Auto merge of #58899 - petrochenkov:derval2, r=estebank

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

Fixes https://github.com/rust-lang/rust/issues/55168 and many other regressions from https://github.com/rust-lang/rust/pull/50030

Basically, attributes like `#[any::prefix::foo]` were commonly interpreted as `#[foo]` due to `name()` successfully returning the last segment (this applies to nested things as well `#[attr(any::prefix::foo)]`).

2 files changed, 143 insertions, 163 deletions

diff --git a/src/libsyntax/attr/builtin.rs b/src/libsyntax/attr/builtin.rs
index f7a000935ca..cdfb83c6e56 100644
--- a/src/libsyntax/attr/builtin.rs
+++ b/src/libsyntax/attr/builtin.rs
@@ -1,6 +1,6 @@
 //! Parsing and validation of builtin attributes
 
-use crate::ast::{self, Attribute, MetaItem, Name, NestedMetaItemKind};
+use crate::ast::{self, Attribute, MetaItem, NestedMetaItem};
 use crate::feature_gate::{Features, GatedCfg};
 use crate::parse::ParseSess;
 
@@ -10,8 +10,8 @@ use syntax_pos::{symbol::Symbol, Span};
 use super::{mark_used, MetaItemKind};
 
 enum AttrError {
-    MultipleItem(Name),
-    UnknownMetaItem(Name, &'static [&'static str]),
+    MultipleItem(String),
+    UnknownMetaItem(String, &'static [&'static str]),
     MissingSince,
     MissingFeature,
     MultipleStabilityLevels,
@@ -155,10 +155,7 @@ pub fn contains_feature_attr(attrs: &[Attribute], feature_name: &str) -> bool {
     attrs.iter().any(|item| {
         item.check_name("feature") &&
         item.meta_item_list().map(|list| {
-            list.iter().any(|mi| {
-                mi.word().map(|w| w.name() == feature_name)
-                         .unwrap_or(false)
-            })
+            list.iter().any(|mi| mi.is_word() && mi.check_name(feature_name))
         }).unwrap_or(false)
     })
 }
@@ -206,7 +203,7 @@ fn find_stability_generic<'a, I>(sess: &ParseSess,
             let meta = meta.as_ref().unwrap();
             let get = |meta: &MetaItem, item: &mut Option<Symbol>| {
                 if item.is_some() {
-                    handle_errors(sess, meta.span, AttrError::MultipleItem(meta.name()));
+                    handle_errors(sess, meta.span, AttrError::MultipleItem(meta.path.to_string()));
                     return false
                 }
                 if let Some(v) = meta.value_str() {
@@ -225,9 +222,9 @@ fn find_stability_generic<'a, I>(sess: &ParseSess,
                     )+
                     for meta in metas {
                         if let Some(mi) = meta.meta_item() {
-                            match &*mi.name().as_str() {
+                            match mi.ident_str() {
                                 $(
-                                    stringify!($name)
+                                    Some(stringify!($name))
                                         => if !get(mi, &mut $name) { continue 'outer },
                                 )+
                                 _ => {
@@ -235,7 +232,7 @@ fn find_stability_generic<'a, I>(sess: &ParseSess,
                                     handle_errors(
                                         sess,
                                         mi.span,
-                                        AttrError::UnknownMetaItem(mi.name(), expected),
+                                        AttrError::UnknownMetaItem(mi.path.to_string(), expected),
                                     );
                                     continue 'outer
                                 }
@@ -243,7 +240,7 @@ fn find_stability_generic<'a, I>(sess: &ParseSess,
                         } else {
                             handle_errors(
                                 sess,
-                                meta.span,
+                                meta.span(),
                                 AttrError::UnsupportedLiteral(
                                     "unsupported literal",
                                     false,
@@ -255,7 +252,7 @@ fn find_stability_generic<'a, I>(sess: &ParseSess,
                 }
             }
 
