js_printer: re-wrap delete of folded import/cjs-export identifier

src/js_printer/lib.rs

@@ -1215,7 +1215,14 @@
 fn is_identifier_or_numeric_constant_or_property_access(expr: &js_ast::Expr) -> bool {
     use js_ast::ExprData;
     match &expr.data {
         ExprData::EIdentifier(_) | ExprData::EDot(_) | ExprData::EIndex(_) => true,
+        // These are produced by the visit pass (namespace-import rewrite, cjs2esm,
+        // `module.exports`/`import.meta.hot` inlining) and print as a bare identifier
+        // or a property access. Without the `(0, ...)` wrap the printed `delete` sees
+        // a Reference and its result/effect differ from the source.
+        ExprData::EImportIdentifier(_)
+        | ExprData::ECommonjsExportIdentifier(_)
+        | ExprData::ESpecial(_) => true,
         ExprData::ENumber(e) => e.value().is_infinite() || e.value().is_nan(),
         _ => false,
     }

test/bundler/bundler_cjs2esm.test.ts

@@ -392,6 +392,37 @@ describe("bundler", () => {
       stdout: '[[{"xyz":456},456],[{"xyz":123},123],[{"xyz":456},456],[{"xyz":123},123]]',
     },
   });
+  // `delete (null ?? exports.a)` evaluates to a value, so the result is `true`
+  // with no effect on the property. Under cjs2esm, `exports.a` is rewritten to
+  // an `ECommonjsExportIdentifier`; the printer has to re-wrap it as `(0, ...)`
+  // so `delete` still sees a value instead of the hoisted binding.
+  itBundled("cjs2esm/DeleteFoldedExportsPropertyRef", {
+    files: {
+      "/entry.js": /* js */ `
+        exports.a = 1;
+        console.log(delete (null ?? exports.a), exports.a);
+        console.log(delete (0, exports.a), exports.a);
+      `,
+    },
+    onAfterBundle: api => {
+      const code = api.readFile("out.js");
+      expect(code).not.toMatch(/^[^"]*delete\s+\$a\b/m);
+    },
+    run: { stdout: "true 1\ntrue 1" },
+  });
+  itBundled("cjs2esm/DeleteFoldedExportsPropertyRefConsumer", {
+    files: {
+      "/entry.js": /* js */ `
+        import { a } from "./lib.js";
+        console.log(a);
+      `,
+      "/lib.js": /* js */ `
+        exports.a = 1;
+        console.log(delete (null ?? exports.a), exports.a);
+      `,
+    },
+    run: { stdout: "true 1\n1" },
+  });
   // https://github.com/oven-sh/bun/issues/4565
   // `exports.x = ...` as the unbraced body of if/while/do/else must not be
   // converted to `var $x = ...; export { $x as x };` because `export` is only

test/bundler/bundler_edgecase.test.ts

@@ -2858,6 +2858,61 @@ describe("bundler", () => {
       expect(out).not.toContain("require_foo\u2014bar");
     },
   });
+  // `delete (null ?? ns.x)` evaluates its operand to a value, so the result is
+  // `true` with no side effect. When bundling rewrites `ns.x` to the local
+  // binding (EImportIdentifier) after folding `??`, the printer must re-wrap
+  // the operand so `delete` still sees a value instead of the binding itself.
+  // Without the wrap the output is `delete x`, a strict-mode SyntaxError.
+  itBundled("edgecase/DeleteFoldedNamespacePropertyRef", {
+    files: {
+      "/entry.js": /* js */ `
+        import * as ns from "./m.js";
+        console.log(delete (null ?? ns.x), ns.x);
+        console.log(delete (0, ns.x), ns.x);
+        console.log(delete (true ? ns.x : 0), ns.x);
+      `,
+      "/m.js": /* js */ `
+        export let x = 1;
+      `,
+    },
+    onAfterBundle: api => {
+      const code = api.readFile("out.js");
+      expect(code).not.toMatch(/delete\s+x\b/);
+      expect(code).not.toMatch(/delete\s+ns\.x\b/);
+    },
+    run: { stdout: "true 1\ntrue 1\ntrue 1" },
+  });
+  itBundled("edgecase/DeleteFoldedNamespacePropertyRefMinify", {
+    files: {
+      "/entry.js": /* js */ `
+        import * as ns from "./m.js";
+        console.log(delete (null ?? ns.x), ns.x);
+      `,
+      "/m.js": /* js */ `
+        export let x = 1;
+      `,
+    },
+    minifySyntax: true,
+    minifyWhitespace: true,
+    run: { stdout: "true 1" },
+  });
+  // Same path via a direct named import: the identifier becomes an
+  // EImportIdentifier during the visit pass.
+  itBundled("edgecase/DeleteFoldedImportedBindingRef", {
+    files: {
+      "/entry.js": /* js */ `
+        import { x } from "./m.js";
+        console.log(delete (null ?? x), x);
+      `,
+      "/m.js": /* js */ `
+        export let x = 1;
+      `,
+    },
+    onAfterBundle: api => {
+      expect(api.readFile("out.js")).not.toMatch(/delete\s+x\b/);
+    },
+    run: { stdout: "true 1" },
+  });
 });
 
 for (const backend of ["api", "cli"] as const) {