syntax: Do not accidentally treat multi-segment meta-items as single-segment

Author: petrochenkov

src/librustc/hir/check_attr.rs

@@ -166,7 +166,7 @@ impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
         // ```
         let hints: Vec<_> = item.attrs
             .iter()
-            .filter(|attr| attr.name() == "repr")
+            .filter(|attr| attr.check_name("repr"))
             .filter_map(|attr| attr.meta_item_list())
             .flatten()
             .collect();
@@ -177,15 +177,15 @@ impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
         let mut is_transparent = false;
 
         for hint in &hints {
-            let name = if let Some(name) = hint.name() {
+            let name = if let Some(name) = hint.ident_str() {
                 name
             } else {
                 // Invalid repr hint like repr(42). We don't check for unrecognized hints here
                 // (libsyntax does that), so just ignore it.
                 continue;
             };
 
-            let (article, allowed_targets) = match &*name.as_str() {
+            let (article, allowed_targets) = match name {
                 "C" | "align" => {
                     is_c |= name == "C";
                     if target != Target::Struct &&
@@ -313,7 +313,7 @@ impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
 
     fn check_used(&self, item: &hir::Item, target: Target) {
         for attr in &item.attrs {
-            if attr.name() == "used" && target != Target::Static {
+            if attr.check_name("used") && target != Target::Static {
                 self.tcx.sess
                     .span_err(attr.span, "attribute must be applied to a `static` variable");
             }

src/librustc/ich/impls_syntax.rs

@@ -197,7 +197,8 @@ impl<'a> HashStable<StableHashingContext<'a>> for [ast::Attribute] {
         let filtered: SmallVec<[&ast::Attribute; 8]> = self
             .iter()
             .filter(|attr| {
-                !attr.is_sugared_doc && !hcx.is_ignored_attr(attr.name())
+                !attr.is_sugared_doc &&
+                !attr.ident().map_or(false, |ident| hcx.is_ignored_attr(ident.name))
             })
             .collect();
 
@@ -224,7 +225,7 @@ impl<'a> HashStable<StableHashingContext<'a>> for ast::Attribute {
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
         // Make sure that these have been filtered out.
-        debug_assert!(!hcx.is_ignored_attr(self.name()));
+        debug_assert!(!self.ident().map_or(false, |ident| hcx.is_ignored_attr(ident.name)));
         debug_assert!(!self.is_sugared_doc);
 
         let ast::Attribute {

src/librustc/lint/levels.rs

@@ -194,7 +194,7 @@ impl<'a> LintLevelsBuilder<'a> {
             struct_span_err!(sess, span, E0452, "malformed lint attribute")
         };
         for attr in attrs {
-            let level = match Level::from_str(&attr.name().as_str()) {
+            let level = match attr.ident_str().and_then(|name| Level::from_str(name)) {
                 None => continue,
                 Some(lvl) => lvl,
             };
@@ -255,9 +255,9 @@ impl<'a> LintLevelsBuilder<'a> {
             }
 
             for li in metas {
-                let word = match li.word() {
-                    Some(word) => word,
-                    None => {
+                let meta_item = match li.meta_item() {
+                    Some(meta_item) if meta_item.is_word() => meta_item,
+                    _ => {
                         let mut err = bad_attr(li.span);
                         if let Some(item) = li.meta_item() {
                             if let ast::MetaItemKind::NameValue(_) = item.node {
@@ -270,23 +270,24 @@ impl<'a> LintLevelsBuilder<'a> {
                         continue;
                     }
                 };
-                let tool_name = if let Some(lint_tool) = word.is_scoped() {
-                    if !attr::is_known_lint_tool(lint_tool) {
+                let tool_name = if meta_item.ident.segments.len() > 1 {
+                    let tool_ident = meta_item.ident.segments[0].ident;
+                    if !attr::is_known_lint_tool(tool_ident) {
                         span_err!(
                             sess,
-                            lint_tool.span,
+                            tool_ident.span,
                             E0710,
                             "an unknown tool name found in scoped lint: `{}`",
-                            word.ident
+                            meta_item.ident
                         );
                         continue;
                     }
 
