Classified usages in up casts correctly.

#KT-7047 fixed

idea/idea-analysis/src/org/jetbrains/kotlin/idea/findUsages/UsageTypeUtils.kt

@@ -109,7 +109,7 @@ public object UsageTypeUtils {
 
                 with(refExpr.getParentOfTypeAndBranch<JetBinaryExpressionWithTypeRHS>(){ getRight() }) {
                     val opType = this?.getOperationReference()?.getReferencedNameElementType()
-                    opType == JetTokens.AS_KEYWORD || opType == JetTokens.AS_SAFE
+                    opType == JetTokens.AS_KEYWORD || opType == JetTokens.AS_SAFE || opType == JetTokens.COLON
                 } ->
                     CLASS_CAST_TO
 

idea/testData/findUsages/kotlin/findClassUsages/kotlinClassAllUsages.1.kt

@@ -41,5 +41,5 @@ fun Any.asServer(): Server? {
     when (this) {
         is Server -> println("Server!")
     }
-    return if (this is Server) this as Server else null
+    return if (this is Server) this: Server else this as? Server
 }

idea/testData/findUsages/kotlin/findClassUsages/kotlinClassAllUsages.results.txt

@@ -12,6 +12,7 @@ Supertype (23: 23) companion object: Server() {
 Supertype (28: 22) object ClientObject: Server() {
 Supertype (5: 43) class Client(name: String = Server.NAME): Server() {
 Target type of 'is' operation (42: 12) is Server -> println("Server!")
-Target type of 'is' operation (44: 24) return if (this is Server) this as Server else null
-Usage in cast target type (44: 40) return if (this is Server) this as Server else null
+Target type of 'is' operation (44: 24) return if (this is Server) this: Server else this as? Server
+Usage in cast target type (44: 38) return if (this is Server) this: Server else this as? Server
+Usage in cast target type (44: 59) return if (this is Server) this: Server else this as? Server
 Usage in import (3: 15) import server.Server