-            match &*meta.name().as_str() {
+            match meta.ident_str().expect("not a stability level") {
                 "rustc_deprecated" => {
                     if rustc_depr.is_some() {
                         span_err!(diagnostic, item_sp, E0540,
@@ -274,11 +271,11 @@ fn find_stability_generic<'a, I>(sess: &ParseSess,
                             })
                         }
                         (None, _) => {
-                            handle_errors(sess, attr.span(), AttrError::MissingSince);
+                            handle_errors(sess, attr.span, AttrError::MissingSince);
                             continue
                         }
                         _ => {
-                            span_err!(diagnostic, attr.span(), E0543, "missing 'reason'");
+                            span_err!(diagnostic, attr.span, E0543, "missing 'reason'");
                             continue
                         }
                     }
@@ -294,13 +291,13 @@ fn find_stability_generic<'a, I>(sess: &ParseSess,
                     if let Some(feature) = feature {
                         rustc_const_unstable = Some(feature);
                     } else {
-                        span_err!(diagnostic, attr.span(), E0629, "missing 'feature'");
+                        span_err!(diagnostic, attr.span, E0629, "missing 'feature'");
                         continue
                     }
                 }
                 "unstable" => {
                     if stab.is_some() {
-                        handle_errors(sess, attr.span(), AttrError::MultipleStabilityLevels);
+                        handle_errors(sess, attr.span, AttrError::MultipleStabilityLevels);
                         break
                     }
 
@@ -309,16 +306,16 @@ fn find_stability_generic<'a, I>(sess: &ParseSess,
                     let mut issue = None;
                     for meta in metas {
                         if let Some(mi) = meta.meta_item() {
-                            match &*mi.name().as_str() {
-                                "feature" => if !get(mi, &mut feature) { continue 'outer },
-                                "reason" => if !get(mi, &mut reason) { continue 'outer },
-                                "issue" => if !get(mi, &mut issue) { continue 'outer },
+                            match mi.ident_str() {
+                                Some("feature") => if !get(mi, &mut feature) { continue 'outer },
+                                Some("reason") => if !get(mi, &mut reason) { continue 'outer },
+                                Some("issue") => if !get(mi, &mut issue) { continue 'outer },
                                 _ => {
                                     handle_errors(
                                         sess,
-                                        meta.span,
+                                        meta.span(),
                                         AttrError::UnknownMetaItem(
-                                            mi.name(),
+                                            mi.path.to_string(),
                                             &["feature", "reason", "issue"]
                                         ),
                                     );
@@ -328,7 +325,7 @@ fn find_stability_generic<'a, I>(sess: &ParseSess,
                         } else {
                             handle_errors(
                                 sess,
-                                meta.span,
+                                meta.span(),
                                 AttrError::UnsupportedLiteral(
                                     "unsupported literal",
                                     false,
@@ -347,7 +344,7 @@ fn find_stability_generic<'a, I>(sess: &ParseSess,
                                         if let Ok(issue) = issue.as_str().parse() {
                                             issue
                                         } else {
-                                            span_err!(diagnostic, attr.span(), E0545,
+                                            span_err!(diagnostic, attr.span, E0545,
                                                       "incorrect 'issue'");
                                             continue
                                         }
@@ -360,42 +357,44 @@ fn find_stability_generic<'a, I>(sess: &ParseSess,
                             })
                         }
                         (None, _, _) => {
-                            handle_errors(sess, attr.span(), AttrError::MissingFeature);
+                            handle_errors(sess, attr.span, AttrError::MissingFeature);
                             continue
                         }
                         _ => {
-                            span_err!(diagnostic, attr.span(), E0547, "missing 'issue'");
+                            span_err!(diagnostic, attr.span, E0547, "missing 'issue'");
                             continue
                         }
                     }
                 }
                 "stable" => {
                     if stab.is_some() {
-                        handle_errors(sess, attr.span(), AttrError::MultipleStabilityLevels);
+                        handle_errors(sess, attr.span, AttrError::MultipleStabilityLevels);
                         break
                     }
 
