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Compute a better lint_node_id during expansion

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When we need to emit a lint at a macro invocation, we currently use the
`NodeId` of its parent definition (e.g. the enclosing function). This
means that any `#[allow]` / `#[deny]` attributes placed 'closer' to the
macro (e.g. on an enclosing block or statement) will have no effect.

This commit computes a better `lint_node_id` in `InvocationCollector`.
When we visit/flat_map an AST node, we assign it a `NodeId` (earlier
than we normally would), and store than `NodeId` in current
`ExpansionData`. When we collect a macro invocation, the current
`lint_node_id` gets cloned along with our `ExpansionData`, allowing it
to be used if we need to emit a lint later on.

This improves the handling of `#[allow]` / `#[deny]` for
`SEMICOLON_IN_EXPRESSIONS_FROM_MACROS` and some `asm!`-related lints.
The 'legacy derive helpers' lint retains its current behavior
(I've inlined the now-removed `lint_node_id` function), since
there isn't an `ExpansionData` readily available.
This commit is contained in:
Aaron Hill 2021-07-14 18:24:12 -05:00
parent eb0b95b55a
commit ddd544856e
No known key found for this signature in database
GPG key ID: B4087E510E98B164
10 changed files with 139 additions and 65 deletions
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6
compiler/rustc_expand/src/base.rs
View file

@ -869,9 +869,6 @@ pub trait ResolverExpand {
fn check_unused_macros(&mut self);
/// Some parent node that is close enough to the given macro call.
fn lint_node_id(&self, expn_id: LocalExpnId) -> NodeId;
// Resolver interfaces for specific built-in macros.
/// Does `#[derive(...)]` attribute with the given `ExpnId` have built-in `Copy` inside it?
fn has_derive_copy(&self, expn_id: LocalExpnId) -> bool;
@ -926,6 +923,8 @@ pub struct ExpansionData {
pub module: Rc<ModuleData>,
pub dir_ownership: DirOwnership,
pub prior_type_ascription: Option<(Span, bool)>,
/// Some parent node that is close to this macro call
pub lint_node_id: NodeId,
}
type OnExternModLoaded<'a> =
@ -971,6 +970,7 @@ impl<'a> ExtCtxt<'a> {
module: Default::default(),
dir_ownership: DirOwnership::Owned { relative: None },
prior_type_ascription: None,
lint_node_id: ast::CRATE_NODE_ID,
},
force_mode: false,
expansions: FxHashMap::default(),

