[babel 8] Do not skip requeued paths (#13291)

packages/babel-plugin-transform-block-scoping/src/tdz.js

@@ -27,6 +27,8 @@ function isReference(node, scope, state) {
   return scope.getBindingIdentifier(node.name) === declared;
 }
 
+const visitedMaybeTDZNodes = new WeakSet();
+
 export const visitor = {
   ReferencedIdentifier(path, state) {
     if (!state.tdzEnabled) return;
@@ -44,13 +46,15 @@ export const visitor = {
     if (status === "outside") return;
 
     if (status === "maybe") {
+      if (visitedMaybeTDZNodes.has(node)) {
+        return;
+      }
+      visitedMaybeTDZNodes.add(node);
       const assert = buildTDZAssert(node, state);
 
       // add tdzThis to parent variable declarator so it's exploded
       bindingPath.parent._tdzThis = true;
 
-      path.skip();
-
       if (path.parentPath.isUpdateExpression()) {
         if (parent._ignoreBlockScopingTDZ) return;
         path.parentPath.replaceWith(t.sequenceExpression([assert, parent]));

packages/babel-traverse/src/path/context.ts

@@ -251,13 +251,11 @@ export function setKey(this: NodePath, key) {
 export function requeue(this: NodePath, pathToQueue = this) {
   if (pathToQueue.removed) return;
 
-  // TODO: Uncomment in Babel 8. If a path is skipped, and then replaced with a
+  // If a path is skipped, and then replaced with a
   // new one, the new one shouldn't probably be skipped.
-  // Note that this currently causes an infinite loop because of
-  // packages/babel-plugin-transform-block-scoping/src/tdz.js#L52-L59
-  // (b5b8055cc00756f94bf71deb45f288738520ee3c)
-  //
-  // pathToQueue.shouldSkip = false;
+  if (process.env.BABEL_8_BREAKING) {
+    pathToQueue.shouldSkip = false;
+  }
 
   // TODO(loganfsmyth): This should be switched back to queue in parent contexts
   // automatically once #2892 and #4135 have been resolved. See #4140.