Mirror of facebook/react#35383
Original author: gowthamrdyy

Summary

Fixes a bug where React Compiler generates code that uses Symbol.for() without qualifying it with globalThis, causing runtime errors when a user-defined component is named Symbol.

The Problem:
When a user defines a component named Symbol, it shadows the global built-in Symbol. The compiler-generated code (e.g., for memo cache sentinels) tries to call Symbol.for() but instead accesses the user's component, resulting in "Symbol.for is not a function".

Playground repro: Link

The Fix:
Updated CodegenReactiveFunction.ts to use globalThis.Symbol.for() instead of bare Symbol.for() references. This ensures the built-in global is always used, regardless of local variable names.

How did you test this change?

1. Added a new test fixture (component-named-symbol-shadows-global.js) that defines a component named Symbol.
   • Verified that this test case previously failed (or would produce broken code) and now compiles to correct code using globalThis.Symbol.
2. Verified generated output: checked that the compiled output for cache sentinels and early return sentinels now explicitly uses globalThis.Symbol.
3. Manual verification: Confirmed the fix addresses the issue reported in the playground.