Support 'it op something' case in "redundant let" #KT-21373 Fixed

idea/src/org/jetbrains/kotlin/idea/intentions/ReplaceSingleLineLetIntention.kt

@@ -90,21 +90,35 @@ class ReplaceSingleLineLetIntention : SelfTargetingOffsetIndependentIntention<Kt
         }
     }
 
-    private fun KtBinaryExpression.isApplicable(parameterName: String): Boolean {
+    private fun KtBinaryExpression.isApplicable(parameterName: String, isTopLevel: Boolean = true): Boolean {
         val left = left ?: return false
-        when (left) {
+        if (isTopLevel) {
-            is KtNameReferenceExpression -> if (left.text != parameterName) return false
+            when (left) {
-            is KtDotQualifiedExpression -> if (!left.isApplicable(parameterName)) return false
+                is KtNameReferenceExpression -> if (left.text != parameterName) return false
-            else -> return false
+                is KtDotQualifiedExpression -> if (!left.isApplicable(parameterName)) return false
+                else -> return false
+            }
+        }
+        else {
+            if (!left.isApplicable(parameterName)) return false
         }
 
         val right = right ?: return false
-        return when (right) {
+        return right.isApplicable(parameterName)
-            is KtNameReferenceExpression -> right.text != parameterName
+    }
-            is KtDotQualifiedExpression -> !right.hasLambdaExpression() && !right.nameUsed(parameterName)
+
-            is KtConstantExpression -> true
+    private fun KtExpression.isApplicable(parameterName: String): Boolean = when (this) {
-            else -> false
+        is KtNameReferenceExpression -> text != parameterName
-        }
+        is KtDotQualifiedExpression -> !hasLambdaExpression() && !nameUsed(parameterName)
+        is KtBinaryExpression -> isApplicable(parameterName, isTopLevel = false)
+        is KtCallExpression -> isApplicable(parameterName)
+        is KtConstantExpression -> true
+        else -> false
+    }
+
+    private fun KtCallExpression.isApplicable(parameterName: String): Boolean = valueArguments.all {
+        val argumentExpression = it.getArgumentExpression() ?: return@all false
+        argumentExpression.isApplicable(parameterName)
     }
 
     private fun KtDotQualifiedExpression.isApplicable(parameterName: String) =

idea/testData/intentions/replaceSingleLineLetIntention/in.kt

@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: true
+
+fun foo(list: List<Int>) {
+    list.filter { it.let<caret> { it in 1000..3000 } }
+}

idea/testData/intentions/replaceSingleLineLetIntention/in.kt.after

@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: true
+
+fun foo(list: List<Int>) {
+    list.filter { it in 1000..3000 }
+}

idea/testData/intentions/replaceSingleLineLetIntention/inWithMultipleParam.kt

@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: false
+
+fun foo(list: List<Int>) {
+    list.filter { it.let<caret> { value -> value in value..3000 } }
+}

idea/testData/intentions/replaceSingleLineLetIntention/inWithRange.kt

@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: true
+
+fun foo(list: List<Int>) {
+    list.filter { it.let<caret> { it in IntRange(1, 10) } }
+}

idea/testData/intentions/replaceSingleLineLetIntention/inWithRange.kt.after

@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: true
+
+fun foo(list: List<Int>) {
+    list.filter { it in IntRange(1, 10) }
+}

idea/testData/intentions/replaceSingleLineLetIntention/inWithRangeMultipleParam.kt

@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: false
+
+fun foo(list: List<Int>) {
+    list.filter { it.let<caret> { it in IntRange(it - 1, 10) } }
+}

idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java

@@ -14174,6 +14174,30 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("in.kt")
+        public void testIn() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/in.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("inWithMultipleParam.kt")
+        public void testInWithMultipleParam() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/inWithMultipleParam.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("inWithRange.kt")
+        public void testInWithRange() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/inWithRange.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("inWithRangeMultipleParam.kt")
+        public void testInWithRangeMultipleParam() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/inWithRangeMultipleParam.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("lambdaWithBinaryExpression.kt")
         public void testLambdaWithBinaryExpression() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/replaceSingleLineLetIntention/lambdaWithBinaryExpression.kt");