Implement extension of method usages search to cover usages of overriding functions in Kotlin

idea/testData/findUsages/findMethodUsages/javaMethodUsages.0.kt

@@ -2,6 +2,10 @@
 // OPTIONS: usages
 package testing;
 
-public class Server() {
-    public fun <caret>processRequest() = "foo"
+public open class Server() {
+    public open fun <caret>processRequest() = "foo"
+}
+
+public class ServerEx(): Server() {
+    public override fun processRequest() = "foofoo"
 }

idea/testData/findUsages/findMethodUsages/javaMethodUsages.1.java

@@ -2,7 +2,7 @@ import testing.*;
 
 class Client {
     public void foo() {
-        Server server = new Server();
-        server.processRequest();
+        new Server().processRequest();
+        new ServerEx().processRequest();
     }
 }

idea/testData/findUsages/findMethodUsages/javaMethodUsages.results.txt

@@ -1 +1,2 @@
-Unclassified usage (6: 16) server.processRequest();
+Unclassified usage (5: 22) new Server().processRequest();
+Unclassified usage (6: 24) new ServerEx().processRequest();

idea/testData/findUsages/findMethodUsages/kotlinMethodUsages.0.kt

@@ -2,5 +2,11 @@
 // OPTIONS: usages
 package server;
 
-fun <caret>processRequest() = "foo"
+public open class Server() {
+    open fun <caret>processRequest() = "foo"
+}
+
+public class ServerEx(): Server() {
+    override fun processRequest() = "foofoo"
+}
 

idea/testData/findUsages/findMethodUsages/kotlinMethodUsages.1.kt

@@ -1,12 +1,8 @@
-package client
-
-import server.processRequest
+import server.*;
 
 class Client {
-    val methodRef = ::processRequest()
-
-    fun doProcessRequest() {
-        println("Process...")
-        processRequest()
+    public fun foo() {
+        Server().processRequest()
+        ServerEx().processRequest()
     }
-}
+}

idea/testData/findUsages/findMethodUsages/kotlinMethodUsages.results.txt

@@ -1,3 +1,2 @@
-Callable reference (6: 23) val methodRef = ::processRequest()
-Function call (10: 9) processRequest()
-Import directive (3: 15) import server.processRequest
+Function call (5: 18) Server().processRequest()
+Function call (6: 20) ServerEx().processRequest()

idea/testData/findUsages/findMethodUsages/kotlinOverloadAndExtensionUsages.results.txt

@@ -3,4 +3,5 @@ Function call (11: 7) x.foo(1, 2)
 Function call (25: 5) foo(t)
 Function call (30: 7) a.foo(1, "")
 Function call (35: 9) foo(t)
+Function call (39: 5) foo(s)
 Function call (3: 18) super<A>.foo(t)

idea/testData/findUsages/findMethodUsages/kotlinTopLevelMethodUsages.0.kt

@@ -0,0 +1,6 @@
+// PSI_ELEMENT: org.jetbrains.jet.lang.psi.JetNamedFunction
+// OPTIONS: usages
+package server;
+
+fun <caret>processRequest() = "foo"
+

idea/testData/findUsages/findMethodUsages/kotlinTopLevelMethodUsages.1.kt

@@ -0,0 +1,12 @@
+package client
+
+import server.processRequest
+
+class Client {
+    val methodRef = ::processRequest()
+
+    fun doProcessRequest() {
+        println("Process...")
+        processRequest()
+    }
+}

idea/testData/findUsages/findMethodUsages/kotlinTopLevelMethodUsages.results.txt

@@ -0,0 +1,3 @@
+Callable reference (6: 23) val methodRef = ::processRequest()
+Function call (10: 9) processRequest()
+Import directive (3: 15) import server.processRequest