factor built-in attribute parsing into submodule

2 files changed, 718 insertions, 678 deletions

diff --git a/src/libsyntax/attr/builtin.rs b/src/libsyntax/attr/builtin.rs
new file mode 100644
index 00000000000..7b626a0fc27
--- /dev/null
+++ b/src/libsyntax/attr/builtin.rs
@@ -0,0 +1,708 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Parsing and validation of builtin attributes
+
+use ast::{self, Attribute, MetaItem, Name, NestedMetaItemKind};
+use errors::{Applicability, Handler};
+use feature_gate::{Features, GatedCfg};
+use parse::ParseSess;
+use syntax_pos::{symbol::Symbol, Span};
+
+use super::{list_contains_name, mark_used, MetaItemKind};
+
+enum AttrError {
+    MultipleItem(Name),
+    UnknownMetaItem(Name),
+    MissingSince,
+    MissingFeature,
+    MultipleStabilityLevels,
+    UnsupportedLiteral
+}
+
+fn handle_errors(diag: &Handler, span: Span, error: AttrError) {
+    match error {
+        AttrError::MultipleItem(item) => span_err!(diag, span, E0538,
+                                                   "multiple '{}' items", item),
+        AttrError::UnknownMetaItem(item) => span_err!(diag, span, E0541,
+                                                      "unknown meta item '{}'", item),
+        AttrError::MissingSince => span_err!(diag, span, E0542, "missing 'since'"),
+        AttrError::MissingFeature => span_err!(diag, span, E0546, "missing 'feature'"),
+        AttrError::MultipleStabilityLevels => span_err!(diag, span, E0544,
+                                                        "multiple stability levels"),
+        AttrError::UnsupportedLiteral => span_err!(diag, span, E0565, "unsupported literal"),
+    }
+}
+
+#[derive(Copy, Clone, Hash, PartialEq, RustcEncodable, RustcDecodable)]
+pub enum InlineAttr {
+    None,
+    Hint,
+    Always,
+    Never,
+}
+
+#[derive(Copy, Clone, PartialEq)]
+pub enum UnwindAttr {
+    Allowed,
+    Aborts,
+}
+
+/// Determine what `#[unwind]` attribute is present in `attrs`, if any.
+pub fn find_unwind_attr(diagnostic: Option<&Handler>, attrs: &[Attribute]) -> Option<UnwindAttr> {
+    let syntax_error = |attr: &Attribute| {
+        mark_used(attr);
+        diagnostic.map(|d| {
+            span_err!(d, attr.span, E0633, "malformed `#[unwind]` attribute");
+        });
+        None
+    };
+
+    attrs.iter().fold(None, |ia, attr| {
+        if attr.path != "unwind" {
+            return ia;
+        }
+        let meta = match attr.meta() {
+            Some(meta) => meta.node,
+            None => return ia,
+        };
+        match meta {
+            MetaItemKind::Word => {
+                syntax_error(attr)
+            }
+            MetaItemKind::List(ref items) => {
+                mark_used(attr);
+                if items.len() != 1 {
+                    syntax_error(attr)
+                } else if list_contains_name(&items[..], "allowed") {
+                    Some(UnwindAttr::Allowed)
+                } else if list_contains_name(&items[..], "aborts") {
+                    Some(UnwindAttr::Aborts)
+                } else {
+                    syntax_error(attr)
+                }
+            }
+            _ => ia,
+        }
+    })
+}
+
+/// Represents the #[stable], #[unstable], #[rustc_{deprecated,const_unstable}] attributes.
+#[derive(RustcEncodable, RustcDecodable, Clone, Debug, PartialEq, Eq, Hash)]
+pub struct Stability {
+    pub level: StabilityLevel,
+    pub feature: Symbol,
+    pub rustc_depr: Option<RustcDeprecation>,
+    pub rustc_const_unstable: Option<RustcConstUnstable>,
+}
+
+/// The available stability levels.
+#[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Clone, Debug, Eq, Hash)]
+pub enum StabilityLevel {
+    // Reason for the current stability level and the relevant rust-lang issue
+    Unstable { reason: Option<Symbol>, issue: u32 },
+    Stable { since: Symbol },
+}
+
+impl StabilityLevel {
+    pub fn is_unstable(&self) -> bool {
+        if let StabilityLevel::Unstable {..} = *self {
+            true
+        } else {
+            false
+        }
+    }
+    pub fn is_stable(&self) -> bool {
+        if let StabilityLevel::Stable {..} = *self {
+            true
+        } else {
+            false
+        }
+    }
+}
+
+#[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Clone, Debug, Eq, Hash)]
+pub struct RustcDeprecation {
+    pub since: Symbol,
+    pub reason: Symbol,
+}
+
+#[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Clone, Debug, Eq, Hash)]
+pub struct RustcConstUnstable {
+    pub feature: Symbol,
+}
+
+/// Check if `attrs` contains an attribute like `#![feature(feature_name)]`.
+/// This will not perform any "sanity checks" on the form of the attributes.
+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)
+            })
+        }).unwrap_or(false)
+    })
+}
+
+/// Find the first stability attribute. `None` if none exists.
