Implicit search sometimes fails to check if self type matches conversion function

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I've come across an example where the implicit resolution procedure fails to notice that it can provide the no-op function x => x as an implicit function argument. Example attached. It's short but it's not really minimal - hope it's enough.

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Imported From: https://issues.scala-lang.org/browse/SI-3725?orig=1
Reporter: Daniel Ramage (dramage)
Attachments:

• bug.scala (created on Aug 4, 2010 6:15:42 AM UTC, 1992 bytes)

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@lrytz said:
here's a simplified version of the example

class D[T, U](x: T)(implicit toIt: T => Iterable[U]) { def foo(id: U => Int) = 0 }
implicit def iD[T, U](x: T)(implicit toIt: T => Iterable[U]) = new D(x)

val data : Iterable[Int] = List(1,2)

// OK
iD(data).foo((x: Int) => x)

// data.foo((x: Int) => x)
// <console>:16: error: could not find implicit value for parameter toIt: (Iterable[Int]) => Iterable[U]
//        data.foo((x: Int) => x)
//        ^

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@adriaanm said:
duplicate of #3201 (see also #3346, #2781)
this should be fixed in 2.8.1