100
compiler/rustc_expand/src/expand.rs
View file

@ -1098,6 +1098,41 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
}
}
/// Wraps a call to `noop_visit_*` / `noop_flat_map_*`
/// This method assigns a `NodeId`, and sets that `NodeId`
/// as our current 'lint node id'. If a macro call is found
/// inside this AST node, we will use this AST node's `NodeId`
/// to emit lints associated with that macro (allowing
/// `#[allow]` / `#[deny]` to be applied close to
/// the macro invocation).
///
/// Do *not* call this for a macro AST node
/// (e.g. `ExprKind::MacCall`) - we cannot emit lints
/// at these AST nodes, since they are removed and
/// replaced with the result of macro expansion.
///
/// All other `NodeId`s are assigned by `visit_id`.
/// * `self` is the 'self' parameter for the current method,
/// * `id` is a mutable reference to the `NodeId` field
/// of the current AST node.
/// * `closure` is a closure that executes the
/// `noop_visit_*` / `noop_flat_map_*` method
/// for the current AST node.
macro_rules! assign_id {
($self:ident, $id:expr, $closure:expr) => {{
let old_id = $self.cx.current_expansion.lint_node_id;
if $self.monotonic {
debug_assert_eq!(*$id, ast::DUMMY_NODE_ID);
let new_id = $self.cx.resolver.next_node_id();
*$id = new_id;
$self.cx.current_expansion.lint_node_id = new_id;
}
let ret = ($closure)();
$self.cx.current_expansion.lint_node_id = old_id;
ret
}};
}
impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
self.cfg.configure_expr(expr);
@ -1118,7 +1153,9 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
self.check_attributes(&expr.attrs);
self.collect_bang(mac, expr.span, AstFragmentKind::Expr).make_expr().into_inner()
} else {
ensure_sufficient_stack(|| noop_visit_expr(&mut expr, self));
assign_id!(self, &mut expr.id, || {
ensure_sufficient_stack(|| noop_visit_expr(&mut expr, self));
});
expr
}
});
@ -1133,7 +1170,7 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
.make_arms();
}
noop_flat_map_arm(arm, self)
assign_id!(self, &mut arm.id, || noop_flat_map_arm(arm, self))
}
fn flat_map_expr_field(&mut self, field: ast::ExprField) -> SmallVec<[ast::ExprField; 1]> {
@ -1145,7 +1182,7 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
.make_expr_fields();
}
noop_flat_map_expr_field(field, self)
assign_id!(self, &mut field.id, || noop_flat_map_expr_field(field, self))
}
fn flat_map_pat_field(&mut self, fp: ast::PatField) -> SmallVec<[ast::PatField; 1]> {
@ -1157,7 +1194,7 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
.make_pat_fields();
}
noop_flat_map_pat_field(fp, self)
assign_id!(self, &mut fp.id, || noop_flat_map_pat_field(fp, self))
}
fn flat_map_param(&mut self, p: ast::Param) -> SmallVec<[ast::Param; 1]> {
@ -1169,7 +1206,7 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
.make_params();
}
noop_flat_map_param(p, self)
assign_id!(self, &mut p.id, || noop_flat_map_param(p, self))
}
fn flat_map_field_def(&mut self, sf: ast::FieldDef) -> SmallVec<[ast::FieldDef; 1]> {
@ -1181,7 +1218,7 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
.make_field_defs();
}
noop_flat_map_field_def(sf, self)
assign_id!(self, &mut sf.id, || noop_flat_map_field_def(sf, self))
}
fn flat_map_variant(&mut self, variant: ast::Variant) -> SmallVec<[ast::Variant; 1]> {
@ -1193,7 +1230,7 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
.make_variants();
}
noop_flat_map_variant(variant, self)
assign_id!(self, &mut variant.id, || noop_flat_map_variant(variant, self))
}
fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
@ -1214,9 +1251,11 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
.make_opt_expr()
.map(|expr| expr.into_inner())
} else {
Some({
noop_visit_expr(&mut expr, self);
expr
assign_id!(self, &mut expr.id, || {
Some({
noop_visit_expr(&mut expr, self);
expr
})
})
}
})
@ -1225,7 +1264,9 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
match pat.kind {
PatKind::MacCall(_) => {}
_ => return noop_visit_pat(pat, self),
_ => {
return assign_id!(self, &mut pat.id, || noop_visit_pat(pat, self));
}
}
visit_clobber(pat, |mut pat| match mem::replace(&mut pat.kind, PatKind::Wild) {
@ -1278,7 +1319,7 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
&mut self.cx.current_expansion.dir_ownership,
DirOwnership::UnownedViaBlock,
);
noop_visit_block(block, self);
assign_id!(self, &mut block.id, || noop_visit_block(block, self));
self.cx.current_expansion.dir_ownership = orig_dir_ownership;
}
@ -1377,7 +1418,7 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
let orig_dir_ownership =
mem::replace(&mut self.cx.current_expansion.dir_ownership, dir_ownership);
let result = noop_flat_map_item(item, self);
let result = assign_id!(self, &mut item.id, || noop_flat_map_item(item, self));
// Restore the module info.
self.cx.current_expansion.dir_ownership = orig_dir_ownership;
@ -1387,7 +1428,12 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
}
_ => {
item.attrs = attrs;
noop_flat_map_item(item, self)
// The crate root is special - don't assign an ID to it.
if !(matches!(item.kind, ast::ItemKind::Mod(..)) && ident == Ident::invalid()) {
assign_id!(self, &mut item.id, || noop_flat_map_item(item, self))
} else {
noop_flat_map_item(item, self)
}
}
}
}
@ -1411,7 +1457,9 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
_ => unreachable!(),
})
}
_ => noop_flat_map_assoc_item(item, self),
_ => {
assign_id!(self, &mut item.id, || noop_flat_map_assoc_item(item, self))
}
}
}
@ -1434,14 +1482,16 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
_ => unreachable!(),
})
}
_ => noop_flat_map_assoc_item(item, self),
_ => {
assign_id!(self, &mut item.id, || noop_flat_map_assoc_item(item, self))
}
}
}
fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
match ty.kind {
ast::TyKind::MacCall(_) => {}
_ => return noop_visit_ty(ty, self),
_ => return assign_id!(self, &mut ty.id, || noop_visit_ty(ty, self)),
};
visit_clobber(ty, |mut ty| match mem::replace(&mut ty.kind, ast::TyKind::Err) {
@ -1478,7 +1528,12 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
_ => unreachable!(),
})
}
_ => noop_flat_map_foreign_item(foreign_item, self),
_ => {
assign_id!(self, &mut foreign_item.id, || noop_flat_map_foreign_item(
foreign_item,
self
))
}
}
}
@ -1498,13 +1553,14 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
.make_generic_params();
}
noop_flat_map_generic_param(param, self)
assign_id!(self, &mut param.id, || noop_flat_map_generic_param(param, self))
}
fn visit_id(&mut self, id: &mut ast::NodeId) {
if self.monotonic {
debug_assert_eq!(*id, ast::DUMMY_NODE_ID);
*id = self.cx.resolver.next_node_id()
// We may have already assigned a `NodeId`
// by calling `assign_id`
if self.monotonic && *id == ast::DUMMY_NODE_ID {
*id = self.cx.resolver.next_node_id();
}
}
}

3
compiler/rustc_expand/src/mbe/macro_rules.rs
View file

@ -289,7 +289,6 @@ fn generic_extension<'cx>(
let mut p = Parser::new(sess, tts, false, None);
p.last_type_ascription = cx.current_expansion.prior_type_ascription;
let lint_node_id = cx.resolver.lint_node_id(cx.current_expansion.id);
// Let the context choose how to interpret the result.
// Weird, but useful for X-macros.
@ -301,7 +300,7 @@ fn generic_extension<'cx>(
// macro leaves unparsed tokens.
site_span: sp,
macro_ident: name,
lint_node_id,
lint_node_id: cx.current_expansion.lint_node_id,
arm_span,
});
}