+pub fn find_stability(diagnostic: &Handler, attrs: &[Attribute],
+                      item_sp: Span) -> Option<Stability> {
+    find_stability_generic(diagnostic, attrs.iter(), item_sp)
+}
+
+fn find_stability_generic<'a, I>(diagnostic: &Handler,
+                                 attrs_iter: I,
+                                 item_sp: Span)
+                                 -> Option<Stability>
+    where I: Iterator<Item = &'a Attribute>
+{
+    use self::StabilityLevel::*;
+
+    let mut stab: Option<Stability> = None;
+    let mut rustc_depr: Option<RustcDeprecation> = None;
+    let mut rustc_const_unstable: Option<RustcConstUnstable> = None;
+
+    'outer: for attr in attrs_iter {
+        if ![
+            "rustc_deprecated",
+            "rustc_const_unstable",
+            "unstable",
+            "stable",
+        ].iter().any(|&s| attr.path == s) {
+            continue // not a stability level
+        }
+
+        mark_used(attr);
+
+        let meta = attr.meta();
+        if let Some(MetaItem { node: MetaItemKind::List(ref metas), .. }) = meta {
+            let meta = meta.as_ref().unwrap();
+            let get = |meta: &MetaItem, item: &mut Option<Symbol>| {
+                if item.is_some() {
+                    handle_errors(diagnostic, meta.span, AttrError::MultipleItem(meta.name()));
+                    return false
+                }
+                if let Some(v) = meta.value_str() {
+                    *item = Some(v);
+                    true
+                } else {
+                    span_err!(diagnostic, meta.span, E0539, "incorrect meta item");
+                    false
+                }
+            };
+
+            macro_rules! get_meta {
+                ($($name:ident),+) => {
+                    $(
+                        let mut $name = None;
+                    )+
+                    for meta in metas {
+                        if let Some(mi) = meta.meta_item() {
+                            match &*mi.name().as_str() {
+                                $(
+                                    stringify!($name)
+                                        => if !get(mi, &mut $name) { continue 'outer },
+                                )+
+                                _ => {
+                                    handle_errors(diagnostic, mi.span,
+                                                  AttrError::UnknownMetaItem(mi.name()));
+                                    continue 'outer
+                                }
+                            }
+                        } else {
+                            handle_errors(diagnostic, meta.span, AttrError::UnsupportedLiteral);
+                            continue 'outer
+                        }
+                    }
+                }
+            }
+
+            match &*meta.name().as_str() {
+                "rustc_deprecated" => {
+                    if rustc_depr.is_some() {
+                        span_err!(diagnostic, item_sp, E0540,
+                                  "multiple rustc_deprecated attributes");
+                        continue 'outer
+                    }
+
+                    get_meta!(since, reason);
+
+                    match (since, reason) {
+                        (Some(since), Some(reason)) => {
+                            rustc_depr = Some(RustcDeprecation {
+                                since,
+                                reason,
+                            })
+                        }
+                        (None, _) => {
+                            handle_errors(diagnostic, attr.span(), AttrError::MissingSince);
+                            continue
+                        }
+                        _ => {
+                            span_err!(diagnostic, attr.span(), E0543, "missing 'reason'");
+                            continue
+                        }
+                    }
+                }
+                "rustc_const_unstable" => {
+                    if rustc_const_unstable.is_some() {
+                        span_err!(diagnostic, item_sp, E0553,
+                                  "multiple rustc_const_unstable attributes");
+                        continue 'outer
+                    }
+
+                    get_meta!(feature);
+                    if let Some(feature) = feature {
+                        rustc_const_unstable = Some(RustcConstUnstable {
+                            feature
+                        });
+                    } else {
+                        span_err!(diagnostic, attr.span(), E0629, "missing 'feature'");
+                        continue
+                    }
+                }
+                "unstable" => {
+                    if stab.is_some() {
+                        handle_errors(diagnostic, attr.span(), AttrError::MultipleStabilityLevels);
+                        break
+                    }
+
+                    let mut feature = None;
+                    let mut reason = None;
+                    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 },
+                                _ => {
+                                    handle_errors(diagnostic, meta.span,
+                                                  AttrError::UnknownMetaItem(mi.name()));
+                                    continue 'outer
+                                }
+                            }
+                        } else {
+                            handle_errors(diagnostic, meta.span, AttrError::UnsupportedLiteral);
+                            continue 'outer
+                        }
+                    }
+
+                    match (feature, reason, issue) {
+                        (Some(feature), reason, Some(issue)) => {
+                            stab = Some(Stability {
+                                level: Unstable {
+                                    reason,
+                                    issue: {
+                                        if let Ok(issue) = issue.as_str().parse() {
+                                            issue
+                                        } else {
+                                            span_err!(diagnostic, attr.span(), E0545,
+                                                      "incorrect 'issue'");
+                                            continue
+                                        }
+                                    }
+                                },
+                                feature,
+                                rustc_depr: None,
+                                rustc_const_unstable: None,
+                            })
+                        }
+                        (None, _, _) => {
+                            handle_errors(diagnostic, attr.span(), AttrError::MissingFeature);
+                            continue
+                        }
+                        _ => {
+                            span_err!(diagnostic, attr.span(), E0547, "missing 'issue'");
+                            continue
+                        }
+                    }
+                }
+                "stable" => {
+                    if stab.is_some() {
+                        handle_errors(diagnostic, attr.span(), AttrError::MultipleStabilityLevels);
+                        break
+                    }
+
+                    let mut feature = None;
+                    let mut since = None;
+                    for meta in metas {
+                        if let NestedMetaItemKind::MetaItem(ref mi) = meta.node {
+                            match &*mi.name().as_str() {
+                                "feature" => if !get(mi, &mut feature) { continue 'outer },
+                                "since" => if !get(mi, &mut since) { continue 'outer },
+                                _ => {
+                                    handle_errors(diagnostic, meta.span,
