Finding implicit usages of companion object in containing class.

idea/testData/findUsages/kotlin/defaultObject/inContainingClass.0.kt

@@ -0,0 +1,26 @@
+// PSI_ELEMENT: org.jetbrains.kotlin.psi.JetObjectDeclaration
+// OPTIONS: usages
+class A {
+    init {
+        foo()
+        v
+
+        1[2] // using companion object function by convention
+
+        ext() // companion object is extension receiver
+    }
+
+    companion <caret>object: Foo {
+        fun foo() {
+        }
+
+        val v = 42
+
+        fun Int.get(a: Int) = this + a
+    }
+}
+
+trait Foo
+
+fun Foo.ext() {
+}

idea/testData/findUsages/kotlin/defaultObject/inContainingClass.results.txt

@@ -0,0 +1,4 @@
+Function call (10: 9) ext() // companion object is extension receiver
+Function call (5: 9) foo()
+Implicit 'get' (8: 9) 1[2] // using companion object function by convention
+Value read (6: 9) v