규칙 6.10

const v = new V(); v.bump() is how TypeScript is ordinarily written, since a const fixes the name and not the object; nothing else holds the object new built, so the local is that object, and a write through it changes what TypeScript changes. A const that copies a value another name holds is where the two would part: TypeScript’s write reaches the object both names hold, and a write here would reach the copy alone, so the front end asks which is meant, a let to write a copy or the write on the value itself. Before this rule every write through a const was refused, with let as the remedy. A struct is a value here, so const w = v and let w = v copy it, where TypeScript hands w the object v holds; a write through either name after the copy is not seen through the other, which Rule 7.2’s table records.

ECMAScript let and const declarations (a const binding cannot be assigned again, and what it holds is not frozen); Value Declarations and var Declarations; Rule 8.10; surface §26.