+                                                  AttrError::UnknownMetaItem(mi.name()));
+                                    continue 'outer
+                                }
+                            }
+                        } else {
+                            handle_errors(diagnostic, meta.span, AttrError::UnsupportedLiteral);
+                            continue 'outer
+                        }
+                    }
+
+                    match (feature, since) {
+                        (Some(feature), Some(since)) => {
+                            stab = Some(Stability {
+                                level: Stable {
+                                    since,
+                                },
+                                feature,
+                                rustc_depr: None,
+                                rustc_const_unstable: None,
+                            })
+                        }
+                        (None, _) => {
+                            handle_errors(diagnostic, attr.span(), AttrError::MissingFeature);
+                            continue
+                        }
+                        _ => {
+                            handle_errors(diagnostic, attr.span(), AttrError::MissingSince);
+                            continue
+                        }
+                    }
+                }
+                _ => unreachable!()
+            }
+        } else {
+            span_err!(diagnostic, attr.span(), E0548, "incorrect stability attribute type");
+            continue
+        }
+    }
+
+    // Merge the deprecation info into the stability info
+    if let Some(rustc_depr) = rustc_depr {
+        if let Some(ref mut stab) = stab {
+            stab.rustc_depr = Some(rustc_depr);
+        } else {
+            span_err!(diagnostic, item_sp, E0549,
+                      "rustc_deprecated attribute must be paired with \
+                       either stable or unstable attribute");
+        }
+    }
+
+    // Merge the const-unstable info into the stability info
+    if let Some(rustc_const_unstable) = rustc_const_unstable {
+        if let Some(ref mut stab) = stab {
+            stab.rustc_const_unstable = Some(rustc_const_unstable);
+        } else {
+            span_err!(diagnostic, item_sp, E0630,
+                      "rustc_const_unstable attribute must be paired with \
+                       either stable or unstable attribute");
+        }
+    }
+
+    stab
+}
+
+pub fn find_crate_name(attrs: &[Attribute]) -> Option<Symbol> {
+    super::first_attr_value_str_by_name(attrs, "crate_name")
+}
+
+/// Tests if a cfg-pattern matches the cfg set
+pub fn cfg_matches(cfg: &ast::MetaItem, sess: &ParseSess, features: Option<&Features>) -> bool {
+    eval_condition(cfg, sess, &mut |cfg| {
+        if let (Some(feats), Some(gated_cfg)) = (features, GatedCfg::gate(cfg)) {
+            gated_cfg.check_and_emit(sess, feats);
+        }
+        sess.config.contains(&(cfg.name(), cfg.value_str()))
+    })
+}
+
+/// Evaluate a cfg-like condition (with `any` and `all`), using `eval` to
+/// evaluate individual items.
+pub fn eval_condition<F>(cfg: &ast::MetaItem, sess: &ParseSess, eval: &mut F)
+                         -> bool
+    where F: FnMut(&ast::MetaItem) -> bool
+{
+    match cfg.node {
+        ast::MetaItemKind::List(ref mis) => {
+            for mi in mis.iter() {
+                if !mi.is_meta_item() {
+                    handle_errors(&sess.span_diagnostic, mi.span, AttrError::UnsupportedLiteral);
+                    return false;
+                }
+            }
+
+            // 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| {
+                    eval_condition(mi.meta_item().unwrap(), sess, eval)
+                }),
+                "all" => mis.iter().all(|mi| {
+                    eval_condition(mi.meta_item().unwrap(), sess, eval)
+                }),
+                "not" => {
+                    if mis.len() != 1 {
+                        span_err!(sess.span_diagnostic, cfg.span, E0536, "expected 1 cfg-pattern");
+                        return false;
+                    }
+
+                    !eval_condition(mis[0].meta_item().unwrap(), sess, eval)
+                },
+                p => {
+                    span_err!(sess.span_diagnostic, cfg.span, E0537, "invalid predicate `{}`", p);
+                    false
+                }
+            }
+        },
+        ast::MetaItemKind::Word | ast::MetaItemKind::NameValue(..) => {
+            eval(cfg)
+        }
+    }
+}
+
+
+#[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Clone, Debug, Eq, Hash)]
+pub struct Deprecation {
+    pub since: Option<Symbol>,
+    pub note: Option<Symbol>,
+}
+
+/// Find the deprecation attribute. `None` if none exists.
+pub fn find_deprecation(diagnostic: &Handler, attrs: &[Attribute],
+                        item_sp: Span) -> Option<Deprecation> {
+    find_deprecation_generic(diagnostic, attrs.iter(), item_sp)
+}
+
+fn find_deprecation_generic<'a, I>(diagnostic: &Handler,
+                                   attrs_iter: I,
+                                   item_sp: Span)
+                                   -> Option<Deprecation>
+    where I: Iterator<Item = &'a Attribute>
+{
+    let mut depr: Option<Deprecation> = None;
+
+    'outer: for attr in attrs_iter {
+        if attr.path != "deprecated" {
+            continue
+        }
+
+        mark_used(attr);
+
+        if depr.is_some() {
+            span_err!(diagnostic, item_sp, E0550, "multiple deprecated attributes");
+            break
+        }
+
+        depr = if let Some(metas) = attr.meta_item_list() {
+            let get = |meta: &MetaItem, item: &mut Option<Symbol>| {
+                if item.is_some() {
+                    handle_errors(diagnostic, meta.span, AttrError::MultipleItem(meta.name()));
+                    return false
+                }
+                if let Some(v) = meta.value_str() {
+                    *item = Some(v);
+                    true
+                } else {
+                    span_err!(diagnostic, meta.span, E0551, "incorrect meta item");
+                    false
+                }
+            };
+
+            let mut since = None;
+            let mut note = None;
+            for meta in metas {
+                if let NestedMetaItemKind::MetaItem(ref mi) = meta.node {
+                    match &*mi.name().as_str() {
+                        "since" => if !get(mi, &mut since) { continue 'outer },
+                        "note" => if !get(mi, &mut note) { continue 'outer },
+                        _ => {
+                            handle_errors(diagnostic, meta.span,
+                                          AttrError::UnknownMetaItem(mi.name()));
+                            continue 'outer
+                        }
+                    }
+                } else {
+                    handle_errors(diagnostic, meta.span, AttrError::UnsupportedLiteral);
+                    continue 'outer
+                }
+            }
+
+            Some(Deprecation {since: since, note: note})
+        } else {
+            Some(Deprecation{since: None, note: None})
+        }
+    }
+
+    depr
+}
+
+#[derive(PartialEq, Debug, RustcEncodable, RustcDecodable, Copy, Clone)]
+pub enum ReprAttr {
+    ReprInt(IntType),
+    ReprC,
+    ReprPacked(u32),
+    ReprSimd,
+    ReprTransparent,
+    ReprAlign(u32),
+}
+
+#[derive(Eq, Hash, PartialEq, Debug, RustcEncodable, RustcDecodable, Copy, Clone)]
+pub enum IntType {
+    SignedInt(ast::IntTy),
+    UnsignedInt(ast::UintTy)
+}
+
+impl IntType {
+    #[inline]
+    pub fn is_signed(self) -> bool {
+        use self::IntType::*;
+
+        match self {
+            SignedInt(..) => true,
+            UnsignedInt(..) => false
+        }
+    }
+}
+
+/// Parse #[repr(...)] forms.
