swc/crates/swc_ecma_codegen/tests/test262/9681f5d844d7acd0.js

(a)=>b; // 1 args
(a, b)=>c; // n args
()=>b; // 0 args
(a)=>(b)=>c; // func returns func returns func
(a)=>((b)=>c); // So these parens are dropped
()=>(b, c)=>d; // func returns func returns func
(a)=>{
    return b;
};
(a)=>"e"; // Dropping the parens