Microsoft/TypeScript

`const enum` references in the body of nodes with grammar errors are not inlined

Open

#58,209 创建于 2024年4月15日

在 GitHub 查看
 (0 评论) (0 反应) (0 负责人)TypeScript (6,726 fork)batch import
BugDomain: JS EmitHelp Wanted

仓库指标

Star
 (48,455 star)
PR 合并指标
 (平均合并 6天 17小时) (30 天内合并 9 个 PR)

描述

Acknowledgement

  • I acknowledge that issues using this template may be closed without further explanation at the maintainer's discretion.

Comment

Which results in output that's more broken than the input.

For example,

const enum A {
    a = 1,
    b = 2
}

A.a;

return {
    f() {
        return A.a;
    }
}

A top-level return is a grammar error, but is valid in old-style cjs modules at runtime, so is actually a vaguely reasonable grammar error to //@ts-ignore. The issue, however, is that the const enum reference within the body of that return statement -A.a is left as-is rather than being inlined, so at runtime it refers to something which does not exist.

This doesn't seem to be in any way intentional - this is a side effect of getConstantValue in the checker only using a cached resolvedSymbol, rather than ensuring one is available by checking/resolving the access expression first (which is also an issue for emit done before a full checker walk).

贡献者指南