                     let mut feature = None;
                     let mut since = None;
                     for meta in metas {
-                        match &meta.node {
-                            NestedMetaItemKind::MetaItem(mi) => {
-                                match &*mi.name().as_str() {
-                                    "feature" => if !get(mi, &mut feature) { continue 'outer },
-                                    "since" => if !get(mi, &mut since) { continue 'outer },
+                        match meta {
+                            NestedMetaItem::MetaItem(mi) => {
+                                match mi.ident_str() {
+                                    Some("feature") =>
+                                        if !get(mi, &mut feature) { continue 'outer },
+                                    Some("since") =>
+                                        if !get(mi, &mut since) { continue 'outer },
                                     _ => {
                                         handle_errors(
                                             sess,
-                                            meta.span,
+                                            meta.span(),
                                             AttrError::UnknownMetaItem(
-                                                mi.name(), &["since", "note"],
+                                                mi.path.to_string(), &["since", "note"],
                                             ),
                                         );
                                         continue 'outer
                                     }
                                 }
                             },
-                            NestedMetaItemKind::Literal(lit) => {
+                            NestedMetaItem::Literal(lit) => {
                                 handle_errors(
                                     sess,
                                     lit.span,
@@ -422,11 +421,11 @@ fn find_stability_generic<'a, I>(sess: &ParseSess,
                             })
                         }
                         (None, _) => {
-                            handle_errors(sess, attr.span(), AttrError::MissingFeature);
+                            handle_errors(sess, attr.span, AttrError::MissingFeature);
                             continue
                         }
                         _ => {
-                            handle_errors(sess, attr.span(), AttrError::MissingSince);
+                            handle_errors(sess, attr.span, AttrError::MissingSince);
                             continue
                         }
                     }
@@ -483,8 +482,8 @@ pub fn cfg_matches(cfg: &ast::MetaItem, sess: &ParseSess, features: Option<&Feat
             gated_cfg.check_and_emit(sess, feats);
         }
         let error = |span, msg| { sess.span_diagnostic.span_err(span, msg); true };
-        if cfg.ident.segments.len() != 1 {
-            return error(cfg.ident.span, "`cfg` predicate key must be an identifier");
+        if cfg.path.segments.len() != 1 {
+            return error(cfg.path.span, "`cfg` predicate key must be an identifier");
         }
         match &cfg.node {
             MetaItemKind::List(..) => {
@@ -502,7 +501,8 @@ pub fn cfg_matches(cfg: &ast::MetaItem, sess: &ParseSess, features: Option<&Feat
                 true
             }
             MetaItemKind::NameValue(..) | MetaItemKind::Word => {
-                sess.config.contains(&(cfg.name(), cfg.value_str()))
+                let ident = cfg.ident().expect("multi-segment cfg predicate");
+                sess.config.contains(&(ident.name, cfg.value_str()))
             }
         }
     })
@@ -520,7 +520,7 @@ pub fn eval_condition<F>(cfg: &ast::MetaItem, sess: &ParseSess, eval: &mut F)
                 if !mi.is_meta_item() {
                     handle_errors(
                         sess,
-                        mi.span,
+                        mi.span(),
                         AttrError::UnsupportedLiteral(
                             "unsupported literal",
                             false
@@ -532,14 +532,14 @@ pub fn eval_condition<F>(cfg: &ast::MetaItem, sess: &ParseSess, eval: &mut F)
 
             // The unwraps below may look dangerous, but we've already asserted
             // that they won't fail with the loop above.
-            match &*cfg.name().as_str() {
-                "any" => mis.iter().any(|mi| {
+            match cfg.ident_str() {
+                Some("any") => mis.iter().any(|mi| {
                     eval_condition(mi.meta_item().unwrap(), sess, eval)
                 }),
-                "all" => mis.iter().all(|mi| {
+                Some("all") => mis.iter().all(|mi| {
                     eval_condition(mi.meta_item().unwrap(), sess, eval)
                 }),
-                "not" => {
+                Some("not") => {
                     if mis.len() != 1 {
                         span_err!(sess.span_diagnostic, cfg.span, E0536, "expected 1 cfg-pattern");
                         return false;
@@ -547,8 +547,9 @@ pub fn eval_condition<F>(cfg: &ast::MetaItem, sess: &ParseSess, eval: &mut F)
 
