Implicit search failure for context functions

[odersky]

Compiler version

3.1.1-RC2

Minimized example

class Dummy
given Dummy = ???
trait Foo
given foo: Foo = ???

object Test:
  summon[Dummy ?=> Foo] // fails
  summon[Dummy ?=> Foo](using foo)  // works
  summon[Dummy ?=> Foo](using (_: Dummy) ?=> foo)  // works

Output

-- Error: ../new/test.scala:7:23 -----------------------------------------------
7 |  summon[Dummy ?=> Foo] // fails
  |                       ^
  |no implicit argument of type (Dummy) ?=> Foo was found for parameter x of method summon in object Predef.
  |I found:
  |
  |    foo
  |
  |But given instance foo does not match type (Dummy) ?=> Foo.

Expectation

Should compile.