From 1ab78dffe5c932d4d0fadb8cdc3a4f668c7d08d1 Mon Sep 17 00:00:00 2001
From: Alexey Andreev <Alexey.Andreev@jetbrains.com>
Date: Wed, 21 Dec 2016 17:22:43 +0300
Subject: [PATCH] JS: fix translation of `for` statement when either `next` or
 `hasNext` method translates to multiple statements. Fix KT-15367

---
 .../codegen/box/coroutines/asyncIterator.kt   |  1 -
 .../semantics/JsCodegenBoxTestGenerated.java  |  6 ++++
 .../js/translate/expression/LoopTranslator.kt | 34 ++++++++++++++-----
 3 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/compiler/testData/codegen/box/coroutines/asyncIterator.kt b/compiler/testData/codegen/box/coroutines/asyncIterator.kt
index bb986cb6266..027eeb08845 100644
--- a/compiler/testData/codegen/box/coroutines/asyncIterator.kt
+++ b/compiler/testData/codegen/box/coroutines/asyncIterator.kt
@@ -1,6 +1,5 @@
 // WITH_RUNTIME
 // WITH_COROUTINES
-// TARGET_BACKEND: JVM
 import kotlin.coroutines.*
 
 interface AsyncGenerator<in T> {
diff --git a/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java b/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
index 03ca841e255..98d48f87f9d 100644
--- a/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
+++ b/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
@@ -5298,6 +5298,12 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/codegen/box/coroutines"), Pattern.compile("^(.+)\\.kt$"), TargetBackend.JS, true);
         }
 
+        @TestMetadata("asyncIterator.kt")
+        public void testAsyncIterator() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/coroutines/asyncIterator.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("await.kt")
         public void testAwait() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/coroutines/await.kt");
diff --git a/js/js.translator/src/org/jetbrains/kotlin/js/translate/expression/LoopTranslator.kt b/js/js.translator/src/org/jetbrains/kotlin/js/translate/expression/LoopTranslator.kt
index 2faebf8bb6b..2ee1c7d4052 100644
--- a/js/js.translator/src/org/jetbrains/kotlin/js/translate/expression/LoopTranslator.kt
+++ b/js/js.translator/src/org/jetbrains/kotlin/js/translate/expression/LoopTranslator.kt
@@ -179,25 +179,43 @@ fun translateForExpression(expression: KtForExpression, context: TranslationCont
 
     fun translateForOverIterator(): JsStatement {
 
-        fun translateMethodInvocation(receiver: JsExpression?, resolvedCall: ResolvedCall<FunctionDescriptor>): JsExpression =
-                CallTranslator.translate(context, resolvedCall, receiver)
+        fun translateMethodInvocation(
+                receiver: JsExpression?,
+                resolvedCall: ResolvedCall<FunctionDescriptor>,
+                block: JsBlock
+        ): JsExpression = CallTranslator.translate(context.innerBlock(block), resolvedCall, receiver)
 
         fun iteratorMethodInvocation(): JsExpression {
             val range = Translation.translateAsExpression(loopRange, context)
             val resolvedCall = getIteratorFunction(context.bindingContext(), loopRange)
-            return translateMethodInvocation(range, resolvedCall)
+            return CallTranslator.translate(context, resolvedCall, range)
         }
 
         val iteratorVar = context.defineTemporary(iteratorMethodInvocation())
 
-        fun hasNextMethodInvocation(): JsExpression {
+        fun hasNextMethodInvocation(block: JsBlock): JsExpression {
             val resolvedCall = getHasNextCallable(context.bindingContext(), loopRange)
-            return translateMethodInvocation(iteratorVar, resolvedCall)
+            return translateMethodInvocation(iteratorVar, resolvedCall, block)
         }
 
-        val nextInvoke = translateMethodInvocation(iteratorVar, getNextFunction(context.bindingContext(), loopRange))
-        val body = translateBody(nextInvoke)
-        return JsWhile(hasNextMethodInvocation(), body ?: nextInvoke.makeStmt())
+        val hasNextBlock = JsBlock()
+        val hasNextInvocation = hasNextMethodInvocation(hasNextBlock)
+
+        val nextBlock = JsBlock()
+        val nextInvoke = translateMethodInvocation(iteratorVar, getNextFunction(context.bindingContext(), loopRange), nextBlock)
+
+        val bodyStatements = mutableListOf<JsStatement>()
+        val exitCondition = if (hasNextBlock.isEmpty) {
+            hasNextInvocation
+        }
+        else {
+            bodyStatements += hasNextBlock.statements
+            bodyStatements += JsIf(notOptimized(hasNextInvocation), JsBreak())
+            JsLiteral.TRUE
+        }
+        bodyStatements += nextBlock.statements
+        bodyStatements += translateBody(nextInvoke)?.let(::flattenStatement).orEmpty()
+        return JsWhile(exitCondition, bodyStatements.singleOrNull() ?: JsBlock(bodyStatements))
     }
 
     return when {