bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Emit unused_attributes if a level attr only has a reason

Browse source
This commit is contained in:
xFrednet 2022-03-03 22:28:56 +01:00
parent 10913c0001
commit 700ec66aed
No known key found for this signature in database
GPG key ID: FCDCBF29AF64D601
6 changed files with 133 additions and 41 deletions
Download patch file Download diff file Expand all files Collapse all files

80
compiler/rustc_passes/src/check_attr.rs
View file

@ -4,7 +4,7 @@
//! conflicts between multiple such attributes attached to the same
//! item.
use rustc_ast::{ast, AttrStyle, Attribute, Lit, LitKind, NestedMetaItem};
use rustc_ast::{ast, AttrStyle, Attribute, Lit, LitKind, MetaItemKind, NestedMetaItem};
use rustc_data_structures::fx::FxHashMap;
use rustc_errors::{pluralize, struct_span_err, Applicability};
use rustc_feature::{AttributeDuplicates, AttributeType, BuiltinAttribute, BUILTIN_ATTRIBUTE_MAP};
@ -178,34 +178,7 @@ impl CheckAttrVisitor<'_> {
check_duplicates(self.tcx, attr, hir_id, *duplicates, &mut seen);
}
// Warn on useless empty attributes.
if matches!(
attr.name_or_empty(),
sym::macro_use
| sym::allow
| sym::warn
| sym::deny
| sym::forbid
| sym::feature
| sym::repr
| sym::target_feature
) && attr.meta_item_list().map_or(false, |list| list.is_empty())
{
self.tcx.struct_span_lint_hir(UNUSED_ATTRIBUTES, hir_id, attr.span, |lint| {
lint.build("unused attribute")
.span_suggestion(
attr.span,
"remove this attribute",
String::new(),
Applicability::MachineApplicable,
)
.note(&format!(
"attribute `{}` with an empty list has no effect",
attr.name_or_empty()
))
.emit();
});
}
self.check_unused_attribute(hir_id, attr)
}
if !is_valid {
@ -1969,6 +1942,55 @@ impl CheckAttrVisitor<'_> {
});
}
}
fn check_unused_attribute(&self, hir_id: HirId, attr: &Attribute) {
// Warn on useless empty attributes.
let note = if matches!(
attr.name_or_empty(),
sym::macro_use
| sym::allow
| sym::expect
| sym::warn
| sym::deny
| sym::forbid
| sym::feature
| sym::repr
| sym::target_feature
) && attr.meta_item_list().map_or(false, |list| list.is_empty())
{
format!(
"attribute `{}` with an empty list has no effect",
attr.name_or_empty()
)
} else if matches!(
attr.name_or_empty(),
sym::allow | sym::warn | sym::deny | sym::forbid | sym::expect
) && let Some(meta) = attr.meta_item_list()
&& meta.len() == 1
&& let Some(item) = meta[0].meta_item()
&& let MetaItemKind::NameValue(_) = &item.kind
&& item.path == sym::reason
{
format!(
"attribute `{}` without any lints has no effect",
attr.name_or_empty()
)
} else {
return;
};
self.tcx.struct_span_lint_hir(UNUSED_ATTRIBUTES, hir_id, attr.span, |lint| {
lint.build("unused attribute")
.span_suggestion(
attr.span,
"remove this attribute",
String::new(),
Applicability::MachineApplicable,
)
.note(&note)
.emit();
});
}
}
impl<'tcx> Visitor<'tcx> for CheckAttrVisitor<'tcx> {