compiler/rustc_builtin_macros/src/util.rs

   1 use rustc_ast::{AttrStyle, Attribute, MetaItem};
   2 use rustc_expand::base::{Annotatable, ExtCtxt};
   3 use rustc_feature::AttributeTemplate;
   4 use rustc_lint_defs::builtin::DUPLICATE_MACRO_ATTRIBUTES;
   5 use rustc_parse::validate_attr;
   6 use rustc_span::Symbol;
   7
   8 pub fn check_builtin_macro_attribute(ecx: &ExtCtxt<'_>, meta_item: &MetaItem, name: Symbol) {
   9     // All the built-in macro attributes are "words" at the moment.
  10     let template = AttributeTemplate { word: true, ..Default::default() };
  11     validate_attr::check_builtin_meta_item(
  12         &ecx.sess.parse_sess,
  13         &meta_item,
  14         AttrStyle::Outer,
  15         name,
  16         template,
  17     );
  18 }
  19
  20 /// Emit a warning if the item is annotated with the given attribute. This is used to diagnose when
  21 /// an attribute may have been mistakenly duplicated.
  22 pub fn warn_on_duplicate_attribute(ecx: &ExtCtxt<'_>, item: &Annotatable, name: Symbol) {
  23     let attrs: Option<&[Attribute]> = match item {
  24         Annotatable::Item(item) => Some(&item.attrs),
  25         Annotatable::TraitItem(item) => Some(&item.attrs),
  26         Annotatable::ImplItem(item) => Some(&item.attrs),
  27         Annotatable::ForeignItem(item) => Some(&item.attrs),
  28         Annotatable::Expr(expr) => Some(&expr.attrs),
  29         Annotatable::Arm(arm) => Some(&arm.attrs),
  30         Annotatable::ExprField(field) => Some(&field.attrs),
  31         Annotatable::PatField(field) => Some(&field.attrs),
  32         Annotatable::GenericParam(param) => Some(&param.attrs),
  33         Annotatable::Param(param) => Some(&param.attrs),
  34         Annotatable::FieldDef(def) => Some(&def.attrs),
  35         Annotatable::Variant(variant) => Some(&variant.attrs),
  36         _ => None,
  37     };
  38     if let Some(attrs) = attrs {
  39         if let Some(attr) = ecx.sess.find_by_name(attrs, name) {
  40             ecx.parse_sess().buffer_lint(
  41                 DUPLICATE_MACRO_ATTRIBUTES,
  42                 attr.span,
  43                 ecx.current_expansion.lint_node_id,
  44                 "duplicated attribute",
  45             );
  46         }
  47     }
  48 }