Inline by name function argument generates wrong tree

[nicolasstucki]

class Foo {
  inline def foo1(f: => Int => Int): Int = f(7)
  def bar1 = foo1(x => x + 1)
}

package <empty> {
  class Foo() extends Object() { 
    inline def foo1(f: => Function1[Int, Int]): Int = f.apply(7)
    def bar1: Int = 
      /* inlined from 
        this.foo1(
          {
            def $anonfun(x: Int): Int = x.+(1)
            closure($anonfun)
          }
        )
      */ 
        {
          $anonfun(7)
        }
  }
}

which then crashes with

Exception in thread "main" java.lang.AssertionError: assertion failed: unresolved symbols: method $anonfun when pickling Foo.scala
	at scala.Predef$.assert(Predef.scala:219)
	at dotty.tools.dotc.core.tasty.TreePickler.pickle(TreePickler.scala:640)
	at dotty.tools.dotc.transform.Pickler.$anonfun$run$3(Pickler.scala:56)
	at dotty.tools.dotc.transform.Pickler.$anonfun$run$3$adapted(Pickler.scala:49)
	at scala.collection.immutable.List.foreach(List.scala:389)
	at dotty.tools.dotc.transform.Pickler.$anonfun$run$2(Pickler.scala:49)
	at dotty.tools.dotc.transform.Pickler.$anonfun$run$2$adapted(Pickler.scala:48)
	at scala.collection.immutable.List.foreach(List.scala:389)
	at dotty.tools.dotc.transform.Pickler.run(Pickler.scala:48)
	....

[nicolasstucki]

@odersky this is another issue we have with plain inlining of by name functions. This does work with splices and quotes as shown in #4584.

[odersky]

This should be fixed by now.

[nicolasstucki]

I will add a regression test for it.