Move Es6RewriteClassExtends and Es6ExtractClasses passes above RewriteClassMembers in the transpilation order.

This change allows RewriteClassMembers to correctly transpile public fields when the class is located in a location that doesn't easily allow multiple statements such as declaring a class inside of a new call (e.g. `new (class Foo { static x; })()`).

For that to work Es6ExtractClasses was also changed to transpile all classes
instead of only transpiling when it detects that Es6 classes are not supported for the output language.

PiperOrigin-RevId: 552519883

Author: Closure Team

src/com/google/javascript/jscomp/Es6ExtractClasses.java

@@ -24,7 +24,6 @@
 import com.google.javascript.jscomp.ExpressionDecomposer.DecompositionType;
 import com.google.javascript.jscomp.colors.StandardColors;
 import com.google.javascript.jscomp.deps.ModuleNames;
-import com.google.javascript.jscomp.parsing.parser.FeatureSet;
 import com.google.javascript.jscomp.parsing.parser.FeatureSet.Feature;
 import com.google.javascript.rhino.IR;
 import com.google.javascript.rhino.JSDocInfo;
@@ -67,7 +66,6 @@ public final class Es6ExtractClasses extends NodeTraversal.AbstractPostOrderCall
   private final AstFactory astFactory;
   private final ExpressionDecomposer expressionDecomposer;
   private int classDeclVarCounter = 0;
-  private static final FeatureSet features = FeatureSet.BARE_MINIMUM.with(Feature.CLASSES);
 
   Es6ExtractClasses(AbstractCompiler compiler) {
     this.compiler = compiler;
@@ -83,10 +81,8 @@ public void process(Node externs, Node root) {
       // TODO(b/197349249): Remove once b/197349249 is fixed.
       NodeTraversal.traverse(compiler, root, new NormalizeArrows());
     }
-    TranspilationPasses.processTranspile(
-        compiler, externs, features, this, new SelfReferenceRewriter());
-    TranspilationPasses.processTranspile(
-        compiler, root, features, this, new SelfReferenceRewriter());
+    NodeTraversal.traverseRoots(compiler, this, externs, root);
+    NodeTraversal.traverseRoots(compiler, new SelfReferenceRewriter(), externs, root);
   }
 
   @Override

src/com/google/javascript/jscomp/TranspilationPasses.java

@@ -78,6 +78,16 @@ public static void addEarlyOptimizationTranspilationPasses(
               "markEs2022FeaturesNotRequiringTranspilationAsRemoved", Feature.REGEXP_FLAG_D));
     }
 
+    if (options.needsTranspilationOf(Feature.PUBLIC_CLASS_FIELDS)
+        || options.needsTranspilationOf(Feature.CLASS_STATIC_BLOCK)
+        || options.needsTranspilationOf(Feature.CLASSES)) {
+      // Make sure that a variable is created to hold every class definition.
+      // This allows us to add static properties and methods by adding properties
+      // to that variable.
+      passes.maybeAdd(es6RewriteClassExtends);
+      passes.maybeAdd(es6ExtractClasses);
+    }
+
     if (options.needsTranspilationOf(Feature.PUBLIC_CLASS_FIELDS)
         || options.needsTranspilationOf(Feature.CLASS_STATIC_BLOCK)) {
       passes.maybeAdd(rewriteClassMembers);
@@ -173,7 +183,6 @@ public static void addEarlyOptimizationTranspilationPasses(
       passes.maybeAdd(es6NormalizeShorthandProperties);
     }
     if (options.needsTranspilationOf(Feature.CLASSES)) {
-      passes.maybeAdd(es6RewriteClassExtends);
       passes.maybeAdd(es6ConvertSuper);
     }
     if (options.needsTranspilationFrom(
@@ -190,7 +199,6 @@ public static void addEarlyOptimizationTranspilationPasses(
       passes.maybeAdd(es6RewriteArrowFunction);
     }
     if (options.needsTranspilationOf(Feature.CLASSES)) {
-      passes.maybeAdd(es6ExtractClasses);
       passes.maybeAdd(es6RewriteClass);
     }
     if (options.needsTranspilationFrom(

test/com/google/javascript/jscomp/TranspileOnlyIntegrationTest.java renamed to test/com/google/javascript/jscomp/integration/TranspileOnlyIntegrationTest.java

@@ -13,10 +13,11 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.google.javascript.jscomp;
+package com.google.javascript.jscomp.integration;
 
-import static com.google.common.truth.Truth.assertThat;
+import static com.google.javascript.jscomp.base.JSCompStrings.lines;
 
+import com.google.javascript.jscomp.CompilerOptions;
 import com.google.javascript.jscomp.CompilerOptions.LanguageMode;
 import org.jspecify.nullness.Nullable;
 import org.junit.Before;
@@ -30,14 +31,12 @@
  * <p>This class actually tests several transpilation passes together.
  */
 @RunWith(JUnit4.class)
-public final class TranspileOnlyIntegrationTest {
+public final class TranspileOnlyIntegrationTest extends IntegrationTestCase {
 
-  private @Nullable Compiler compiler = null;
   private @Nullable CompilerOptions options = null;
 
   @Before
   public void init() {
-    compiler = new Compiler();
     options = new CompilerOptions();
     options.setLanguage(LanguageMode.ECMASCRIPT_NEXT);
     options.setSkipNonTranspilationPasses(true);
@@ -47,21 +46,41 @@ public void init() {
   @Test
   public void esModuleNoTranspilationForSameLanguageLevel() {
     String js = "export default function fn(){};";
-    test(js, js);
+    test(options, js, js);
   }
 
   @Test
   public void esModuleTranspilationForDifferentLanguageLevel() {
     String js = "export default function fn() {}";
     String transpiled =
-        "function fn$$module$in(){}var module$in={};module$in.default=fn$$module$in;";
+        "function fn$$module$i0(){}var module$i0={};module$i0.default=fn$$module$i0;";
     options.setLanguageOut(LanguageMode.ECMASCRIPT_2020);
-    test(js, transpiled);
+    test(options, js, transpiled);
   }
 
-  private void test(String js, String transpiled) {
-    compiler.compile(SourceFile.fromCode("ext.js", ""), SourceFile.fromCode("in.js", js), options);
-    assertThat(compiler.getErrors()).isEmpty();
-    assertThat(compiler.toSource()).isEqualTo(transpiled);
+  // Added when moving Es6ExtractClasses before RewriteClassMembers and fixing an issue with
+  // not rewriting extends
+  @Test
+  public void testClassExtendsAnonymousClass() {
+    options.setLanguage(LanguageMode.UNSTABLE);
+    options.setLanguageOut(LanguageMode.ECMASCRIPT5);
+    test(
+        options,
+        lines(
+            "class Bar {}", //
+            "class Foo extends (class extends Bar {}) {",
+            "  static x;",
+            "}"),
+        lines(
+            "var Bar = function() {};",
+            "var i0$classextends$var0 = function() {",
+            "  Bar.apply(this, arguments)",
+            "};",
+            "$jscomp.inherits(i0$classextends$var0, Bar);",
+            "var Foo = function() {",
+            "  i0$classextends$var0.apply(this, arguments)",
+            "};",
+            "$jscomp.inherits(Foo, i0$classextends$var0);",
+            "Foo.x;"));
   }
 }