Regression in inline matches, inline parameter gets proxied.

[rcano]

Compiler version

3.0.2-RC2

Minimized code

public class Constants {
  public static final int A = 0;
  public static final int B = 2;
  public static final int C = 3;
}

class broken {
  sealed trait Foo
  case object A extends Foo
  case object B extends Foo
  case object C extends Foo
  case object D extends Foo

  inline def foo(inline f: Foo) = inline f match {
    case _: A.type => "the letter a"
    case _: B.type => "the letter b"
    case _: C.type => "the letter c"
    case _: D.type => "the letter d"
  }

  inline def thingy(
    depthClampEnable: Boolean = false,
    rasterizerDiscardEnable: Boolean = false,
    polygonMode: Int = 0,
    cullMode: Int = 0,
    frontFace: Int = 0,
    depthBiasEnable: Boolean = false,
    depthBiasConstantFactor: Float = 0,
    depthBiasClamp: Float = 0,
    depthBiasSlopeFactor: Float = 0,
    lineWidth: Float = 0,
    inline f: Foo = A,
  ) = {
    foo(f)
  }

  thingy(polygonMode = Constants.A, cullMode = Constants.B, frontFace = Constants.C, lineWidth = 1.0f)
}

Output

cannot reduce inline match with
 scrutinee:  f$1 : (f$1 : broken.this.Foo @uncheckedVariance)
 patterns :  case this.A:this.A.type
             case this.B:this.B.type
             case this.C:this.C.type
             case this.D:this.D.type

Expectation

It should compile fine, as it did in prior versions

Note

To replicate this bug, several conditions have to be met (I couldn't reproduce it otherwise):

• the outer method has to have default parameters unspecified when called (if you specify them all then it works)
• at least one of the specified parameters must come from a java defined symbol. If you define the constants in scala or inline the values, then it works.

[smarter]

Could you minimize this example to not depend on lwjgl?

[rcano]

Could you minimize this example to not depend on lwjgl?

done

[nicolasstucki]

Minimized to

class Foo
class Bar extends Foo

inline def thingy(a: Int = 0, b: Int = 0, inline c: Foo = new Bar) = {
  inline c match {
    case _: Bar =>
  }
}

def x = 1

def test = thingy(b = x)