"contains" now requires to be marked as operator + no heuristic signature for contains needed anymore

idea/idea-completion/testData/smart/inOperator/ExtensionContains.kt

@@ -2,7 +2,8 @@ interface X
 interface Y : X
 interface Z
 
-fun X.contains(s: String): Boolean
+operator fun X.contains(s: String): Boolean = true
+fun Z.contains(s: String): Boolean = true
 
 fun foo(s: String, x: X, y: Y, z: Z) {
     if (s in <caret>)

idea/idea-completion/testData/smart/inOperator/FilterByArgumentType.kt

@@ -1,13 +1,13 @@
 interface X {
-    fun contains(s: String): Boolean
+    operator fun contains(s: String): Boolean
 }
 
 interface Y {
-    fun contains(i: Int): Boolean
+    operator fun contains(i: Int): Boolean
 }
 
 interface Z {
-    fun contains(o: Any): Boolean
+    operator fun contains(o: Any): Boolean
 }
 
 fun foo(s: String, x: X, y: Y, z: Z) {

idea/idea-completion/testData/smart/inOperator/GenericMethod2.kt

@@ -1,5 +1,5 @@
 interface X<T> {
-    fun contains(t: T): Boolean
+    operator fun contains(t: T): Boolean
 }
 
 interface A {

idea/idea-completion/testData/smart/inOperator/GenericMethod3.kt

@@ -1,6 +1,6 @@
 interface X<T>
 
-fun<T> X<T>.contains(t: T): Boolean
+operator fun<T> X<T>.contains(t: T): Boolean = true
 
 interface A {
     fun<T> createX(t: T): X<T>

idea/idea-completion/testData/smart/inOperator/NonBooleanContains.kt

@@ -1,5 +1,5 @@
 interface X {
-    fun contains(s: String): Boolean?
+    operator fun contains(s: String): Boolean?
 }
 
 fun foo(s: String, x: X) {