"Replace 'if' with elvis operator": don't suggest if val initializer is a complex expression

#KT-35165 Fixed

idea/src/org/jetbrains/kotlin/idea/inspections/FoldInitializerAndIfToElvisInspection.kt

@@ -19,6 +19,7 @@ import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.caches.resolve.resolveToDescriptorIfAny
 import org.jetbrains.kotlin.idea.core.replaced
 import org.jetbrains.kotlin.idea.core.setType
+import org.jetbrains.kotlin.idea.core.util.isMultiLine
 import org.jetbrains.kotlin.idea.intentions.branchedTransformations.elvisPattern
 import org.jetbrains.kotlin.idea.intentions.branchedTransformations.expressionComparedToNull
 import org.jetbrains.kotlin.idea.intentions.branchedTransformations.fromIfKeywordToRightParenthesisTextRangeInThis
@@ -63,6 +64,11 @@ class FoldInitializerAndIfToElvisInspection : AbstractApplicabilityBasedInspecti
         private fun applicabilityRange(element: KtIfExpression): TextRange? {
             val data = calcData(element) ?: return null
 
+            if (data.initializer !is KtParenthesizedExpression
+                && data.initializer.isMultiLine()
+                && createElvisExpression(element, data, KtPsiFactory(element)).left is KtParenthesizedExpression
+            ) return null
+
             val type = data.ifNullExpression.analyze().getType(data.ifNullExpression) ?: return null
             if (!type.isNothing()) return null
 
@@ -72,7 +78,8 @@ class FoldInitializerAndIfToElvisInspection : AbstractApplicabilityBasedInspecti
         fun isApplicable(element: KtIfExpression): Boolean = applicabilityRange(element) != null
 
         fun applyTo(element: KtIfExpression): KtBinaryExpression {
-            val (initializer, declaration, ifNullExpr, typeReference) = calcData(element)!!
+            val data = calcData(element)!!
+            val (initializer, declaration, _, typeReference) = data
             val factory = KtPsiFactory(element)
 
             val explicitTypeToSet = when {
@@ -90,11 +97,7 @@ class FoldInitializerAndIfToElvisInspection : AbstractApplicabilityBasedInspecti
             val commentSaver = CommentSaver(childRangeBefore)
             val childRangeAfter = childRangeBefore.withoutLastStatement()
 
-            val margin = CodeStyle.getSettings(element.containingKtFile).defaultRightMargin
+            val elvis = createElvisExpression(element, data, factory)
-            val declarationTextLength = declaration.text.split("\n").lastOrNull()?.trim()?.length ?: 0
-            val pattern = elvisPattern(declarationTextLength + ifNullExpr.textLength + 5 >= margin || element.then?.hasComments() == true)
-
-            val elvis = factory.createExpressionByPattern(pattern, initializer, ifNullExpr) as KtBinaryExpression
 
             return runWriteAction {
                 if (typeReference != null) {
@@ -112,6 +115,14 @@ class FoldInitializerAndIfToElvisInspection : AbstractApplicabilityBasedInspecti
             }
         }
 
+        private fun createElvisExpression(element: KtIfExpression, data: Data, factory: KtPsiFactory): KtBinaryExpression {
+            val (initializer, declaration, ifNullExpr, _) = data
+            val margin = CodeStyle.getSettings(element.containingKtFile).defaultRightMargin
+            val declarationTextLength = declaration.text.split("\n").lastOrNull()?.trim()?.length ?: 0
+            val pattern = elvisPattern(declarationTextLength + ifNullExpr.textLength + 5 >= margin || element.then?.hasComments() == true)
+            return factory.createExpressionByPattern(pattern, initializer, ifNullExpr) as KtBinaryExpression
+        }
+
         private fun calcData(ifExpression: KtIfExpression): Data? {
             if (ifExpression.`else` != null) return null
 

idea/testData/inspectionsLocal/foldInitializerAndIfToElvis/ComplexExpression.kt

@@ -0,0 +1,12 @@
+// PROBLEM: none
+private fun foo(arg: Any): Int {
+    val x =
+        if (arg is String)
+            (arg.length + 1)
+        else
+            arg.hashCode()
+
+    if (<caret>x == null) return 0
+
+    return x
+}

idea/tests/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java

@@ -4814,6 +4814,11 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
             runTest("idea/testData/inspectionsLocal/foldInitializerAndIfToElvis/Comments2.kt");
         }
 
+        @TestMetadata("ComplexExpression.kt")
+        public void testComplexExpression() throws Exception {
+            runTest("idea/testData/inspectionsLocal/foldInitializerAndIfToElvis/ComplexExpression.kt");
+        }
+
         @TestMetadata("Continue.kt")
         public void testContinue() throws Exception {
             runTest("idea/testData/inspectionsLocal/foldInitializerAndIfToElvis/Continue.kt");