+///
+/// Valid repr contents: any of the primitive integral type names (see
+/// `int_type_of_word`, below) to specify enum discriminant type; `C`, to use
+/// the same discriminant size that the corresponding C enum would or C
+/// structure layout, `packed` to remove padding, and `transparent` to elegate representation
+/// concerns to the only non-ZST field.
+pub fn find_repr_attrs(diagnostic: &Handler, attr: &Attribute) -> Vec<ReprAttr> {
+    use self::ReprAttr::*;
+
+    let mut acc = Vec::new();
+    if attr.path == "repr" {
+        if let Some(items) = attr.meta_item_list() {
+            mark_used(attr);
+            for item in items {
+                if !item.is_meta_item() {
+                    handle_errors(diagnostic, item.span, AttrError::UnsupportedLiteral);
+                    continue
+                }
+
+                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 let Some(h) = hint {
+                        recognised = true;
+                        acc.push(h);
+                    }
+                } else if let Some((name, value)) = item.name_value_literal() {
+                    let parse_alignment = |node: &ast::LitKind| -> Result<u32, &'static str> {
+                        if let ast::LitKind::Int(literal, ast::LitIntType::Unsuffixed) = node {
+                            if literal.is_power_of_two() {
+                                // rustc::ty::layout::Align restricts align to <= 2^29
+                                if *literal <= 1 << 29 {
+                                    Ok(*literal as u32)
+                                } else {
+                                    Err("larger than 2^29")
+                                }
+                            } else {
+                                Err("not a power of two")
+                            }
+                        } else {
+                            Err("not an unsuffixed integer")
+                        }
+                    };
+
+                    let mut literal_error = None;
+                    if name == "align" {
+                        recognised = true;
+                        match parse_alignment(&value.node) {
+                            Ok(literal) => acc.push(ReprAlign(literal)),
+                            Err(message) => literal_error = Some(message)
+                        };
+                    }
+                    else if name == "packed" {
+                        recognised = true;
+                        match parse_alignment(&value.node) {
+                            Ok(literal) => acc.push(ReprPacked(literal)),
+                            Err(message) => literal_error = Some(message)
+                        };
+                    }
+                    if let Some(literal_error) = literal_error {
+                        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 let MetaItemKind::NameValue(ref value) = meta_item.node {
+                                recognised = true;
+                                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_with_applicability(
+                                            item.span,
+                                            "use parentheses instead",
+                                            format!("align({})", int),
+                                            Applicability::MachineApplicable
+                                        );
+                                    }
+                                    ast::LitKind::Str(s, _) => {
+                                        err.span_suggestion_with_applicability(
+                                            item.span,
+                                            "use parentheses instead",
+                                            format!("align({})", s),
+                                            Applicability::MachineApplicable
+                                        );
+                                    }
+                                    _ => {}
+                                }
+                                err.emit();
+                            }
+                        }
+                    }
+                }
+                if !recognised {
+                    // Not a word we recognize
+                    span_err!(diagnostic, item.span, E0552,
+                              "unrecognized representation hint");
+                }
+            }
+        }
+    }
+    acc
+}
+
+fn int_type_of_word(s: &str) -> Option<IntType> {
+    use self::IntType::*;
+
+    match s {
+        "i8" => Some(SignedInt(ast::IntTy::I8)),
+        "u8" => Some(UnsignedInt(ast::UintTy::U8)),
+        "i16" => Some(SignedInt(ast::IntTy::I16)),
+        "u16" => Some(UnsignedInt(ast::UintTy::U16)),
+        "i32" => Some(SignedInt(ast::IntTy::I32)),
+        "u32" => Some(UnsignedInt(ast::UintTy::U32)),
+        "i64" => Some(SignedInt(ast::IntTy::I64)),
+        "u64" => Some(UnsignedInt(ast::UintTy::U64)),
+        "i128" => Some(SignedInt(ast::IntTy::I128)),
+        "u128" => Some(UnsignedInt(ast::UintTy::U128)),
+        "isize" => Some(SignedInt(ast::IntTy::Isize)),
+        "usize" => Some(UnsignedInt(ast::UintTy::Usize)),
+        _ => None
+    }
+}
diff --git a/src/libsyntax/attr.rs b/src/libsyntax/attr/mod.rs
index ded493fe395..4e27d6c1525 100644
