if then to elvis: propose transformation to 'let' #KT-26653 Fixed

idea/src/org/jetbrains/kotlin/idea/inspections/branchedTransformations/IfThenToSafeAccessInspection.kt

@@ -93,12 +93,14 @@ class IfThenToSafeAccessInspection : AbstractApplicabilityBasedInspection<KtIfEx
         else -> false
     }
 
-    private fun KtSafeQualifiedExpression.renameLetParameter(editor: Editor) {
+    companion object {
-        val callExpression = selectorExpression as? KtCallExpression ?: return
+        internal fun KtSafeQualifiedExpression.renameLetParameter(editor: Editor) {
-        if (callExpression.calleeExpression?.text != "let") return
+            val callExpression = selectorExpression as? KtCallExpression ?: return
-        val parameter = callExpression.lambdaArguments.singleOrNull()?.getLambdaExpression()?.valueParameters?.singleOrNull() ?: return
+            if (callExpression.calleeExpression?.text != "let") return
-        PsiDocumentManager.getInstance(project).doPostponedOperationsAndUnblockDocument(editor.document)
+            val parameter = callExpression.lambdaArguments.singleOrNull()?.getLambdaExpression()?.valueParameters?.singleOrNull() ?: return
-        editor.caretModel.moveToOffset(parameter.startOffset)
+            PsiDocumentManager.getInstance(project).doPostponedOperationsAndUnblockDocument(editor.document)
-        KotlinVariableInplaceRenameHandler().doRename(parameter, editor, null)
+            editor.caretModel.moveToOffset(parameter.startOffset)
+            KotlinVariableInplaceRenameHandler().doRename(parameter, editor, null)
+        }
     }
 }

idea/src/org/jetbrains/kotlin/idea/intentions/branchedTransformations/intentions/IfThenToElvisIntention.kt

@@ -23,6 +23,7 @@ import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.core.replaced
 import org.jetbrains.kotlin.idea.inspections.IntentionBasedInspection
+import org.jetbrains.kotlin.idea.inspections.branchedTransformations.IfThenToSafeAccessInspection
 import org.jetbrains.kotlin.idea.intentions.SelfTargetingOffsetIndependentIntention
 import org.jetbrains.kotlin.idea.intentions.branchedTransformations.*
 import org.jetbrains.kotlin.idea.util.application.runWriteAction
@@ -54,6 +55,8 @@ class IfThenToElvisIntention : SelfTargetingOffsetIndependentIntention<KtIfExpre
                 false
             baseClause.evaluatesTo(receiverExpression) ->
                 true
+            baseClause.anyArgumentEvaluatesTo(receiverExpression) ->
+                true
             hasImplicitReceiverReplaceableBySafeCall() || baseClause.hasFirstReceiverOf(receiverExpression) ->
                 !baseClause.hasNullableType(context)
             else ->
@@ -95,6 +98,9 @@ class IfThenToElvisIntention : SelfTargetingOffsetIndependentIntention<KtIfExpre
 
         if (editor != null) {
             elvis.inlineLeftSideIfApplicableWithPrompt(editor)
+            with(IfThenToSafeAccessInspection) {
+                (elvis.left as? KtSafeQualifiedExpression)?.renameLetParameter(editor)
+            }
         }
     }
 }

idea/testData/intentions/branched/ifThenToElvis/replaceWithLet.kt

@@ -0,0 +1,12 @@
+// WITH_RUNTIME
+
+fun foo(s: String?) {
+    val x = <caret>if (s != null) {
+        bar(s)
+    }
+    else {
+        13
+    }
+}
+
+fun bar(s: String): Int = 42

idea/testData/intentions/branched/ifThenToElvis/replaceWithLet.kt.after

@@ -0,0 +1,7 @@
+// WITH_RUNTIME
+
+fun foo(s: String?) {
+    val x = s?.let { bar(it) } ?: 13
+}
+
+fun bar(s: String): Int = 42

idea/testData/intentions/branched/ifThenToElvis/replaceWithLetAndRenameIt.kt

@@ -0,0 +1,12 @@
+// WITH_RUNTIME
+
+fun foo(it: String?) {
+    val x = <caret>if (it != null) {
+        bar(it)
+    }
+    else {
+        13
+    }
+}
+
+fun bar(s: String): Int = 42

idea/testData/intentions/branched/ifThenToElvis/replaceWithLetAndRenameIt.kt.after

@@ -0,0 +1,7 @@
+// WITH_RUNTIME
+
+fun foo(it: String?) {
+    val x = it?.let { it1 -> bar(it1) } ?: 13
+}
+
+fun bar(s: String): Int = 42

idea/testData/intentions/branched/ifThenToElvis/replaceWithLetInMember.kt

@@ -1,4 +1,3 @@
-// IS_APPLICABLE: false
 // WITH_RUNTIME
 
 class Test {
@@ -6,9 +5,8 @@ class Test {
         return param1
     }
 
-    fun doAThingIfPresent(param1: String?) {
+    fun doAThingIfPresent(param1: String?): String {
-        // In theory could propose transformation to 'let'
+        return <caret>if (param1 != null) {
-        <caret>if (param1 != null) {
             doAThing(param1)
         } else {
             ""

idea/testData/intentions/branched/ifThenToElvis/replaceWithLetInMember.kt.after

@@ -0,0 +1,11 @@
+// WITH_RUNTIME
+
+class Test {
+    fun doAThing(param1: String): String {
+        return param1
+    }
+
+    fun doAThingIfPresent(param1: String?): String {
+        return param1?.let { doAThing(it) } ?: ""
+    }
+}

idea/testData/intentions/branched/ifThenToElvis/replaceWithLetInMemberWithIs.kt

@@ -1,4 +1,3 @@
-// IS_APPLICABLE: false
 // WITH_RUNTIME
 
 class Test {
@@ -6,9 +5,8 @@ class Test {
         return param1
     }
 
-    fun doAThingIfPresent(param1: String?) {
+    fun doAThingIfPresent(param1: Any?): String {
-        // In theory could propose transformation to 'let'
+        return <caret>if (param1 is String) {
-        <caret>if (param1 is String) {
             doAThing(param1)
         } else {
             ""

idea/testData/intentions/branched/ifThenToElvis/replaceWithLetInMemberWithIs.kt.after

@@ -0,0 +1,11 @@
+// WITH_RUNTIME
+
+class Test {
+    fun doAThing(param1: String): String {
+        return param1
+    }
+
+    fun doAThingIfPresent(param1: Any?): String {
+        return (param1 as? String)?.let { doAThing(it) } ?: ""
+    }
+}

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

@@ -2441,6 +2441,16 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
                 runTest("idea/testData/intentions/branched/ifThenToElvis/otherBlockHasMoreThanOneStatement.kt");
             }
 
+            @TestMetadata("replaceWithLet.kt")
+            public void testReplaceWithLet() throws Exception {
+                runTest("idea/testData/intentions/branched/ifThenToElvis/replaceWithLet.kt");
+            }
+
+            @TestMetadata("replaceWithLetAndRenameIt.kt")
+            public void testReplaceWithLetAndRenameIt() throws Exception {
+                runTest("idea/testData/intentions/branched/ifThenToElvis/replaceWithLetAndRenameIt.kt");
+            }
+
             @TestMetadata("replaceWithLetInMember.kt")
             public void testReplaceWithLetInMember() throws Exception {
                 runTest("idea/testData/intentions/branched/ifThenToElvis/replaceWithLetInMember.kt");