Supported "is" in when entry condition

idea/idea-analysis/src/org/jetbrains/kotlin/idea/search/usagesSearch/destructuringDeclarationUsages.kt

@@ -238,6 +238,12 @@ private class Processor(
                                 return true
                             }
 
+                            is KtWhenConditionIsPattern -> {
+                                //TODO: smart cast is possible outside of when or inside other branches!
+                                usePlainSearch(typeRefParent.parent as KtWhenEntry)
+                                return true
+                            }
+
                             is KtBinaryExpressionWithTypeRHS -> {
                                 processSuspiciousExpression(typeRefParent)
                                 return true

idea/testData/findUsages/kotlin/conventions/components/dataClass.2.kt

@@ -32,3 +32,15 @@ fun y(o: Any) {
     val list = o as List<A>
     val (x, y) = list[0]
 }
+
+fun z(o: Any) {
+    when (o) {
+        is A -> {
+            val (x, y) = o
+        }
+
+        is String -> TODO()
+
+        else -> return
+    }
+}

idea/testData/findUsages/kotlin/conventions/components/dataClass.results.txt

@@ -10,6 +10,7 @@
 [dataClass.2.kt] Value read 26 val (x, y) = o
 [dataClass.2.kt] Value read 27 val (x1, y1) = A(1, "", "")
 [dataClass.2.kt] Value read 33 val (x, y) = list[0]
+[dataClass.2.kt] Value read 39 val (x, y) = o
 [dataClass.2.kt] Value read 5 a.n
 [dataClass.2.kt] Value read 8 val (x, y, z) = a
 [dataClass.2.kt] Value read 9 val (x1, y1, z1) = f()