                     !eval_condition(mis[0].meta_item().unwrap(), sess, eval)
                 },
-                p => {
-                    span_err!(sess.span_diagnostic, cfg.span, E0537, "invalid predicate `{}`", p);
+                _ => {
+                    span_err!(sess.span_diagnostic, cfg.span, E0537,
+                              "invalid predicate `{}`", cfg.path);
                     false
                 }
             }
@@ -602,7 +603,9 @@ fn find_deprecation_generic<'a, I>(sess: &ParseSess,
             MetaItemKind::List(list) => {
                 let get = |meta: &MetaItem, item: &mut Option<Symbol>| {
                     if item.is_some() {
-                        handle_errors(sess, meta.span, AttrError::MultipleItem(meta.name()));
+                        handle_errors(
+                            sess, meta.span, AttrError::MultipleItem(meta.path.to_string())
+                        );
                         return false
                     }
                     if let Some(v) = meta.value_str() {
@@ -630,22 +633,23 @@ fn find_deprecation_generic<'a, I>(sess: &ParseSess,
                 let mut since = None;
                 let mut note = None;
                 for meta in list {
-                    match &meta.node {
-                        NestedMetaItemKind::MetaItem(mi) => {
-                            match &*mi.name().as_str() {
-                                "since" => if !get(mi, &mut since) { continue 'outer },
-                                "note" => if !get(mi, &mut note) { continue 'outer },
+                    match meta {
+                        NestedMetaItem::MetaItem(mi) => {
+                            match mi.ident_str() {
+                                Some("since") => if !get(mi, &mut since) { continue 'outer },
+                                Some("note") => if !get(mi, &mut note) { continue 'outer },
                                 _ => {
                                     handle_errors(
                                         sess,
-                                        meta.span,
-                                        AttrError::UnknownMetaItem(mi.name(), &["since", "note"]),
+                                        meta.span(),
+                                        AttrError::UnknownMetaItem(mi.path.to_string(),
+                                                                   &["since", "note"]),
                                     );
                                     continue 'outer
                                 }
                             }
                         }
-                        NestedMetaItemKind::Literal(lit) => {
+                        NestedMetaItem::Literal(lit) => {
                             handle_errors(
                                 sess,
                                 lit.span,
@@ -714,7 +718,7 @@ pub fn find_repr_attrs(sess: &ParseSess, attr: &Attribute) -> Vec<ReprAttr> {
                 if !item.is_meta_item() {
                     handle_errors(
                         sess,
-                        item.span,
+                        item.span(),
                         AttrError::UnsupportedLiteral(
                             "meta item in `repr` must be an identifier",
                             false,
@@ -724,19 +728,13 @@ pub fn find_repr_attrs(sess: &ParseSess, attr: &Attribute) -> Vec<ReprAttr> {
                 }
 
                 let mut recognised = false;
-                if let Some(mi) = item.word() {
-                    let word = &*mi.name().as_str();
-                    let hint = match word {
-                        "C" => Some(ReprC),
-                        "packed" => Some(ReprPacked(1)),
-                        "simd" => Some(ReprSimd),
-                        "transparent" => Some(ReprTransparent),
-                        _ => match int_type_of_word(word) {
-                            Some(ity) => Some(ReprInt(ity)),
-                            None => {
-                                None
-                            }
-                        }
+                if item.is_word() {
+                    let hint = match item.ident_str() {
+                        Some("C") => Some(ReprC),
+                        Some("packed") => Some(ReprPacked(1)),
+                        Some("simd") => Some(ReprSimd),
+                        Some("transparent") => Some(ReprTransparent),
+                        name => name.and_then(|name| int_type_of_word(name)).map(ReprInt),
                     };
 
