From 549a14b7f521020d3860176e735142aec2203935 Mon Sep 17 00:00:00 2001
From: robobun <117481402+robobun@users.noreply.github.com>
Date: Mon, 27 Jul 2026 18:58:52 +0000
Subject: [PATCH] js_printer: parenthesize missing-import void 0 on LHS of **

A namespace-import property with no matching export is rewritten to
EImportIdentifier with import_item_status = Missing, which the printer
replaces with undefined. Under --minify-syntax that emits 'void 0',
and on the left of ** it was printed at Level::Exponentiation, below
print_undefined's Level::Prefix wrap threshold, producing the
SyntaxError 'void 0 ** 2'.

Bump left_level to Call for EImportIdentifier when minify_syntax is on,
mirroring the existing EBoolean arm. The non-Missing cases print an
identifier or a member access, neither of which consults the incoming
level, so the bump is a no-op there.
---
 src/js_printer/lib.rs                   |  6 ++++++
 test/bundler/esbuild/importstar.test.ts | 28 ++++++++++++++++++++++++-
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/js_printer/lib.rs b/src/js_printer/lib.rs
index 028828a4722e..dd467cbdda08 100644
--- a/src/js_printer/lib.rs
+++ b/src/js_printer/lib.rs
@@ -1533,6 +1533,12 @@ pub mod __gated_printer {
                                 v.left_level = Level::Call;
                             }
                         }
+                        ExprData::EImportIdentifier(_) => {
+                            // When minifying, a missing import prints as "void 0"
+                            if self.options.minify_syntax {
+                                v.left_level = Level::Call;
+                            }
+                        }
                         _ => {}
                     }
                 }
diff --git a/test/bundler/esbuild/importstar.test.ts b/test/bundler/esbuild/importstar.test.ts
index 8743b1df9ac4..11d977593ae8 100644
--- a/test/bundler/esbuild/importstar.test.ts
+++ b/test/bundler/esbuild/importstar.test.ts
@@ -1,4 +1,4 @@
-import { describe } from "bun:test";
+import { describe, expect } from "bun:test";
 import { itBundled } from "../expectBundled";
 
 // Tests ported from:
@@ -862,6 +862,32 @@ describe("bundler", () => {
       "/entry.js": [`Import "foo" will always be undefined because there is no matching export in "foo.js"`],
     },
   });
+  itBundled("importstar/NamespaceImportMissingES6ExponentiationLHS", {
+    files: {
+      "/entry.js": /* js */ `
+        import * as ns from './foo'
+        // A missing import prints as "void 0" under minify_syntax, which is not
+        // a valid left operand of ** unless parenthesized.
+        console.log(ns.nope ** 2, 2 ** ns.nope, ns.x ** 2)
+      `,
+      "/foo.js": `export const x = 3`,
+    },
+    minifySyntax: true,
+    run: {
+      stdout: "NaN NaN 9",
+    },
+    bundleWarnings: {
+      "/entry.js": [`Import "nope" will always be undefined because there is no matching export in "foo.js"`],
+    },
+    onAfterBundle(api) {
+      const out = api.readFile("/out.js");
+      expect(out).toContain("(void 0) ** 2");
+      expect(out).toContain("2 ** void 0");
+      // The existing export and the right operand stay unwrapped.
+      expect(out).not.toContain("(2 ** void 0)");
+      expect(out).not.toMatch(/\(\w+\) \*\* 2/);
+    },
+  });
   itBundled("importstar/ExportOtherCommonJS", {
     files: {
       "/entry.js": `export {bar} from './foo'`,