#EA-79158 Fix translation of empty 'when' statement

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

@@ -133,4 +133,8 @@ public final class WhenTest extends AbstractExpressionTest {
     public void testWhenStatementWithRangeClause() throws Exception {
         checkFooBoxIsOk();
     }
+
+    public void testEmpty() throws Exception {
+        checkFooBoxIsOk();
+    }
 }

js/js.translator/src/org/jetbrains/kotlin/js/translate/expression/WhenTranslator.java

@@ -67,7 +67,7 @@ public final class WhenTranslator extends AbstractTranslator {
         }
     }
 
-    private JsStatement translate() {
+    private JsNode translate() {
         if (expressionToMatch != null && JsAstUtils.isEmptyExpression(expressionToMatch)) {
             return JsEmpty.INSTANCE;
         }
@@ -100,7 +100,7 @@ public final class WhenTranslator extends AbstractTranslator {
                 currentIf = nextIf;
             }
         }
-        return resultIf;
+        return resultIf != null ? resultIf : context().getEmptyExpression();
     }
 
     @NotNull

js/js.translator/testData/expression/when/cases/empty.kt

@@ -0,0 +1,6 @@
+package foo
+
+fun box(): String {
+    when {}
+    return "OK"
+}