--- a/src/libsyntax/attr.rs
+++ b/src/libsyntax/attr/mod.rs
@@ -8,11 +8,18 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// Functions dealing with attributes and meta items
+//! Functions dealing with attributes and meta items
 
-pub use self::StabilityLevel::*;
-pub use self::ReprAttr::*;
+mod builtin;
+
+pub use self::builtin::{
+    cfg_matches, contains_feature_attr, eval_condition, find_crate_name, find_deprecation,
+    find_repr_attrs, find_stability, find_unwind_attr, Deprecation, InlineAttr, IntType, ReprAttr,
+    RustcConstUnstable, RustcDeprecation, Stability, StabilityLevel, UnwindAttr,
+};
 pub use self::IntType::*;
+pub use self::ReprAttr::*;
+pub use self::StabilityLevel::*;
 
 use ast;
 use ast::{AttrId, Attribute, Name, Ident, Path, PathSegment};
@@ -20,8 +27,6 @@ use ast::{MetaItem, MetaItemKind, NestedMetaItem, NestedMetaItemKind};
 use ast::{Lit, LitKind, Expr, ExprKind, Item, Local, Stmt, StmtKind, GenericParam};
 use codemap::{BytePos, Spanned, respan, dummy_spanned};
 use syntax_pos::Span;
-use errors::{Applicability, Handler};
-use feature_gate::{Features, GatedCfg};
 use parse::lexer::comments::{doc_comment_style, strip_doc_comment_decoration};
 use parse::parser::Parser;
 use parse::{self, ParseSess, PResult};
@@ -34,29 +39,6 @@ use GLOBALS;
 
 use std::iter;
 
-enum AttrError {
-    MultipleItem(Name),
-    UnknownMetaItem(Name),
-    MissingSince,
-    MissingFeature,
-    MultipleStabilityLevels,
-    UnsupportedLiteral
-}
-
-fn handle_errors(diag: &Handler, span: Span, error: AttrError) {
-    match error {
-        AttrError::MultipleItem(item) => span_err!(diag, span, E0538,
-                                                   "multiple '{}' items", item),
-        AttrError::UnknownMetaItem(item) => span_err!(diag, span, E0541,
-                                                      "unknown meta item '{}'", item),
-        AttrError::MissingSince => span_err!(diag, span, E0542, "missing 'since'"),
-        AttrError::MissingFeature => span_err!(diag, span, E0546, "missing 'feature'"),
-        AttrError::MultipleStabilityLevels => span_err!(diag, span, E0544,
-                                                        "multiple stability levels"),
-        AttrError::UnsupportedLiteral => span_err!(diag, span, E0565, "unsupported literal"),
-    }
-}
-
 pub fn mark_used(attr: &Attribute) {
     debug!("Marking {:?} as used.", attr);
     let AttrId(id) = attr.id;
@@ -442,7 +424,6 @@ pub fn mk_spanned_attr_inner(sp: Span, id: AttrId, item: MetaItem) -> Attribute
     }
 }
 
-
 /// Returns an outer attribute with the given value.
 pub fn mk_attr_outer(span: Span, id: AttrId, item: MetaItem) -> Attribute {
     mk_spanned_attr_outer(span, id, item)
@@ -495,655 +476,6 @@ pub fn first_attr_value_str_by_name(attrs: &[Attribute], name: &str) -> Option<S
         .and_then(|at| at.value_str())
 }
 
-/// Check if `attrs` contains an attribute like `#![feature(feature_name)]`.
-/// This will not perform any "sanity checks" on the form of the attributes.
-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)
-            })
-        }).unwrap_or(false)
-    })
-}
-
-/* Higher-level applications */
-
-pub fn find_crate_name(attrs: &[Attribute]) -> Option<Symbol> {
-    first_attr_value_str_by_name(attrs, "crate_name")
-}
-
-#[derive(Copy, Clone, Hash, PartialEq, RustcEncodable, RustcDecodable)]
-pub enum InlineAttr {
-    None,
-    Hint,
-    Always,
-    Never,
-}
-
-#[derive(Copy, Clone, PartialEq)]
-pub enum UnwindAttr {
-    Allowed,
-    Aborts,
-}
-
-/// Determine what `#[unwind]` attribute is present in `attrs`, if any.
-pub fn find_unwind_attr(diagnostic: Option<&Handler>, attrs: &[Attribute]) -> Option<UnwindAttr> {
-    let syntax_error = |attr: &Attribute| {
-        mark_used(attr);
-        diagnostic.map(|d| {
-            span_err!(d, attr.span, E0633, "malformed `#[unwind]` attribute");
-        });
-        None
-    };
-
-    attrs.iter().fold(None, |ia, attr| {
-        if attr.path != "unwind" {
-            return ia;
-        }
-        let meta = match attr.meta() {
-            Some(meta) => meta.node,
-            None => return ia,
-        };
-        match meta {
-            MetaItemKind::Word => {
-                syntax_error(attr)
-            }
-            MetaItemKind::List(ref items) => {
-                mark_used(attr);
-                if items.len() != 1 {
-                    syntax_error(attr)
-                } else if list_contains_name(&items[..], "allowed") {
-                    Some(UnwindAttr::Allowed)
-                } else if list_contains_name(&items[..], "aborts") {
-                    Some(UnwindAttr::Aborts)
-                } else {
-                    syntax_error(attr)
-                }
-            }
-            _ => ia,
-        }
-    })
-}
-
-
-/// Tests if a cfg-pattern matches the cfg set
-pub fn cfg_matches(cfg: &ast::MetaItem, sess: &ParseSess, features: Option<&Features>) -> bool {
-    eval_condition(cfg, sess, &mut |cfg| {
-        if let (Some(feats), Some(gated_cfg)) = (features, GatedCfg::gate(cfg)) {
-            gated_cfg.check_and_emit(sess, feats);
-        }
-        sess.config.contains(&(cfg.name(), cfg.value_str()))
-    })
-}
-
-/// Evaluate a cfg-like condition (with `any` and `all`), using `eval` to
-/// evaluate individual items.
