Bug Report

🔎 Search Terms

shift left
type arguments
<<

🕗 Version & Regression Information

• This is a crash
• This changed between versions ______ and _______
• This is the behavior in every version I tried, and I reviewed the FAQ for entries about ____ Generics _____
• I was unable to test this on prior versions because _______

⏯ Playground Link

Playground link with relevant code

💻 Code

// No parse error.
(class extends f()< <T>(x: T) => T> {});
<Component< <T>(x: T) => T> />;

// Parse error.
(class extends f()<<T>(x: T) => T> {});
<Component<<T>(x: T) => T> />;

🙁 Actual behavior

Parsing error.

🙂 Expected behavior

No parse error. They are equivalent.

Additional Info

Found this issue when working on a similar fix to Babel (babel/babel#14145). This issue is a follow-up to #23996. /cc Wenlu Wang (@Kingwl) since you have fixed that issue.