"Lift return / assignment": do not suggest for else arguments

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

@@ -20,6 +20,7 @@ import com.intellij.codeInspection.*
 import com.intellij.openapi.project.Project
 import com.intellij.psi.PsiElement
 import org.jetbrains.kotlin.idea.intentions.branchedTransformations.BranchedFoldingUtils
+import org.jetbrains.kotlin.idea.intentions.branchedTransformations.isIfBranch
 import org.jetbrains.kotlin.idea.intentions.branchedTransformations.lineCount
 import org.jetbrains.kotlin.psi.KtExpression
 import org.jetbrains.kotlin.psi.KtIfExpression
@@ -33,6 +34,8 @@ class LiftReturnOrAssignmentInspection : AbstractKotlinInspection() {
             object : KtVisitorVoid() {
                 private fun visitIfOrWhen(expression: KtExpression, keyword: PsiElement) {
                     if (expression.lineCount() > LINES_LIMIT) return
+                    if (expression.isIfBranch()) return
+
                     val returnNumber = BranchedFoldingUtils.getFoldableReturnNumber(expression)
                     if (returnNumber > 0) {
                         holder.registerProblem(

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

@@ -264,3 +264,11 @@ internal fun KtExpression.lineCount(): Int {
 }
 
 internal fun KtExpression.isOneLiner(): Boolean = lineCount() == 1
+
+internal fun KtExpression.isIfBranch(): Boolean {
+    if (parent is KtContainerNodeForControlStructureBody) {
+        val grandParent = parent.parent
+        if (grandParent is KtIfExpression && grandParent.`else` == this) return true
+    }
+    return false
+}

idea/testData/inspectionsLocal/liftOut/ifToAssignment/elseIfOnly.kt

@@ -0,0 +1,15 @@
+// PROBLEM: none
+
+fun foo(a: Boolean, b: Boolean): String {
+    var res = ""
+    if (a) {
+
+    }
+    else <caret>if (b) {
+        res += "b"
+    }
+    else {
+        res += "!b"
+    }
+    return res
+}

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

@@ -418,6 +418,12 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("elseIfOnly.kt")
+            public void testElseIfOnly() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/liftOut/ifToAssignment/elseIfOnly.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("ifElseIf.kt")
             public void testIfElseIf() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/liftOut/ifToAssignment/ifElseIf.kt");