-pub fn eval_condition<F>(cfg: &ast::MetaItem, sess: &ParseSess, eval: &mut F)
-                         -> bool
-    where F: FnMut(&ast::MetaItem) -> bool
-{
-    match cfg.node {
-        ast::MetaItemKind::List(ref mis) => {
-            for mi in mis.iter() {
-                if !mi.is_meta_item() {
-                    handle_errors(&sess.span_diagnostic, mi.span, AttrError::UnsupportedLiteral);
-                    return false;
-                }
-            }
-
-            // 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| {
-                    eval_condition(mi.meta_item().unwrap(), sess, eval)
-                }),
-                "all" => mis.iter().all(|mi| {
-                    eval_condition(mi.meta_item().unwrap(), sess, eval)
-                }),
-                "not" => {
-                    if mis.len() != 1 {
-                        span_err!(sess.span_diagnostic, cfg.span, E0536, "expected 1 cfg-pattern");
-                        return false;
-                    }
-
-                    !eval_condition(mis[0].meta_item().unwrap(), sess, eval)
-                },
-                p => {
-                    span_err!(sess.span_diagnostic, cfg.span, E0537, "invalid predicate `{}`", p);
-                    false
-                }
-            }
-        },
-        ast::MetaItemKind::Word | ast::MetaItemKind::NameValue(..) => {
-            eval(cfg)
-        }
-    }
-}
-
-/// Represents the #[stable], #[unstable], #[rustc_{deprecated,const_unstable}] attributes.
-#[derive(RustcEncodable, RustcDecodable, Clone, Debug, PartialEq, Eq, Hash)]
-pub struct Stability {
-    pub level: StabilityLevel,
-    pub feature: Symbol,
-    pub rustc_depr: Option<RustcDeprecation>,
-    pub rustc_const_unstable: Option<RustcConstUnstable>,
-}
-
-/// The available stability levels.
-#[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Clone, Debug, Eq, Hash)]
-pub enum StabilityLevel {
-    // Reason for the current stability level and the relevant rust-lang issue
-    Unstable { reason: Option<Symbol>, issue: u32 },
-    Stable { since: Symbol },
-}
-
-#[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Clone, Debug, Eq, Hash)]
-pub struct RustcDeprecation {
-    pub since: Symbol,
-    pub reason: Symbol,
-}
-
-#[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Clone, Debug, Eq, Hash)]
-pub struct RustcConstUnstable {
-    pub feature: Symbol,
-}
-
-#[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Clone, Debug, Eq, Hash)]
-pub struct Deprecation {
-    pub since: Option<Symbol>,
-    pub note: Option<Symbol>,
-}
-
-impl StabilityLevel {
-    pub fn is_unstable(&self) -> bool { if let Unstable {..} = *self { true } else { false }}
-    pub fn is_stable(&self) -> bool { if let Stable {..} = *self { true } else { false }}
-}
-
-fn find_stability_generic<'a, I>(diagnostic: &Handler,
-                                 attrs_iter: I,
-                                 item_sp: Span)
-                                 -> Option<Stability>
-    where I: Iterator<Item = &'a Attribute>
-{
-    let mut stab: Option<Stability> = None;
-    let mut rustc_depr: Option<RustcDeprecation> = None;
-    let mut rustc_const_unstable: Option<RustcConstUnstable> = None;
-
-    'outer: for attr in attrs_iter {
-        if ![
-            "rustc_deprecated",
-            "rustc_const_unstable",
-            "unstable",
-            "stable",
-        ].iter().any(|&s| attr.path == s) {
-            continue // not a stability level
-        }
-
-        mark_used(attr);
-
-        let meta = attr.meta();
-        if let Some(MetaItem { node: MetaItemKind::List(ref metas), .. }) = meta {
-            let meta = meta.as_ref().unwrap();
-            let get = |meta: &MetaItem, item: &mut Option<Symbol>| {
-                if item.is_some() {
-                    handle_errors(diagnostic, meta.span, AttrError::MultipleItem(meta.name()));
-                    return false
-                }
-                if let Some(v) = meta.value_str() {
-                    *item = Some(v);
-                    true
-                } else {
-                    span_err!(diagnostic, meta.span, E0539, "incorrect meta item");
-                    false
-                }
-            };
-
-            macro_rules! get_meta {
-                ($($name:ident),+) => {
-                    $(
-                        let mut $name = None;
-                    )+
-                    for meta in metas {
-                        if let Some(mi) = meta.meta_item() {
-                            match &*mi.name().as_str() {
-                                $(
-                                    stringify!($name)
-                                        => if !get(mi, &mut $name) { continue 'outer },
-                                )+
-                                _ => {
-                                    handle_errors(diagnostic, mi.span,
-                                                  AttrError::UnknownMetaItem(mi.name()));
-                                    continue 'outer
-                                }
-                            }
-                        } else {
-                            handle_errors(diagnostic, meta.span, AttrError::UnsupportedLiteral);
-                            continue 'outer
-                        }
-                    }
-                }
-            }
-
-            match &*meta.name().as_str() {
-                "rustc_deprecated" => {
-                    if rustc_depr.is_some() {
-                        span_err!(diagnostic, item_sp, E0540,
-                                  "multiple rustc_deprecated attributes");
-                        continue 'outer
-                    }
-
-                    get_meta!(since, reason);
-
-                    match (since, reason) {
-                        (Some(since), Some(reason)) => {
-                            rustc_depr = Some(RustcDeprecation {
-                                since,
-                                reason,
-                            })
-                        }
-                        (None, _) => {
-                            handle_errors(diagnostic, attr.span(), AttrError::MissingSince);
-                            continue
-                        }
-                        _ => {
-                            span_err!(diagnostic, attr.span(), E0543, "missing 'reason'");
-                            continue
-                        }
-                    }
-                }
-                "rustc_const_unstable" => {
-                    if rustc_const_unstable.is_some() {
-                        span_err!(diagnostic, item_sp, E0553,
-                                  "multiple rustc_const_unstable attributes");
-                        continue 'outer
-                    }
-
-                    get_meta!(feature);
-                    if let Some(feature) = feature {
-                        rustc_const_unstable = Some(RustcConstUnstable {
-                            feature
-                        });
-                    } else {
-                        span_err!(diagnostic, attr.span(), E0629, "missing 'feature'");
-                        continue
-                    }
-                }
-                "unstable" => {
-                    if stab.is_some() {
-                        handle_errors(diagnostic, attr.span(), AttrError::MultipleStabilityLevels);
-                        break
-                    }
-
-                    let mut feature = None;
-                    let mut reason = None;
-                    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 },