                     if let Some(h) = hint {
@@ -777,20 +775,20 @@ pub fn find_repr_attrs(sess: &ParseSess, attr: &Attribute) -> Vec<ReprAttr> {
                         };
                     }
                     if let Some(literal_error) = literal_error {
-                        span_err!(diagnostic, item.span, E0589,
+                        span_err!(diagnostic, item.span(), E0589,
                                   "invalid `repr(align)` attribute: {}", literal_error);
                     }
                 } else {
                     if let Some(meta_item) = item.meta_item() {
-                        if meta_item.name() == "align" {
+                        if meta_item.check_name("align") {
                             if let MetaItemKind::NameValue(ref value) = meta_item.node {
                                 recognised = true;
-                                let mut err = struct_span_err!(diagnostic, item.span, E0693,
+                                let mut err = struct_span_err!(diagnostic, item.span(), E0693,
                                     "incorrect `repr(align)` attribute format");
                                 match value.node {
                                     ast::LitKind::Int(int, ast::LitIntType::Unsuffixed) => {
                                         err.span_suggestion(
-                                            item.span,
+                                            item.span(),
                                             "use parentheses instead",
                                             format!("align({})", int),
                                             Applicability::MachineApplicable
@@ -798,7 +796,7 @@ pub fn find_repr_attrs(sess: &ParseSess, attr: &Attribute) -> Vec<ReprAttr> {
                                     }
                                     ast::LitKind::Str(s, _) => {
                                         err.span_suggestion(
-                                            item.span,
+                                            item.span(),
                                             "use parentheses instead",
                                             format!("align({})", s),
                                             Applicability::MachineApplicable
@@ -813,7 +811,7 @@ pub fn find_repr_attrs(sess: &ParseSess, attr: &Attribute) -> Vec<ReprAttr> {
                 }
                 if !recognised {
                     // Not a word we recognize
-                    span_err!(diagnostic, item.span, E0552,
+                    span_err!(diagnostic, item.span(), E0552,
                               "unrecognized representation hint");
                 }
             }
diff --git a/src/libsyntax/attr/mod.rs b/src/libsyntax/attr/mod.rs
index b5fc8507314..1a8faa43fff 100644
--- a/src/libsyntax/attr/mod.rs
+++ b/src/libsyntax/attr/mod.rs
@@ -13,7 +13,7 @@ pub use StabilityLevel::*;
 
 use crate::ast;
 use crate::ast::{AttrId, Attribute, AttrStyle, Name, Ident, Path, PathSegment};
-use crate::ast::{MetaItem, MetaItemKind, NestedMetaItem, NestedMetaItemKind};
+use crate::ast::{MetaItem, MetaItemKind, NestedMetaItem};
 use crate::ast::{Lit, LitKind, Expr, ExprKind, Item, Local, Stmt, StmtKind, GenericParam};
 use crate::mut_visit::visit_clobber;
 use crate::source_map::{BytePos, Spanned, respan, dummy_spanned};
@@ -64,36 +64,33 @@ pub fn is_known_lint_tool(m_item: Ident) -> bool {
 }
 
 impl NestedMetaItem {
-    /// Returns the MetaItem if self is a NestedMetaItemKind::MetaItem.
+    /// Returns the MetaItem if self is a NestedMetaItem::MetaItem.
     pub fn meta_item(&self) -> Option<&MetaItem> {
-        match self.node {
-            NestedMetaItemKind::MetaItem(ref item) => Some(item),
+        match *self {
+            NestedMetaItem::MetaItem(ref item) => Some(item),
             _ => None
         }
     }
 
-    /// Returns the Lit if self is a NestedMetaItemKind::Literal.
+    /// Returns the Lit if self is a NestedMetaItem::Literal.
     pub fn literal(&self) -> Option<&Lit> {
-        match self.node {
-            NestedMetaItemKind::Literal(ref lit) => Some(lit),
+        match *self {
+            NestedMetaItem::Literal(ref lit) => Some(lit),
             _ => None
         }
     }
 
-    /// Returns the Span for `self`.
-    pub fn span(&self) -> Span {
-        self.span
-    }
-
     /// Returns `true` if this list item is a MetaItem with a name of `name`.
     pub fn check_name(&self, name: &str) -> bool {
         self.meta_item().map_or(false, |meta_item| meta_item.check_name(name))
     }
 
