Scala path dependent return type from parameter
- by Rich Oliver
In the following code using 2.10.0M3 in Eclipse plugin 2.1.0 for 2.10M3. I'm using the default setting which is targeting JVM 1.5
class GeomBase[T <: DTypes] {
abstract class NewObjs {
def newHex(gridR: GridBase, coodI: Cood): gridR.HexRT
}
class GridBase {
selfGrid =>
type HexRT = HexG with T#HexTr
def uniformRect (init: NewObjs) {
val hexCood = Cood(2 ,2)
val hex: HexRT = init.newHex(selfGrid, hexCood)// won't compile
}
}
}
Error message:
Description Resource Path Location Type type mismatch;
found: GeomBase.this.GridBase#HexG with T#HexTr
required: GridBase.this.HexRT (which expands to) GridBase.this.HexG with T#HexTr GeomBase.scala
Why does the compiler think the method returns the type projection GridBase#HexG when it should be this specific instance of GridBase?
Edit transferred to a simpler code class in responce to comments now getting a different error message.
package rStrat
class TestClass {
abstract class NewObjs {
def newHex(gridR: GridBase): gridR.HexG
}
class GridBase {
selfGrid =>
def uniformRect (init: NewObjs) {
val hex: HexG = init.newHex(this) //error here
}
class HexG {
val test12 = 5
}
}
}
.
Error line 11:Description Resource Path Location Type
type mismatch; found : gridR.HexG required: GridBase.this.HexG
possible cause: missing arguments for method or constructor TestClass.scala /SStrat/src/rStrat line 11 Scala Problem
Update I've switched to 2.10.0M4 and updated the plug-in to the M4 version on a fresh version of Eclipse and switched to JVM 1.6 (and 1.7) but the problems are unchanged.
