Fix incorrect change scope reporting in Es6RewriteDestructuring & IsolatePolyfills

Es6RewriteDestructuring was reporting nested scopes were changed, when they were not; IsolatedPolyfills was failing to report adding a new temporary variable to the initial script.

PiperOrigin-RevId: 830553255

Author: lauraharker

src/com/google/javascript/jscomp/Es6RewriteDestructuring.java

@@ -889,7 +889,6 @@ private void visitDestructuringPatternInVanillaForInnerVars(NodeTraversal t, Nod
     }
 
     this.compiler.reportChangeToEnclosingScope(insertionPoint);
-    NodeUtil.markNewScopesChanged(insertionPoint, compiler);
   }
 
   /** for (const [a, b, c] of arr) */

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

@@ -304,6 +304,7 @@ private Node createTempName(Node srcref) {
       isTempVarInitialized = true;
       Node decl = IR.var(IR.name(POLYFILL_TEMP)).srcrefTree(srcref);
       compiler.getNodeForCodeInsertion(null).addChildToFront(decl);
+      compiler.reportChangeToEnclosingScope(decl);
     }
     // The same temporary variable is always used for every polyfill invocation. This is believed
     // to be safe and makes the code easier to generate and smaller. There's a change it will make
@@ -354,7 +355,7 @@ private void cleanUpJscompLookupPolyfilledValue() {
 
     Scope syntheticCodeScope =
         new SyntacticScopeCreator(compiler)
-            .createScope(compiler.getNodeForCodeInsertion(/* module= */ null), /* parent= */ null);
+            .createScope(compiler.getNodeForCodeInsertion(/* chunk= */ null), /* parent= */ null);
     Var syntheticVar = syntheticCodeScope.getVar(jscompLookupMethod.getString());
     // Don't error if we can't find a definition for jscompLookupMethod. It's possible that we are
     // running in transpileOnly mode and are not injecting runtime libraries.

test/com/google/javascript/jscomp/Es6RewriteDestructuringTest.java

@@ -80,6 +80,37 @@ protected CompilerPass getProcessor(Compiler compiler) {
         .build();
   }
 
+  @Test
+  public void testForLoopInitializer_let_accessedInClosure() {
+    test(
+        """
+        const aClosures = [];
+        const bClosures = [];
+        for (let a = 0, [b, c] = [a, 3]; b < c; a--, b++) {
+          aClosures.push(() => a);
+          bClosures.push(() => b);
+        }
+        """,
+        """
+        const aClosures = [];
+        const bClosures = [];
+        for (let a = 0, b, c, $jscomp$destructuring$var0$unused = (() => {
+          let $jscomp$destructuring$var1 = [a, 3];
+          var $jscomp$destructuring$var2 = (0,$jscomp.makeIterator)($jscomp$destructuring$var1);
+          b = $jscomp$destructuring$var2.next().value;
+          c = $jscomp$destructuring$var2.next().value;
+          return $jscomp$destructuring$var1;
+        })(); b < c; a--, b++) {
+          aClosures.push(() => {
+            return a;
+          });
+          bClosures.push(() => {
+            return b;
+          });
+        }
+        """);
+  }
+
   @Test
   public void testObjectDestructuring_forLoopInitializer_doesNotCrash() {
     test(

test/com/google/javascript/jscomp/IsolatePolyfillsTest.java

@@ -71,7 +71,7 @@ protected CompilerPass getProcessor(Compiler compiler) {
           .getSynthesizedExternsInput()
           .getAstRoot(compiler)
           .addChildToBack(IR.var(IR.name("$jscomp$lookupPolyfilledValue")));
-      addPolyfillInjection(compiler.getNodeForCodeInsertion(/* module= */ null), compiler);
+      addPolyfillInjection(compiler.getNodeForCodeInsertion(/* chunk= */ null), compiler);
       new IsolatePolyfills(compiler, Polyfills.fromTable(Joiner.on("\n").join(polyfillTable)))
           .process(externs, root);
     };
@@ -479,4 +479,26 @@ public void testJscompLookupPolyfillKeptIfUsed() {
           .call($jscomp$polyfillTmp, cb);
         """);
   }
+
+  @Test
+  public void testPolyfilTemp_multipleFiles_insertedInFirstFile() {
+    // Regression test for failure to report code change when adding "var $jscomp$polyfillTmp;"
+    // Don't call addLibrary() for this test: it reports a code change regardless & make the
+    // test incorrectly pass.
+    polyfillTable.add("String.prototype.endsWith es6 es5 es6/string/endswith");
+    setLanguage(ES6, ES5);
+
+    test(
+        srcs("$jscomp.polyfill('String.prototype.endsWith', 'es6', 'es5');", "x().endsWith(y);"),
+        expected(
+            """
+            var $jscomp$polyfillTmp;
+            $jscomp.polyfill('String.prototype.endsWith', 'es6', 'es5');
+            """,
+            """
+            ($jscomp$polyfillTmp = x(),
+              $jscomp$lookupPolyfilledValue($jscomp$polyfillTmp, 'endsWith'))
+                  .call($jscomp$polyfillTmp, y);
+            """));
+  }
 }