-    /// Returns the name of the meta item, e.g., `foo` in `#[foo]`,
-    /// `#[foo="bar"]` and `#[foo(bar)]`, if self is a MetaItem
-    pub fn name(&self) -> Option<Name> {
-        self.meta_item().and_then(|meta_item| Some(meta_item.name()))
+    /// For a single-segment meta-item returns its name, otherwise returns `None`.
+    pub fn ident(&self) -> Option<Ident> {
+        self.meta_item().and_then(|meta_item| meta_item.ident())
+    }
+    pub fn ident_str(&self) -> Option<&str> {
+        self.ident().map(|name| name.as_str().get())
     }
 
     /// Gets the string value if self is a MetaItem and the MetaItem is a
@@ -108,25 +105,14 @@ impl NestedMetaItem {
             |meta_item| meta_item.meta_item_list().and_then(
                 |meta_item_list| {
                     if meta_item_list.len() == 1 {
-                        let nested_item = &meta_item_list[0];
-                        if nested_item.is_literal() {
-                            Some((meta_item.name(), nested_item.literal().unwrap()))
-                        } else {
-                            None
+                        if let Some(ident) = meta_item.ident() {
+                            if let Some(lit) = meta_item_list[0].literal() {
+                                return Some((ident.name, lit));
+                            }
                         }
                     }
-                    else {
-                        None
-                    }}))
-    }
-
-    /// Returns a MetaItem if self is a MetaItem with Kind Word.
-    pub fn word(&self) -> Option<&MetaItem> {
-        self.meta_item().and_then(|meta_item| if meta_item.is_word() {
-            Some(meta_item)
-        } else {
-            None
-        })
+                    None
+                }))
     }
 
     /// Gets a list of inner meta items from a list MetaItem type.
@@ -146,7 +132,7 @@ impl NestedMetaItem {
 
     /// Returns `true` if self is a MetaItem and the meta item is a word.
     pub fn is_word(&self) -> bool {
-        self.word().is_some()
+        self.meta_item().map_or(false, |meta_item| meta_item.is_word())
     }
 
     /// Returns `true` if self is a MetaItem and the meta item is a ValueString.
@@ -160,10 +146,6 @@ impl NestedMetaItem {
     }
 }
 
-fn name_from_path(path: &Path) -> Name {
-    path.segments.last().expect("empty path in attribute").ident.name
-}
-
 impl Attribute {
     /// Returns `true` if the attribute's path matches the argument. If it matches, then the
     /// attribute is marked as used.
@@ -177,10 +159,16 @@ impl Attribute {
         matches
     }
 
-    /// Returns the **last** segment of the name of this attribute.
-    /// e.g., `foo` for `#[foo]`, `skip` for `#[rustfmt::skip]`.
-    pub fn name(&self) -> Name {
-        name_from_path(&self.path)
+    /// For a single-segment attribute returns its name, otherwise returns `None`.
+    pub fn ident(&self) -> Option<Ident> {
+        if self.path.segments.len() == 1 {
+            Some(self.path.segments[0].ident)
+        } else {
+            None
+        }
+    }
+    pub fn ident_str(&self) -> Option<&str> {
+        self.ident().map(|name| name.as_str().get())
     }
 
     pub fn value_str(&self) -> Option<Symbol> {
@@ -195,11 +183,7 @@ impl Attribute {
     }
 
     pub fn is_word(&self) -> bool {
-        self.path.segments.len() == 1 && self.tokens.is_empty()
-    }
-
-    pub fn span(&self) -> Span {
-        self.span
+        self.tokens.is_empty()
     }
 
     pub fn is_meta_item_list(&self) -> bool {
@@ -213,8 +197,16 @@ impl Attribute {
 }
 
 impl MetaItem {
-    pub fn name(&self) -> Name {
-        name_from_path(&self.ident)
+    /// For a single-segment meta-item returns its name, otherwise returns `None`.
+    pub fn ident(&self) -> Option<Ident> {
+        if self.path.segments.len() == 1 {
+            Some(self.path.segments[0].ident)
+        } else {
+            None
+        }
+    }
+    pub fn ident_str(&self) -> Option<&str> {
+        self.ident().map(|name| name.as_str().get())
     }
 
