[kotlin] KTIJ-22055 SuspiciousCascadingIfInspection: support safe call

KTIJ-22055
IJ-CR-165301

GitOrigin-RevId: 7001d847604806947e6ccd32db7858f4038c1b1f

plugins/kotlin/code-insight/inspections-k2/src/org/jetbrains/kotlin/idea/k2/codeinsight/inspections/SuspiciousCascadingIfInspection.kt

@@ -30,7 +30,7 @@ internal class SuspiciousCascadingIfInspection : KotlinApplicableInspectionBase<
         if (element.parent.node.elementType == KtNodeTypes.ELSE) return false
 
         val candidateExpression = when (val lastElseBranch = element.findLastElseBranch()) {
-            is KtDotQualifiedExpression -> lastElseBranch.receiverExpression
+            is KtQualifiedExpression -> lastElseBranch.receiverExpression
             is KtBinaryExpression -> lastElseBranch.left
             else -> null
         }
@@ -89,12 +89,13 @@ private class ConvertIfToWhenFix : KotlinModCommandQuickFix<KtIfExpression>() {
                 whenExpr.replace(outerBinaryExpr)
             }
 
-            is KtDotQualifiedExpression -> {
+            is KtQualifiedExpression -> {
                 val selectorText = lastElseBranch.selectorExpression?.text ?: ""
                 val nestedIf = lastElseBranch.receiverExpression
                 lastElseBranch.replace(nestedIf)
                 val whenExpr = convertIfToWhen(element, updater)
-                val outerQualifiedExpr = psiFactory.createExpressionByPattern("$0.$1", whenExpr, selectorText)
+                val operator = lastElseBranch.operationSign.value // . or ?.
+                val outerQualifiedExpr = psiFactory.createExpressionByPattern("$0$1$2", whenExpr, operator, selectorText)
                 whenExpr.replace(outerQualifiedExpr)
             }
         }

plugins/kotlin/code-insight/inspections-k2/tests/test/org/jetbrains/kotlin/idea/k2/inspections/tests/K2LocalInspectionTestGenerated.java

@@ -4273,6 +4273,11 @@ public abstract class K2LocalInspectionTestGenerated extends AbstractK2LocalInsp
             runTest("../../../idea/tests/testData/inspectionsLocal/suspiciousCascadingIf/ifElseBlockCascadeQualifiedExprAddBraces.kt");
         }
 
+        @TestMetadata("ifElseBlockCascadeSafeCallExpr.kt")
+        public void testIfElseBlockCascadeSafeCallExpr() throws Exception {
+            runTest("../../../idea/tests/testData/inspectionsLocal/suspiciousCascadingIf/ifElseBlockCascadeSafeCallExpr.kt");
+        }
+
         @TestMetadata("ifElseBlockQualifiedExpr.kt")
         public void testIfElseBlockQualifiedExpr() throws Exception {
             runTest("../../../idea/tests/testData/inspectionsLocal/suspiciousCascadingIf/ifElseBlockQualifiedExpr.kt");

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

@@ -15584,6 +15584,11 @@ public abstract class LocalInspectionTestGenerated extends AbstractLocalInspecti
             runTest("testData/inspectionsLocal/suspiciousCascadingIf/ifElseBlockCascadeQualifiedExprAddBraces.kt");
         }
 
+        @TestMetadata("ifElseBlockCascadeSafeCallExpr.kt")
+        public void testIfElseBlockCascadeSafeCallExpr() throws Exception {
+            runTest("testData/inspectionsLocal/suspiciousCascadingIf/ifElseBlockCascadeSafeCallExpr.kt");
+        }
+
         @TestMetadata("ifElseBlockQualifiedExpr.kt")
         public void testIfElseBlockQualifiedExpr() throws Exception {
             runTest("testData/inspectionsLocal/suspiciousCascadingIf/ifElseBlockQualifiedExpr.kt");

plugins/kotlin/idea/tests/testData/inspectionsLocal/suspiciousCascadingIf/ifElseBlockCascadeSafeCallExpr.kt

@@ -0,0 +1,13 @@
+// PROBLEM: Suspicious cascading 'if' expression
+// FIX: Replace 'if' with 'when' (changes semantics)
+// IGNORE_K1
+// WITH_STDLIB
+fun test() {
+    <caret>if (true) {
+        1
+    } else if (true) {
+        2
+    } else {
+        3
+    }?.let { print(it) }
+}

plugins/kotlin/idea/tests/testData/inspectionsLocal/suspiciousCascadingIf/ifElseBlockCascadeSafeCallExpr.kt.after

@@ -0,0 +1,19 @@
+// PROBLEM: Suspicious cascading 'if' expression
+// FIX: Replace 'if' with 'when' (changes semantics)
+// IGNORE_K1
+// WITH_STDLIB
+fun test() {
+    when {
+        true -> {
+            1
+        }
+
+        true -> {
+            2
+        }
+
+        else -> {
+            3
+        }
+    }?.let { print(it) }
+}