Cleanup `Resolver::disallowed_shadowing`.

src/librustc_resolve/lib.rs

@@ -77,7 +77,7 @@
 use std::rc::Rc;
 
 use resolve_imports::{ImportDirective, NameResolution};
-use macros::{InvocationData, LegacyBinding, LegacyScope};
+use macros::{InvocationData, LegacyBinding};
 
 // NB: This module needs to be declared first so diagnostics are
 // registered before they are used.
@@ -1067,7 +1067,7 @@ pub struct Resolver<'a> {
 
     privacy_errors: Vec<PrivacyError<'a>>,
     ambiguity_errors: Vec<AmbiguityError<'a>>,
-    disallowed_shadowing: Vec<(Name, Span, LegacyScope<'a>)>,
+    disallowed_shadowing: Vec<&'a LegacyBinding<'a>>,
 
     arenas: &'a ResolverArenas<'a>,
     dummy_binding: &'a NameBinding<'a>,
@@ -3364,11 +3364,11 @@ fn report_errors(&mut self) {
 
     fn report_shadowing_errors(&mut self) {
         let mut reported_errors = FnvHashSet();
-        for (name, span, scope) in replace(&mut self.disallowed_shadowing, Vec::new()) {
-            if self.resolve_macro_name(scope, name, false).is_some() &&
-               reported_errors.insert((name, span)) {
-                let msg = format!("`{}` is already in scope", name);
-                self.session.struct_span_err(span, &msg)
+        for binding in replace(&mut self.disallowed_shadowing, Vec::new()) {
+            if self.resolve_macro_name(binding.parent, binding.name, false).is_some() &&
+               reported_errors.insert((binding.name, binding.span)) {
+                let msg = format!("`{}` is already in scope", binding.name);
+                self.session.struct_span_err(binding.span, &msg)
                     .note("macro-expanded `macro_rules!`s may not shadow \
                            existing macros (see RFC 1560)")
                     .emit();

src/librustc_resolve/macros.rs

@@ -74,10 +74,10 @@ fn simplify_expansion(mut invoc: &'a InvocationData<'a>) -> Self {
 }
 
 pub struct LegacyBinding<'a> {
-    parent: LegacyScope<'a>,
-    name: ast::Name,
+    pub parent: LegacyScope<'a>,
+    pub name: ast::Name,
     ext: Rc<SyntaxExtension>,
-    span: Span,
+    pub span: Span,
 }
 
 pub type LegacyImports = FnvHashMap<ast::Name, (Rc<SyntaxExtension>, Span)>;
@@ -213,7 +213,7 @@ pub fn resolve_macro_name(&mut self,
                 LegacyScope::Binding(binding) => {
                     if binding.name == name {
                         if record_used && relative_depth > 0 {
-                            self.disallowed_shadowing.push((name, binding.span, binding.parent));
+                            self.disallowed_shadowing.push(binding);
                         }
                         return Some(binding.ext.clone());
                     }