     // #[attribute(name = "value")]
@@ -252,10 +244,8 @@ impl MetaItem {
         }
     }
 
-    pub fn span(&self) -> Span { self.span }
-
     pub fn check_name(&self, name: &str) -> bool {
-        self.name() == name
+        self.path == name
     }
 
     pub fn is_value_str(&self) -> bool {
@@ -265,14 +255,6 @@ impl MetaItem {
     pub fn is_meta_item_list(&self) -> bool {
         self.meta_item_list().is_some()
     }
-
-    pub fn is_scoped(&self) -> Option<Ident> {
-        if self.ident.segments.len() > 1 {
-            Some(self.ident.segments[0].ident)
-        } else {
-            None
-        }
-    }
 }
 
 impl Attribute {
@@ -280,7 +262,7 @@ impl Attribute {
     pub fn meta(&self) -> Option<MetaItem> {
         let mut tokens = self.tokens.trees().peekable();
         Some(MetaItem {
-            ident: self.path.clone(),
+            path: self.path.clone(),
             node: if let Some(node) = MetaItemKind::from_tokens(&mut tokens) {
                 if tokens.peek().is_some() {
                     return None;
@@ -326,7 +308,7 @@ impl Attribute {
 
     pub fn parse_meta<'a>(&self, sess: &'a ParseSess) -> PResult<'a, MetaItem> {
         Ok(MetaItem {
-            ident: self.path.clone(),
+            path: self.path.clone(),
             node: self.parse(sess, |parser| parser.parse_meta_item_kind())?,
             span: self.span,
         })
@@ -364,19 +346,19 @@ pub fn mk_name_value_item_str(ident: Ident, value: Spanned<Symbol>) -> MetaItem
 }
 
 pub fn mk_name_value_item(span: Span, ident: Ident, value: ast::Lit) -> MetaItem {
-    MetaItem { ident: Path::from_ident(ident), span, node: MetaItemKind::NameValue(value) }
+    MetaItem { path: Path::from_ident(ident), span, node: MetaItemKind::NameValue(value) }
 }
 
 pub fn mk_list_item(span: Span, ident: Ident, items: Vec<NestedMetaItem>) -> MetaItem {
-    MetaItem { ident: Path::from_ident(ident), span, node: MetaItemKind::List(items) }
+    MetaItem { path: Path::from_ident(ident), span, node: MetaItemKind::List(items) }
 }
 
 pub fn mk_word_item(ident: Ident) -> MetaItem {
-    MetaItem { ident: Path::from_ident(ident), span: ident.span, node: MetaItemKind::Word }
+    MetaItem { path: Path::from_ident(ident), span: ident.span, node: MetaItemKind::Word }
 }
 
 pub fn mk_nested_word_item(ident: Ident) -> NestedMetaItem {
-    respan(ident.span, NestedMetaItemKind::MetaItem(mk_word_item(ident)))
+    NestedMetaItem::MetaItem(mk_word_item(ident))
 }
 
