chore: remove unused break statements from inlined functions bodies.

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsStatementTransformer.kt

@@ -5,7 +5,7 @@
 
 package org.jetbrains.kotlin.ir.backend.js.transformers.irToJs
 
-import org.jetbrains.kotlin.backend.common.compilationException
+import org.jetbrains.kotlin.ir.backend.js.utils.isTheLastReturnStatementIn
 import org.jetbrains.kotlin.ir.backend.js.JsIrBackendContext
 import org.jetbrains.kotlin.ir.backend.js.utils.JsGenerationContext
 import org.jetbrains.kotlin.ir.backend.js.utils.emptyScope
@@ -94,7 +94,11 @@ class IrElementToJsStatementTransformer : BaseIrElementToJsNodeTransformer<JsSta
         val lastStatementTransformer: (JsExpression) -> JsStatement =
             if (targetSymbol is IrReturnableBlockSymbol) {
                 // TODO assert that value is Unit?
-                { JsBreak(context.getNameForReturnableBlock(targetSymbol.owner)!!.makeRef()) }
+                {
+                    context.getNameForReturnableBlock(targetSymbol.owner)
+                    .takeIf { !expression.isTheLastReturnStatementIn(targetSymbol) }
+                    ?.run { JsBreak(makeRef()) } ?: JsEmpty
+                }
             } else {
                 { JsReturn(it) }
             }

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/utils/IrJsUtils.kt

@@ -9,6 +9,8 @@ import org.jetbrains.kotlin.descriptors.isInterface
 import org.jetbrains.kotlin.descriptors.isClass
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrDeclaration
+import org.jetbrains.kotlin.ir.expressions.IrReturn
+import org.jetbrains.kotlin.ir.symbols.IrReturnableBlockSymbol
 import org.jetbrains.kotlin.ir.util.parentClassOrNull
 
 fun IrDeclaration.isExportedMember() =
@@ -21,4 +23,8 @@ fun IrDeclaration?.isExportedInterface() =
     this is IrClass && kind.isInterface && isJsExport()
 
 fun IrDeclaration.isExportedInterfaceMember() =
-    parentClassOrNull.isExportedInterface()
+    parentClassOrNull.isExportedInterface()
+
+fun IrReturn.isTheLastReturnStatementIn(target: IrReturnableBlockSymbol): Boolean {
+    return target.owner.statements.lastOrNull() === this
+}

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/utils/NameTables.kt

@@ -339,7 +339,7 @@ class LocalNameGenerator(val variableNames: NameTable<IrDeclaration>) : IrElemen
 
     override fun visitReturn(expression: IrReturn) {
         val targetSymbol = expression.returnTargetSymbol
-        if (targetSymbol is IrReturnableBlockSymbol) {
+        if (targetSymbol is IrReturnableBlockSymbol && !expression.isTheLastReturnStatementIn(targetSymbol)) {
             persistReturnableBlockName(SYNTHETIC_BLOCK_LABEL, targetSymbol.owner)
         }
 

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/BoxJsTestGenerated.java

@@ -4844,6 +4844,12 @@ public class BoxJsTestGenerated extends AbstractBoxJsTest {
             runTest("js/js.translator/testData/box/inline/lambdaReassignmentWithCapture.kt");
         }
 
+        @Test
+        @TestMetadata("lastLabeledReturn.kt")
+        public void testLastLabeledReturn() throws Exception {
+            runTest("js/js.translator/testData/box/inline/lastLabeledReturn.kt");
+        }
+
         @Test
         @TestMetadata("localDeclarationsClash.kt")
         public void testLocalDeclarationsClash() throws Exception {

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrBoxJsTestGenerated.java

@@ -5222,6 +5222,12 @@ public class IrBoxJsTestGenerated extends AbstractIrBoxJsTest {
             runTest("js/js.translator/testData/box/inline/lambdaReassignmentWithCapture.kt");
         }
 
+        @Test
+        @TestMetadata("lastLabeledReturn.kt")
+        public void testLastLabeledReturn() throws Exception {
+            runTest("js/js.translator/testData/box/inline/lastLabeledReturn.kt");
+        }
+
         @Test
         @TestMetadata("localDeclarationsClash.kt")
         public void testLocalDeclarationsClash() throws Exception {

js/js.translator/testData/box/inline/lastLabeledReturn.kt

@@ -0,0 +1,12 @@
+inline fun foo(l: () -> Unit) { l() }
+inline fun bar(l: () -> Unit) { l() }
+
+fun box(): String {
+    foo {
+        bar {
+            return@foo;
+        }
+        return "Failed: labeled return was not added"
+    }
+    return "OK"
+}