-                                _ => {
-                                    handle_errors(diagnostic, meta.span,
-                                                  AttrError::UnknownMetaItem(mi.name()));
-                                    continue 'outer
-                                }
-                            }
-                        } else {
-                            handle_errors(diagnostic, meta.span, AttrError::UnsupportedLiteral);
-                            continue 'outer
-                        }
-                    }
-
-                    match (feature, reason, issue) {
-                        (Some(feature), reason, Some(issue)) => {
-                            stab = Some(Stability {
-                                level: Unstable {
-                                    reason,
-                                    issue: {
-                                        if let Ok(issue) = issue.as_str().parse() {
-                                            issue
-                                        } else {
-                                            span_err!(diagnostic, attr.span(), E0545,
-                                                      "incorrect 'issue'");
-                                            continue
-                                        }
-                                    }
-                                },
-                                feature,
-                                rustc_depr: None,
-                                rustc_const_unstable: None,
-                            })
-                        }
-                        (None, _, _) => {
-                            handle_errors(diagnostic, attr.span(), AttrError::MissingFeature);
-                            continue
-                        }
-                        _ => {
-                            span_err!(diagnostic, attr.span(), E0547, "missing 'issue'");
-                            continue
-                        }
-                    }
-                }
-                "stable" => {
-                    if stab.is_some() {
-                        handle_errors(diagnostic, attr.span(), AttrError::MultipleStabilityLevels);
-                        break
-                    }
-
-                    let mut feature = None;
-                    let mut since = None;
-                    for meta in metas {
-                        if let NestedMetaItemKind::MetaItem(ref mi) = meta.node {
-                            match &*mi.name().as_str() {
-                                "feature" => if !get(mi, &mut feature) { continue 'outer },
-                                "since" => if !get(mi, &mut since) { continue 'outer },
-                                _ => {
-                                    handle_errors(diagnostic, meta.span,
-                                                  AttrError::UnknownMetaItem(mi.name()));
-                                    continue 'outer
-                                }
-                            }
-                        } else {
-                            handle_errors(diagnostic, meta.span, AttrError::UnsupportedLiteral);
-                            continue 'outer
-                        }
-                    }
-
-                    match (feature, since) {
-                        (Some(feature), Some(since)) => {
-                            stab = Some(Stability {
-                                level: Stable {
-                                    since,
-                                },
-                                feature,
-                                rustc_depr: None,
-                                rustc_const_unstable: None,
-                            })
-                        }
-                        (None, _) => {
-                            handle_errors(diagnostic, attr.span(), AttrError::MissingFeature);
-                            continue
-                        }
-                        _ => {
-                            handle_errors(diagnostic, attr.span(), AttrError::MissingSince);
-                            continue
-                        }
-                    }
-                }
-                _ => unreachable!()
-            }
-        } else {
-            span_err!(diagnostic, attr.span(), E0548, "incorrect stability attribute type");
-            continue
-        }
-    }
-
-    // Merge the deprecation info into the stability info
-    if let Some(rustc_depr) = rustc_depr {
-        if let Some(ref mut stab) = stab {
-            stab.rustc_depr = Some(rustc_depr);
-        } else {
-            span_err!(diagnostic, item_sp, E0549,
-                      "rustc_deprecated attribute must be paired with \
-                       either stable or unstable attribute");
-        }
-    }
-
-    // Merge the const-unstable info into the stability info
-    if let Some(rustc_const_unstable) = rustc_const_unstable {
-        if let Some(ref mut stab) = stab {
-            stab.rustc_const_unstable = Some(rustc_const_unstable);
-        } else {
-            span_err!(diagnostic, item_sp, E0630,
-                      "rustc_const_unstable attribute must be paired with \
-                       either stable or unstable attribute");
-        }
-    }
-
-    stab
-}
-
-fn find_deprecation_generic<'a, I>(diagnostic: &Handler,
-                                   attrs_iter: I,
-                                   item_sp: Span)
-                                   -> Option<Deprecation>
-    where I: Iterator<Item = &'a Attribute>
-{
-    let mut depr: Option<Deprecation> = None;
-
-    'outer: for attr in attrs_iter {
-        if attr.path != "deprecated" {
-            continue
-        }
-
-        mark_used(attr);
-
-        if depr.is_some() {
-            span_err!(diagnostic, item_sp, E0550, "multiple deprecated attributes");
-            break
-        }
-
-        depr = if let Some(metas) = attr.meta_item_list() {
-            let get = |meta: &MetaItem, item: &mut Option<Symbol>| {
-                if item.is_some() {
-                    handle_errors(diagnostic, meta.span, AttrError::MultipleItem(meta.name()));
-                    return false
-                }
-                if let Some(v) = meta.value_str() {
-                    *item = Some(v);
-                    true
-                } else {
-                    span_err!(diagnostic, meta.span, E0551, "incorrect meta item");
-                    false
-                }
-            };
-
-            let mut since = None;
-            let mut note = None;
-            for meta in metas {
-                if let NestedMetaItemKind::MetaItem(ref mi) = meta.node {
-                    match &*mi.name().as_str() {
-                        "since" => if !get(mi, &mut since) { continue 'outer },
-                        "note" => if !get(mi, &mut note) { continue 'outer },
-                        _ => {
-                            handle_errors(diagnostic, meta.span,
-                                          AttrError::UnknownMetaItem(mi.name()));
-                            continue 'outer
-                        }
-                    }
-                } else {
-                    handle_errors(diagnostic, meta.span, AttrError::UnsupportedLiteral);
-                    continue 'outer
-                }
-            }
-
-            Some(Deprecation {since: since, note: note})
-        } else {
-            Some(Deprecation{since: None, note: None})
-        }
-    }
-
-    depr
-}
-
-/// Find the first stability attribute. `None` if none exists.
