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Fix aliased type support in ImplicitRunInfo #17471

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Fix aliased type support in ImplicitRunInfo #17471

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c9c4281
Fix aliased type support in ImplicitRunInfo
andrzejressel May 11, 2023
027981e
Add test
andrzejressel May 11, 2023
ae4007e
Fix comment
andrzejressel May 11, 2023
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2 changes: 2 additions & 0 deletions compiler/src/dotty/tools/dotc/typer/Implicits.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -610,6 +610,8 @@ trait ImplicitRunInfo:
else
partSeen += t
t.dealias match
case dealias if t ne dealias =>
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I don't see any motivation for this code, and without it the change seems unsystematic. There is no wildApprox anywhere else in this function. Why introduce it here?

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I have no idea how to find a better way to put this check. The only thing I've discovered is that this type is not going through wildApprox when I guess it should.

I'll close this MR then.

traverse(wildApprox(dealias))
case t: TypeRef =>
if isAnchor(t.symbol) then
parts += t
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36 changes: 36 additions & 0 deletions tests/neg/i17305.scala
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Original file line number Diff line number Diff line change
@@ -0,0 +1,36 @@
trait Wrapper[A1] {
def use(a: A1 => Unit): Unit
}

trait Assertion[A2] {}

def hideTypeInOut[A3](
c1: A3
)(using
hider: HideAInOut[A3]
): Wrapper[hider.Out] = ???

def entryPoint(): Unit = {
hideTypeInOut(1L)
.use((pair) => myAssert(pair)(someAssertion(2))) // error Assertion[Int] instead of Assertion[Long]
}

private def myAssert[A4](a: A4)(assertion: Assertion[A4]): Unit = ()

private def someAssertion(i: Int): Assertion[Int] = ???

trait HideAInOut[-A] {
type Out
def get(left: A): Out
}

object HideAInOut {

type Out[HideA, HideB] = HideAInOut[HideA] { type Out = HideB }

given [GivenA]: HideAInOut.Out[GivenA, GivenA] =
new HideAInOut[GivenA] {
type Out = GivenA
def get(left: GivenA): Out = left
}
}