Merge pull request #4637 from dotty-staging/fix-i4586

Fix #4586: Add regression test

Author: odersky

tests/pos/i4586.scala

@@ -0,0 +1,4 @@
+class Foo {
+  inline def foo1(f: => Int => Int): Int = f(7)
+  def bar1 = foo1(x => x + 1)
+}