 pub fn mk_attr_id() -> AttrId {
@@ -400,7 +382,7 @@ pub fn mk_spanned_attr_inner(sp: Span, id: AttrId, item: MetaItem) -> Attribute
     Attribute {
         id,
         style: ast::AttrStyle::Inner,
-        path: item.ident,
+        path: item.path,
         tokens: item.node.tokens(item.span),
         is_sugared_doc: false,
         span: sp,
@@ -417,7 +399,7 @@ pub fn mk_spanned_attr_outer(sp: Span, id: AttrId, item: MetaItem) -> Attribute
     Attribute {
         id,
         style: ast::AttrStyle::Outer,
-        path: item.ident,
+        path: item.path,
         tokens: item.node.tokens(item.span),
         is_sugared_doc: false,
         span: sp,
@@ -468,7 +450,7 @@ impl MetaItem {
     fn tokens(&self) -> TokenStream {
         let mut idents = vec![];
         let mut last_pos = BytePos(0 as u32);
-        for (i, segment) in self.ident.segments.iter().enumerate() {
+        for (i, segment) in self.path.segments.iter().enumerate() {
             let is_first = i == 0;
             if !is_first {
                 let mod_sep_span = Span::new(last_pos,
@@ -488,7 +470,7 @@ impl MetaItem {
         where I: Iterator<Item = TokenTree>,
     {
         // FIXME: Share code with `parse_path`.
-        let ident = match tokens.next() {
+        let path = match tokens.next() {
             Some(TokenTree::Token(span, token @ Token::Ident(..))) |
             Some(TokenTree::Token(span, token @ Token::ModSep)) => 'arm: {
                 let mut segments = if let Token::Ident(ident, _) = token {
@@ -529,11 +511,11 @@ impl MetaItem {
         let node = MetaItemKind::from_tokens(tokens)?;
         let hi = match node {
             MetaItemKind::NameValue(ref lit) => lit.span.hi(),
-            MetaItemKind::List(..) => list_closing_paren_pos.unwrap_or(ident.span.hi()),
-            _ => ident.span.hi(),
+            MetaItemKind::List(..) => list_closing_paren_pos.unwrap_or(path.span.hi()),
+            _ => path.span.hi(),
         };
-        let span = ident.span.with_hi(hi);
-        Some(MetaItem { ident, node, span })
+        let span = path.span.with_hi(hi);
+        Some(MetaItem { path, node, span })
     }
 }
 
@@ -552,7 +534,7 @@ impl MetaItemKind {
                     if i > 0 {
                         tokens.push(TokenTree::Token(span, Token::Comma).into());
                     }
-                    item.node.tokens().append_to_tree_and_joint_vec(&mut tokens);
+                    item.tokens().append_to_tree_and_joint_vec(&mut tokens);
                 }
                 TokenTree::Delimited(
                     DelimSpan::from_single(span),
@@ -586,8 +568,8 @@ impl MetaItemKind {
         let mut tokens = delimited.into_trees().peekable();
         let mut result = Vec::new();
         while let Some(..) = tokens.peek() {
-            let item = NestedMetaItemKind::from_tokens(&mut tokens)?;
-            result.push(respan(item.span(), item));
+            let item = NestedMetaItem::from_tokens(&mut tokens)?;
+            result.push(item);
             match tokens.next() {
                 None | Some(TokenTree::Token(_, Token::Comma)) => {}
                 _ => return None,
@@ -597,32 +579,32 @@ impl MetaItemKind {
     }
 }
 
-impl NestedMetaItemKind {
-    fn span(&self) -> Span {
+impl NestedMetaItem {
+    pub fn span(&self) -> Span {
         match *self {
-            NestedMetaItemKind::MetaItem(ref item) => item.span,
-            NestedMetaItemKind::Literal(ref lit) => lit.span,
+            NestedMetaItem::MetaItem(ref item) => item.span,
+            NestedMetaItem::Literal(ref lit) => lit.span,
         }
     }
 
     fn tokens(&self) -> TokenStream {
         match *self {
-            NestedMetaItemKind::MetaItem(ref item) => item.tokens(),
-            NestedMetaItemKind::Literal(ref lit) => lit.tokens(),
+            NestedMetaItem::MetaItem(ref item) => item.tokens(),
+            NestedMetaItem::Literal(ref lit) => lit.tokens(),
         }
     }
 
-    fn from_tokens<I>(tokens: &mut iter::Peekable<I>) -> Option<NestedMetaItemKind>
+    fn from_tokens<I>(tokens: &mut iter::Peekable<I>) -> Option<NestedMetaItem>
         where I: Iterator<Item = TokenTree>,
     {
         if let Some(TokenTree::Token(span, token)) = tokens.peek().cloned() {
             if let Some(node) = LitKind::from_token(token) {
                 tokens.next();
-                return Some(NestedMetaItemKind::Literal(respan(span, node)));
+                return Some(NestedMetaItem::Literal(respan(span, node)));
             }
         }
 
-        MetaItem::from_tokens(tokens).map(NestedMetaItemKind::MetaItem)
+        MetaItem::from_tokens(tokens).map(NestedMetaItem::MetaItem)
     }
 }