dtolnay/cxx

Implement glob import semantics for builtin type names

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#682 创建于 2021年1月16日

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 (6 评论) (0 反应) (0 负责人)Rust (4,472 star) (253 fork)batch import
help wanted

描述

Currently we disallow any user-defined type name that collides with one of the builtin type names.

error[cxxbridge]: reserved name
  ┌─ src/main.rs:3:12
  │
3 │     struct UniquePtr { broken: bool }
  │            ^^^^^^^^^ reserved name

error[cxxbridge]: reserved name
  ┌─ src/main.rs:5:12
  │
5 │     struct c_char { broken: bool }
  │            ^^^^^^ reserved name

However, this is bad because it makes it a breaking change for us to add new builtin bindings, such as #681. If the user already had their own type with the same name as the new binding, that code needs to continue to work.

We need to implement basically the same semantics that Rust has for prelude types and glob imports — a user-defined type replaces any builtin binding of the same name.

贡献者指南

技术栈
rust
领域
developer experiencetooling
议题类型
feature
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
4
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
3-5 days
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
stale
清晰度议题是否清楚说明期望改动、验收标准和下一步。
mostly clear
前置要求
Rust programmingUnderstanding of cxx crate APIFamiliarity with Rust's glob imports
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
30
研究方向
Examine the cxx crate's source code for the reserved name validation logic (likely around the code generation step). Study how Rust implements glob import semantics for prelude types, and design a similar mechanism where user defined types shadow builtin bindings. The issue mentions #681 as an example of a new builtin binding that could break existing code; review that PR for context. Look at the error message output and the parsing of type names to understand where to implement the fallback.
Implement glob import semantics for builtin type names · dtolnay/cxx#682 | Good First Issue