) tp1.dealias
else tp1
}
case ThisType(thiscls) =>
toPrefix(pre, cls, thiscls)
case _: BoundType | NoPrefix =>
tp
case tp: RefinedType =>
tp.derivedRefinedType(
asSeenFrom(tp.parent, pre, cls, theMap),
tp.refinedName,
asSeenFrom(tp.refinedInfo, pre, cls, theMap))
// case tp: ClassInfo => !!! disabled for now
// tp.derivedClassInfo(asSeenFrom(tp.prefix, pre, cls, theMap))
case _ =>
(if (theMap != null) theMap else new AsSeenFromMap(pre, cls))
.mapOver(tp)
}
}
}
class AsSeenFromMap(pre: Type, cls: Symbol) extends TypeMap {
def apply(tp: Type) = asSeenFrom(tp, pre, cls, this)
}
final def isVolatile(tp: Type): Boolean = {
/** Pre-filter to avoid expensive DNF computation */
def needsChecking(tp: Type, isPart: Boolean): Boolean = tp match {
case tp: TypeRef =>
tp.info match {
case TypeBounds(lo, hi) =>
if (lo eq hi) needsChecking(hi, isPart)
else isPart || tp.controlled(isVolatile(hi))
case _ => false
}
case tp: RefinedType =>
needsChecking(tp.parent, true)
case tp: TypeProxy =>
needsChecking(tp.underlying, isPart)
case AndType(l, r) =>
needsChecking(l, true) || needsChecking(r, true)
case OrType(l, r) =>
isPart || needsChecking(l, isPart) && needsChecking(r, isPart)
case _ =>
false
}
needsChecking(tp, false) && {
tp.DNF forall { case (parents, refinedNames) =>
val absParents = parents filter (_.symbol is Deferred)
absParents.size >= 2 || {
val ap = absParents.head
(parents exists (p =>
(p ne ap) || p.abstractMemberNames(tp).nonEmpty)) ||
(refinedNames & tp.abstractMemberNames()).nonEmpty ||
isVolatile(ap)
}
}
}
}
/** Normalize a list of parent types of class `cls` that may contain refinements
* to a list of typerefs, by converting all refinements to member
* definitions in scope `decls`. Can add members to `decls` as a side-effect.
*/
def normalizeToRefs(parents: List[Type], cls: ClassSymbol, decls: Scope): List[TypeRef] = {
// println(s"normalizing $parents of $cls in ${cls.owner}") // !!! DEBUG
var refinements = Map[TypeName, Type]()
var formals = Map[TypeName, Symbol]()
def normalizeToRef(tp: Type): TypeRef = tp match {
case tp @ RefinedType(tp1, name: TypeName) =>
refinements = refinements.updated(name,
refinements get name match {
case Some(info) => info & tp.refinedInfo
case none => tp.refinedInfo
})
formals = formals.updated(name, tp1.typeParamNamed(name))
normalizeToRef(tp1)
case tp: TypeRef =>
tp
case ErrorType =>
defn.AnyClass.typeConstructor
case _ =>
throw new TypeError(s"unexpected parent type: $tp")
}
val parentRefs = parents map normalizeToRef
for ((name, tpe) <- refinements) {
val formal = formals(name)
val bounds = tpe //.toRHS(formal)
assert(decls.lookup(name) == NoSymbol, // DEBUG
s"redefinition of ${decls.lookup(name).debugString} in ${cls.showLocated}")
val sym = ctx.newSymbol(cls, name, formal.flags & RetainedTypeArgFlags, bounds)
cls.enter(sym, decls)
}
parentRefs
}
}
|
