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Rollup merge of #94433 - Urgau:check-cfg-allowness, r=petrochenkov

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Improve allowness of the unexpected_cfgs lint

This pull-request improve the allowness (`#[allow(...)]`) of the `unexpected_cfgs` lint.

Before this PR only crate level `#![allow(unexpected_cfgs)]` worked, now with this PR it also work when put around `cfg!` or if it is in a upper level. Making it work ~for the attributes `cfg`, `cfg_attr`, ...~ for the same level is awkward as the current code is design to give "Some parent node that is close to this macro call" (cf. https://doc.rust-lang.org/nightly/nightly-rustc/rustc_expand/base/struct.ExpansionData.html) meaning that allow on the same line as an attribute won't work. I'm note even sure if this would be possible.

Found while working on https://github.com/rust-lang/rust/pull/94298.
r? ````````@petrochenkov````````
This commit is contained in:
Dylan DPC
2022-03-03 01:09:12 +01:00
committed by GitHub
parent 7537b2036a 765205b9b8
commit 493ed7a6af
14 changed files with 122 additions and 26 deletions
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23
compiler/rustc_expand/src/expand.rs
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@@ -551,11 +551,6 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
// attribute is expanded. Therefore, we don't need to configure the tokens
// Derive macros *can* see the results of cfg-expansion - they are handled
// specially in `fully_expand_fragment`
cfg: StripUnconfigured {
sess: &self.cx.sess,
features: self.cx.ecfg.features,
config_tokens: false,
},
cx: self.cx,
invocations: Vec::new(),
monotonic: self.monotonic,
@@ -1538,12 +1533,20 @@ impl InvocationCollectorNode for AstLikeWrapper<P<ast::Expr>, OptExprTag> {
struct InvocationCollector<'a, 'b> {
cx: &'a mut ExtCtxt<'b>,
cfg: StripUnconfigured<'a>,
invocations: Vec<(Invocation, Option<Lrc<SyntaxExtension>>)>,
monotonic: bool,
}
impl<'a, 'b> InvocationCollector<'a, 'b> {
fn cfg(&self) -> StripUnconfigured<'_> {
StripUnconfigured {
sess: &self.cx.sess,
features: self.cx.ecfg.features,
config_tokens: false,
lint_node_id: self.cx.current_expansion.lint_node_id,
}
}
fn collect(&mut self, fragment_kind: AstFragmentKind, kind: InvocationKind) -> AstFragment {
let expn_id = LocalExpnId::fresh_empty();
let vis = kind.placeholder_visibility();
@@ -1683,7 +1686,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
attr: ast::Attribute,
pos: usize,
) -> bool {
let res = self.cfg.cfg_true(&attr);
let res = self.cfg().cfg_true(&attr);
if res {
// FIXME: `cfg(TRUE)` attributes do not currently remove themselves during expansion,
// and some tools like rustdoc and clippy rely on that. Find a way to remove them
@@ -1696,7 +1699,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
fn expand_cfg_attr(&self, node: &mut impl AstLike, attr: ast::Attribute, pos: usize) {
node.visit_attrs(|attrs| {
attrs.splice(pos..pos, self.cfg.expand_cfg_attr(attr, false));
attrs.splice(pos..pos, self.cfg().expand_cfg_attr(attr, false));
});
}
@@ -1718,7 +1721,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
continue;
}
_ => {
Node::pre_flat_map_node_collect_attr(&self.cfg, &attr);
Node::pre_flat_map_node_collect_attr(&self.cfg(), &attr);
self.collect_attr((attr, pos, derives), node.to_annotatable(), Node::KIND)
.make_ast::<Node>()
}
@@ -1882,7 +1885,7 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
fn visit_expr(&mut self, node: &mut P<ast::Expr>) {
// FIXME: Feature gating is performed inconsistently between `Expr` and `OptExpr`.
if let Some(attr) = node.attrs.first() {
self.cfg.maybe_emit_expr_attr_err(attr);
self.cfg().maybe_emit_expr_attr_err(attr);
}
self.visit_node(node)
}