rust/compiler/rustc_builtin_macros/src/util.rs
Nicholas Nethercote c9ae38c71e Avoid unnecessary MetaItem/Attribute conversions.
`check_builtin_attribute` calls `parse_meta` to convert an `Attribute`
to a `MetaItem`, which it then checks. However, many callers of
`check_builtin_attribute` start with a `MetaItem`, and then convert it
to an `Attribute` by calling `cx.attribute(meta_item)`. This `MetaItem`
to `Attribute` to `MetaItem` conversion is silly.

This commit adds a new function `check_builtin_meta_item`, which can be
called instead from these call sites. `check_builtin_attribute` also now
calls it. The commit also renames `check_meta` as `check_attr` to better
match its arguments.
2022-11-29 12:08:57 +11:00

49 lines
2.0 KiB
Rust

use rustc_ast::{AttrStyle, Attribute, MetaItem};
use rustc_expand::base::{Annotatable, ExtCtxt};
use rustc_feature::AttributeTemplate;
use rustc_lint_defs::builtin::DUPLICATE_MACRO_ATTRIBUTES;
use rustc_parse::validate_attr;
use rustc_span::Symbol;
pub fn check_builtin_macro_attribute(ecx: &ExtCtxt<'_>, meta_item: &MetaItem, name: Symbol) {
// All the built-in macro attributes are "words" at the moment.
let template = AttributeTemplate { word: true, ..Default::default() };
validate_attr::check_builtin_meta_item(
&ecx.sess.parse_sess,
&meta_item,
AttrStyle::Outer,
name,
template,
);
}
/// Emit a warning if the item is annotated with the given attribute. This is used to diagnose when
/// an attribute may have been mistakenly duplicated.
pub fn warn_on_duplicate_attribute(ecx: &ExtCtxt<'_>, item: &Annotatable, name: Symbol) {
let attrs: Option<&[Attribute]> = match item {
Annotatable::Item(item) => Some(&item.attrs),
Annotatable::TraitItem(item) => Some(&item.attrs),
Annotatable::ImplItem(item) => Some(&item.attrs),
Annotatable::ForeignItem(item) => Some(&item.attrs),
Annotatable::Expr(expr) => Some(&expr.attrs),
Annotatable::Arm(arm) => Some(&arm.attrs),
Annotatable::ExprField(field) => Some(&field.attrs),
Annotatable::PatField(field) => Some(&field.attrs),
Annotatable::GenericParam(param) => Some(&param.attrs),
Annotatable::Param(param) => Some(&param.attrs),
Annotatable::FieldDef(def) => Some(&def.attrs),
Annotatable::Variant(variant) => Some(&variant.attrs),
_ => None,
};
if let Some(attrs) = attrs {
if let Some(attr) = ecx.sess.find_by_name(attrs, name) {
ecx.parse_sess().buffer_lint(
DUPLICATE_MACRO_ATTRIBUTES,
attr.span,
ecx.current_expansion.lint_node_id,
"duplicated attribute",
);
}
}
}