Ycheck fails with bad interaction between inline parameters and singleton types

[nicolasstucki]

Minimized code

inline def summonA[T](using x: T): x.type = x
inline def summonB[T](using inline x: T): x.type = x
inline def summonC[T](using inline x: T): T = x

trait Foo:
  def f: Int = 9

def test(using Foo) =
  summonA[Foo].f
  summonB[Foo].f
  summonC[Foo].f
  ()

Output

10 |  summonB[Foo].f
   |  ^^^^^^^^^^^^^^
   |  value f is not a member of T

Expectation

summonB[Foo].f should compile

[nicolasstucki]

Workaround

transparent inline def summonD[T](using inline x: T): T = x

or

transparent inline def summonD[T](using inline x: T): x.type = x

[odersky]

This now fails Ycheck after phase inlining with

*** error while checking i11163.scala after phase inlining ***
exception occurred while compiling i11163.scala
java.lang.AssertionError: assertion failed: Selection (x$1:x$1.type).f with type T#f.type does not have a denotation while compiling i11163.scala
Exception in thread "main" java.lang.AssertionError: assertion failed: Selection (x$1:x$1.type).f with type T#f.type does not have a denotation

The offending line is this:

exception while typing (x$1:x$1.type).f of class class dotty.tools.dotc.ast.Trees$Select # -1