-                    Some(lint_tool.as_str())
+                    Some(tool_ident.as_str())
                 } else {
                     None
                 };
-                let name = word.name();
+                let name = meta_item.ident.segments.last().expect("empty lint name").ident.name;
                 match store.check_lint_name(&name.as_str(), tool_name) {
                     CheckLintNameResult::Ok(ids) => {
                         let src = LintSource::Node(name, li.span, reason);

src/librustc/middle/lib_features.rs

@@ -65,9 +65,9 @@ impl<'a, 'tcx> LibFeatureCollector<'a, 'tcx> {
                 for meta in metas {
                     if let Some(mi) = meta.meta_item() {
                         // Find the `feature = ".."` meta-item.
-                        match (&*mi.name().as_str(), mi.value_str()) {
-                            ("feature", val) => feature = val,
-                            ("since", val) => since = val,
+                        match (mi.ident_str(), mi.value_str()) {
+                            (Some("feature"), val) => feature = val,
+                            (Some("since"), val) => since = val,
                             _ => {}
                         }
                     }

src/librustc/middle/stability.rs

@@ -194,11 +194,12 @@ impl<'a, 'tcx: 'a> Annotator<'a, 'tcx> {
         } else {
             // Emit errors for non-staged-api crates.
             for attr in attrs {
-                let tag = attr.name();
-                if tag == "unstable" || tag == "stable" || tag == "rustc_deprecated" {
-                    attr::mark_used(attr);
-                    self.tcx.sess.span_err(attr.span(), "stability attributes may not be used \
-                                                         outside of the standard library");
+                if let Some(tag) = attr.ident_str() {
+                    if tag == "unstable" || tag == "stable" || tag == "rustc_deprecated" {
+                        attr::mark_used(attr);
+                        self.tcx.sess.span_err(attr.span, "stability attributes may not be used \
+                                                           outside of the standard library");
+                    }
                 }
             }
 

src/librustc/session/config.rs

@@ -1850,7 +1850,8 @@ pub fn parse_cfgspecs(cfgspecs: Vec<String>) -> FxHashSet<(String, Option<String
                             error!("argument value must be a string");
                         }
                         MetaItemKind::NameValue(..) | MetaItemKind::Word => {
-                            return (meta_item.name(), meta_item.value_str());
+                            let ident = meta_item.ident().expect("multi-segment cfg key");
+                            return (ident.name, meta_item.value_str());
                         }
                     }
                 }

src/librustc/traits/on_unimplemented.rs

@@ -177,10 +177,12 @@ impl<'a, 'gcx, 'tcx> OnUnimplementedDirective {
         for command in self.subcommands.iter().chain(Some(self)).rev() {
             if let Some(ref condition) = command.condition {
                 if !attr::eval_condition(condition, &tcx.sess.parse_sess, &mut |c| {
-                    options.contains(&(
-                        c.name().as_str().to_string(),
-                        c.value_str().map(|s| s.as_str().to_string())
-                    ))
+                    c.ident_str().map_or(false, |name| {
+                        options.contains(&(
+                            name.to_string(),
+                            c.value_str().map(|s| s.as_str().to_string())
+                        ))
+                    })
                 }) {
                     debug!("evaluate: skipping {:?} due to condition", command);
                     continue

src/librustc_incremental/assert_dep_graph.rs

@@ -99,9 +99,9 @@ impl<'a, 'tcx> IfThisChanged<'a, 'tcx> {
     fn argument(&self, attr: &ast::Attribute) -> Option<ast::Name> {
         let mut value = None;
         for list_item in attr.meta_item_list().unwrap_or_default() {
-            match list_item.word() {
-                Some(word) if value.is_none() =>
-                    value = Some(word.name()),
+            match list_item.ident() {
+                Some(ident) if list_item.is_word() && value.is_none() =>
+                    value = Some(ident.name),
                 _ =>
                     // FIXME better-encapsulate meta_item (don't directly access `node`)
                     span_bug!(list_item.span(), "unexpected meta-item {:?}", list_item.node),

src/librustc_incremental/persist/dirty_clean.rs

@@ -576,7 +576,7 @@ fn expect_associated_value(tcx: TyCtxt<'_, '_, '_>, item: &NestedMetaItem) -> as
     if let Some(value) = item.value_str() {
         value
     } else {
-        let msg = if let Some(name) = item.name() {
+        let msg = if let Some(name) = item.ident_str() {
             format!("associated value expected for `{}`", name)
         } else {
             "expected an associated value".to_string()

src/librustc_lint/builtin.rs

@@ -760,7 +760,7 @@ impl LintPass for DeprecatedAttr {
 impl EarlyLintPass for DeprecatedAttr {
     fn check_attribute(&mut self, cx: &EarlyContext<'_>, attr: &ast::Attribute) {
         for &&(n, _, _, ref g) in &self.depr_attrs {
-            if attr.name() == n {
+            if attr.ident_str() == Some(n) {
                 if let &AttributeGate::Gated(Stability::Deprecated(link, suggestion),
                                              ref name,
                                              ref reason,