JS: fix translation of && and || operators when their RHS declare temporary variables. See KT-16350

Author: Alexey Andreev

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/BoxJsTestGenerated.java

@@ -2005,6 +2005,12 @@ public void testAndAndWithSideEffect() throws Exception {
                 doTest(fileName);
             }
 
+            @TestMetadata("andAndWithTmpVarRhs.kt")
+            public void testAndAndWithTmpVarRhs() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("js/js.translator/testData/box/expression/evaluationOrder/andAndWithTmpVarRhs.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("assignToArrayElementWithSideEffect.kt")
             public void testAssignToArrayElementWithSideEffect() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("js/js.translator/testData/box/expression/evaluationOrder/assignToArrayElementWithSideEffect.kt");

js/js.translator/src/org/jetbrains/kotlin/js/translate/operation/BinaryOperationTranslator.java

@@ -21,6 +21,7 @@
 import org.jetbrains.kotlin.descriptors.CallableDescriptor;
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor;
 import org.jetbrains.kotlin.js.backend.ast.*;
+import org.jetbrains.kotlin.js.backend.ast.metadata.MetadataProperties;
 import org.jetbrains.kotlin.js.translate.callTranslator.CallTranslator;
 import org.jetbrains.kotlin.js.translate.context.TranslationContext;
 import org.jetbrains.kotlin.js.translate.general.AbstractTranslator;
@@ -202,10 +203,12 @@ else if (OperatorConventions.IDENTITY_EQUALS_OPERATIONS.contains(operationToken)
             if (rightExpression instanceof JsNameRef) {
                 result = rightExpression; // Reuse tmp variable
             } else {
-                result = context().defineTemporary(rightExpression);
+                result = context().declareTemporary(null).reference();
+                rightBlock.getStatements().add(JsAstUtils.asSyntheticStatement(JsAstUtils.assignment(result, rightExpression)));
             }
-            JsStatement assignmentStatement = JsAstUtils.assignment(result, literalResult).makeStmt();
+            JsStatement assignmentStatement = JsAstUtils.asSyntheticStatement(JsAstUtils.assignment(result, literalResult));
             ifStatement = JsAstUtils.newJsIf(leftExpression, rightBlock, assignmentStatement);
+            MetadataProperties.setSynthetic(ifStatement, true);
         }
         else {
             ifStatement = JsAstUtils.newJsIf(leftExpression, rightBlock);

js/js.translator/testData/box/expression/evaluationOrder/andAndWithTmpVarRhs.kt

@@ -0,0 +1,8 @@
+fun foo(arg: Any): Boolean {
+    return arg == "x"
+}
+
+fun box(): String {
+    val values = listOf(null, "x")
+    return if (values[0] == null && foo(values[1]!!)) "OK" else "fail"
+}