Synthetic extensions wins against top-level extension.

compiler/testData/diagnostics/tests/resolve/priority/syntheticPropertiesVsMembers.kt

@@ -0,0 +1,38 @@
+// !CHECK_TYPE
+// !DIAGNOSTICS: -UNUSED_EXPRESSION -UNUSED_PARAMETER -UNUSED_VARIABLE
+
+// FILE: A.java
+public class A {
+    public A getFoo() { return 3; }
+}
+
+// FILE: B.java
+public class B {
+    public B getFoo() { return ""; }
+}
+
+// FILE: 1.kt
+class C(val foo: C)
+
+fun test(a: A, b: B, c: C) {
+    with(a) {
+        with(b) {
+            foo checkType { _<B>() }
+        }
+        foo checkType { _<A>() }
+    }
+
+    with(a) {
+        with(c) {
+            foo checkType { _<C>() }
+        }
+    }
+
+    with(c) {
+        with(a) {
+            foo checkType { _<C>() } // todo
+        }
+    }
+}
+
+fun <T, R> with(receiver: T, f: T.() -> R): R = receiver.f()