Supported filterIndexedTo

idea/src/org/jetbrains/kotlin/idea/intentions/loopToCallChain/result/AddToCollectionTransformation.kt

@@ -22,10 +22,7 @@ import org.jetbrains.kotlin.descriptors.VariableDescriptor
 import org.jetbrains.kotlin.idea.caches.resolve.resolveToDescriptor
 import org.jetbrains.kotlin.idea.imports.importableFqName
 import org.jetbrains.kotlin.idea.intentions.loopToCallChain.*
-import org.jetbrains.kotlin.idea.intentions.loopToCallChain.sequence.FilterTransformation
+import org.jetbrains.kotlin.idea.intentions.loopToCallChain.sequence.*
-import org.jetbrains.kotlin.idea.intentions.loopToCallChain.sequence.FlatMapTransformation
-import org.jetbrains.kotlin.idea.intentions.loopToCallChain.sequence.MapIndexedTransformation
-import org.jetbrains.kotlin.idea.intentions.loopToCallChain.sequence.MapTransformation
 import org.jetbrains.kotlin.idea.util.IdeDescriptorRenderers
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.psi.*
@@ -43,6 +40,10 @@ class AddToCollectionTransformation(
                 FilterToTransformation.create(loop, previousTransformation.inputVariable, targetCollection, previousTransformation.effectiveCondition()) //TODO: use filterNotTo?
             }
 
+            is FilterIndexedTransformation -> {
+                FilterIndexedToTransformation.create(loop, previousTransformation.inputVariable, previousTransformation.indexVariable, targetCollection, previousTransformation.condition)
+            }
+
             is MapTransformation -> {
                 MapToTransformation.create(loop, previousTransformation.inputVariable, targetCollection, previousTransformation.mapping)
             }
@@ -216,6 +217,42 @@ class FilterToTransformation private constructor(
     }
 }
 
+class FilterIndexedToTransformation private constructor(
+        loop: KtForExpression,
+        private val inputVariable: KtCallableDeclaration,
+        private val indexVariable: KtCallableDeclaration,
+        private val targetCollection: KtExpression,
+        private val filter: KtExpression
+) : ReplaceLoopResultTransformation(loop) {
+
+    override val presentation: String
+        get() = "filterIndexedTo(){}"
+
+    override fun generateCode(chainedCallGenerator: ChainedCallGenerator): KtExpression {
+        val lambda = generateLambda(filter, indexVariable, inputVariable)
+        return chainedCallGenerator.generate("filterIndexedTo($0) $1:'{}'", targetCollection, lambda)
+    }
+
+    companion object {
+        fun create(
+                loop: KtForExpression,
+                inputVariable: KtCallableDeclaration,
+                indexVariable: KtCallableDeclaration,
+                targetCollection: KtExpression,
+                filter: KtExpression
+        ): ResultTransformation {
+            val initialization = targetCollection.detectInitializationBeforeLoop(loop, checkNoOtherUsagesInLoop = true)
+            if (initialization != null && initialization.initializer.hasNoSideEffect()) {
+                val transformation = FilterIndexedToTransformation(loop, inputVariable, indexVariable, initialization.initializer, filter)
+                return AssignToVariableResultTransformation.createDelegated(transformation, initialization)
+            }
+            else {
+                return FilterIndexedToTransformation(loop, inputVariable, indexVariable, targetCollection, filter)
+            }
+        }
+    }
+}
+
 class MapToTransformation private constructor(
         loop: KtForExpression,
         private val inputVariable: KtCallableDeclaration,

idea/testData/intentions/loopToCallChain/filterIndexedTo.kt

@@ -0,0 +1,8 @@
+// WITH_RUNTIME
+// INTENTION_TEXT: "Replace with 'filterIndexedTo(){}'"
+fun foo(list: List<String>, target: MutableList<String>) {
+    <caret>for ((index, s) in list.withIndex()) {
+        if (s.length > index)
+            target.add(s)
+    }
+}

idea/testData/intentions/loopToCallChain/filterIndexedTo.kt.after

@@ -0,0 +1,5 @@
+// WITH_RUNTIME
+// INTENTION_TEXT: "Replace with 'filterIndexedTo(){}'"
+fun foo(list: List<String>, target: MutableList<String>) {
+    <caret>list.filterIndexedTo(target) { index, s -> s.length > index }
+}

idea/testData/intentions/loopToCallChain/filterIndexedTo2.kt

@@ -0,0 +1,12 @@
+// WITH_RUNTIME
+// INTENTION_TEXT: "Replace with 'filterIndexedTo(){}'"
+import java.util.ArrayList
+
+fun foo(list: List<String>): List<String> {
+    val result = ArrayList<String>(1000)
+    <caret>for ((index, s) in list.withIndex()) {
+        if (s.length > index)
+            result.add(s)
+    }
+    return result
+}

idea/testData/intentions/loopToCallChain/filterIndexedTo2.kt.after

@@ -0,0 +1,8 @@
+// WITH_RUNTIME
+// INTENTION_TEXT: "Replace with 'filterIndexedTo(){}'"
+import java.util.ArrayList
+
+fun foo(list: List<String>): List<String> {
+    val <caret>result = list.filterIndexedTo(ArrayList<String>(1000)) { index, s -> s.length > index }
+    return result
+}

idea/testData/intentions/loopToCallChain/filterIndexed_twoIndices.kt

@@ -1,5 +1,5 @@
 // WITH_RUNTIME
-// INTENTION_TEXT: "Replace with '+= filterIndexed{}.filterIndexed{}'"
+// INTENTION_TEXT: "Replace with 'filterIndexed{}.filterIndexedTo(){}'"
 fun foo(list: List<String>, target: MutableCollection<String>) {
     var j = 0
     <caret>for ((i, s) in list.withIndex()) {

idea/testData/intentions/loopToCallChain/filterIndexed_twoIndices.kt.after

@@ -1,7 +1,7 @@
 // WITH_RUNTIME
-// INTENTION_TEXT: "Replace with '+= filterIndexed{}.filterIndexed{}'"
+// INTENTION_TEXT: "Replace with 'filterIndexed{}.filterIndexedTo(){}'"
 fun foo(list: List<String>, target: MutableCollection<String>) {
-    <caret>target += list
+    <caret>list
             .filterIndexed { i, s -> s.length <= i }
-            .filterIndexed { j, s -> s.length % j == 0 }
+            .filterIndexedTo(target) { j, s -> s.length % j == 0 }
 }