Extension callables index and its use in completion

idea/testData/completion/basic/multifile/NotImportedExtensionFunction/NotImportedExtensionFunction.dependency.kt

@@ -1,6 +1,6 @@
 package second
 
-fun String.helloFun() {
+fun String?.helloFun() {
 }
 
 fun String.helloWithParams(i : Int) : String {
@@ -10,5 +10,8 @@ fun String.helloWithParams(i : Int) : String {
 fun String.helloFunPreventAutoInsert() {
 }
 
+fun <T: CharSequence> T.helloFunGeneric() {
+}
+
 fun Int.helloFake() {
 }

idea/testData/completion/basic/multifile/NotImportedExtensionFunction/NotImportedExtensionFunction.kt

@@ -8,5 +8,6 @@ fun firstFun() {
 // EXIST: helloFun
 // EXIST: helloFunPreventAutoInsert
 // EXIST: helloWithParams
+// EXIST: helloFunGeneric
 // ABSENT: helloFake
-// NUMBER: 3
+// NUMBER: 4

idea/testData/completion/basic/multifile/NotImportedExtensionFunction2/NotImportedExtensionFunction2.dependency.kt

@@ -0,0 +1,16 @@
+package second
+
+fun (() -> Unit)?.helloFun1() {
+}
+
+fun Function0<Unit>.helloFun2() {
+}
+
+fun ExtensionFunction0<String, Unit>.helloFun3() {
+}
+
+fun Function1<String, Unit>.helloFun4() {
+}
+
+fun Any.helloAny() {
+}

idea/testData/completion/basic/multifile/NotImportedExtensionFunction2/NotImportedExtensionFunction2.kt

@@ -0,0 +1,12 @@
+package first
+
+fun firstFun(p: () -> Unit) {
+    p.hello<caret>
+}
+
+// EXIST: helloFun1
+// EXIST: helloFun2
+// EXIST: helloAny
+// ABSENT: helloFun3
+// ABSENT: helloFun4
+// NUMBER: 3