如何从给定访问者的访客那里获得皮棉等级? [英] How do I get the lint level from a Visitor given a Block?

问题描述

出于各种原因，我将访问者用于HIR树遍历，而不是 依靠皮棉环境行走在树上.但是，这意味着我的皮棉 忽略源中的#[allow/warn/deny(..)]批注.我怎么能得到这个 回来吗?

For various reasons I use a Visitor for the HIR tree traversal instead of relying on the lint context to walk the tree. However, this means my lint ignores #[allow/warn/deny(..)] annotations in the source. How can I get this back?

我知道ctxt.levels，但是这些似乎没有帮助.其他功能 (例如with_lint_attrs(..)是上下文专有的.

I know of ctxt.levels, but those don't appear to help. The other functions (like with_lint_attrs(..) are private to the context.

推荐答案

由于我们的Rust没有解决方案，因此我

Since there was no solution with the Rust we had, I created the necessary callbacks in Rustc: With tonight's nightly, our LateLintPass has another check_block_post(..) method. So we can pull the Visitor stuff into the lint, and add a new field of type Option<&Block> that is set in the check_block(..) method and unset in the check_block_post(..) if the field is equal the current block, thus ignoring all contained blocks.

代码如下:

use syntax::ast::NodeId;

struct RegexLint { // some fields omitted
    last: Option<NodeId>
}
// concentrating on the block functions here:
impl LateLintPass for RegexLint {
    fn check_block(&mut self, cx: &LateContext, block: &Block) {
        if !self.last.is_none() { return; }
        // set self.last to Some(block.id) to ignore inner blocks
    }

    fn check_block_post(&mut self, _: &LateContext, block: &Block) {
        if self.last.map_or(false, |id| block.id == id) {
             self.last = None; // resume visiting blocks
        }
    }
}

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