Runtime crash: incorrect inline match resolution for intersection types with opaque types

[jchyb]

Compiler version

any

Minimized code

object Test:
  opaque type ExtraString = String
  opaque type NumString <: ExtraString = String
  opaque type OtherString <: ExtraString = String

  def makeExtraString(): String & ExtraString = "not a number"

  extension (t: NumString)
    def number: Double =
      (t : String).toDouble

  extension [T1 <: ExtraString](inline a: T1)
    inline def test: ExtraString =
      inline a match
        case x: NumString =>
          println(x.number) // runtime crash stack trace points here
          x
        case x: ExtraString =>
          println("expected behavior")
          x
    end test

end Test

import Test.*

@main def main() =
  val m1: String & ExtraString = makeExtraString()
  m1.test

Output

runtime output:

Exception in thread "main" java.lang.NumberFormatException: For input string: "not a number"
        at java.base/jdk.internal.math.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:2054)
        at java.base/jdk.internal.math.FloatingDecimal.parseDouble(FloatingDecimal.java:110)
        at java.base/java.lang.Double.parseDouble(Double.java:651)
        at scala.collection.StringOps$.toDouble$extension(StringOps.scala:951)
        at Test$.number(X2.scala:11)
        at X2$package$.main(X2.scala:17)
        at main.main(X2.scala:28)

Expectation

Print out "expected behavior"

[sjrd]

You're on the scope of the opaque type aliases. So they're all aliases of String. I see no bug here.

[jchyb]

This is true. I got too lost in the details while working on #13461. Closing this.