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Don't zip AppliedTypeVar params and typeArgs 

Avoid unnecessary allocations.
This commit is contained in:
Georgi Krastev 2018-12-31 01:55:06 +02:00
parent d46849d2b7
commit 1068769507
1 changed files with 8 additions and 14 deletions
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22
src/reflect/scala/reflect/internal/Types.scala
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@ -3276,8 +3276,8 @@ trait Types
else new TypeVar(origin, constr) {}
}
else if (args.size == params.size) {
if (untouchable) new AppliedTypeVar(origin, constr, params zip args) with UntouchableTypeVar
else new AppliedTypeVar(origin, constr, params zip args)
if (untouchable) new AppliedTypeVar(origin, constr, params, args) with UntouchableTypeVar
else new AppliedTypeVar(origin, constr, params, args)
}
else if (args.isEmpty) {
if (untouchable) new HKTypeVar(origin, constr, params) with UntouchableTypeVar
@ -3313,23 +3313,17 @@ trait Types
override def isHigherKinded = true
}
/** Precondition: zipped params/args nonEmpty. (Size equivalence enforced structurally.)
*/
/** Precondition: `params.length == typeArgs.length > 0` (enforced structurally). */
class AppliedTypeVar(
_origin: Type,
_constr: TypeConstraint,
zippedArgs: List[(Symbol, Type)]
override val params: List[Symbol],
override val typeArgs: List[Type]
) extends TypeVar(_origin, _constr) {
require(zippedArgs.nonEmpty, this)
override def params: List[Symbol] = zippedArgs map (_._1)
override def typeArgs: List[Type] = zippedArgs map (_._2)
require(params.nonEmpty && sameLength(params, typeArgs), this)
override def safeToString: String = super.safeToString + typeArgs.map(_.safeToString).mkString("[", ", ", "]")
override def setInst(tp: Type): this.type = super.setInst {
val instArgs = tp.typeArgs
if (sameLength(zippedArgs, instArgs) && forall3(params, typeArgs, instArgs) { (param, targ, inst) =>
param.isCovariant && targ <:< inst || param.isContravariant && inst <:< targ || targ =:= inst
}) tp.typeConstructor else NoType
}
override def setInst(tp: Type): this.type =
super.setInst(if (isSubArgs(typeArgs, tp.typeArgs, params, Depth.AnyDepth)) tp.typeConstructor else NoType)
}
trait UntouchableTypeVar extends TypeVar {