-pub fn find_stability(diagnostic: &Handler, attrs: &[Attribute],
-                      item_sp: Span) -> Option<Stability> {
-    find_stability_generic(diagnostic, attrs.iter(), item_sp)
-}
-
-/// Find the deprecation attribute. `None` if none exists.
-pub fn find_deprecation(diagnostic: &Handler, attrs: &[Attribute],
-                        item_sp: Span) -> Option<Deprecation> {
-    find_deprecation_generic(diagnostic, attrs.iter(), item_sp)
-}
-
-
-/// Parse #[repr(...)] forms.
-///
-/// Valid repr contents: any of the primitive integral type names (see
-/// `int_type_of_word`, below) to specify enum discriminant type; `C`, to use
-/// the same discriminant size that the corresponding C enum would or C
-/// structure layout, `packed` to remove padding, and `transparent` to elegate representation
-/// concerns to the only non-ZST field.
-pub fn find_repr_attrs(diagnostic: &Handler, attr: &Attribute) -> Vec<ReprAttr> {
-    let mut acc = Vec::new();
-    if attr.path == "repr" {
-        if let Some(items) = attr.meta_item_list() {
-            mark_used(attr);
-            for item in items {
-                if !item.is_meta_item() {
-                    handle_errors(diagnostic, item.span, AttrError::UnsupportedLiteral);
-                    continue
-                }
-
-                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 let Some(h) = hint {
-                        recognised = true;
-                        acc.push(h);
-                    }
-                } else if let Some((name, value)) = item.name_value_literal() {
-                    let parse_alignment = |node: &ast::LitKind| -> Result<u32, &'static str> {
-                        if let ast::LitKind::Int(literal, ast::LitIntType::Unsuffixed) = node {
-                            if literal.is_power_of_two() {
-                                // rustc::ty::layout::Align restricts align to <= 2^29
-                                if *literal <= 1 << 29 {
-                                    Ok(*literal as u32)
-                                } else {
-                                    Err("larger than 2^29")
-                                }
-                            } else {
-                                Err("not a power of two")
-                            }
-                        } else {
-                            Err("not an unsuffixed integer")
-                        }
-                    };
-
-                    let mut literal_error = None;
-                    if name == "align" {
-                        recognised = true;
-                        match parse_alignment(&value.node) {
-                            Ok(literal) => acc.push(ReprAlign(literal)),
-                            Err(message) => literal_error = Some(message)
-                        };
-                    }
-                    else if name == "packed" {
-                        recognised = true;
-                        match parse_alignment(&value.node) {
-                            Ok(literal) => acc.push(ReprPacked(literal)),
-                            Err(message) => literal_error = Some(message)
-                        };
-                    }
-                    if let Some(literal_error) = literal_error {
-                        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 let MetaItemKind::NameValue(ref value) = meta_item.node {
-                                recognised = true;
-                                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_with_applicability(
-                                            item.span,
-                                            "use parentheses instead",
-                                            format!("align({})", int),
-                                            Applicability::MachineApplicable
-                                        );
-                                    }
-                                    ast::LitKind::Str(s, _) => {
-                                        err.span_suggestion_with_applicability(
-                                            item.span,
-                                            "use parentheses instead",
-                                            format!("align({})", s),
-                                            Applicability::MachineApplicable
-                                        );
-                                    }
-                                    _ => {}
-                                }
-                                err.emit();
-                            }
-                        }
-                    }
-                }
-                if !recognised {
-                    // Not a word we recognize
-                    span_err!(diagnostic, item.span, E0552,
-                              "unrecognized representation hint");
-                }
-            }
-        }
-    }
-    acc
-}
-
-fn int_type_of_word(s: &str) -> Option<IntType> {
-    match s {
-        "i8" => Some(SignedInt(ast::IntTy::I8)),
-        "u8" => Some(UnsignedInt(ast::UintTy::U8)),
-        "i16" => Some(SignedInt(ast::IntTy::I16)),
-        "u16" => Some(UnsignedInt(ast::UintTy::U16)),
-        "i32" => Some(SignedInt(ast::IntTy::I32)),
-        "u32" => Some(UnsignedInt(ast::UintTy::U32)),
-        "i64" => Some(SignedInt(ast::IntTy::I64)),
-        "u64" => Some(UnsignedInt(ast::UintTy::U64)),
-        "i128" => Some(SignedInt(ast::IntTy::I128)),
-        "u128" => Some(UnsignedInt(ast::UintTy::U128)),
-        "isize" => Some(SignedInt(ast::IntTy::Isize)),
-        "usize" => Some(UnsignedInt(ast::UintTy::Usize)),
-        _ => None
-    }
-}
-
-#[derive(PartialEq, Debug, RustcEncodable, RustcDecodable, Copy, Clone)]
-pub enum ReprAttr {
-    ReprInt(IntType),
-    ReprC,
-    ReprPacked(u32),
-    ReprSimd,
-    ReprTransparent,
-    ReprAlign(u32),
-}
-
-#[derive(Eq, Hash, PartialEq, Debug, RustcEncodable, RustcDecodable, Copy, Clone)]
-pub enum IntType {
-    SignedInt(ast::IntTy),
-    UnsignedInt(ast::UintTy)
-}
-
-impl IntType {
-    #[inline]
-    pub fn is_signed(self) -> bool {
-        match self {
-            SignedInt(..) => true,
-            UnsignedInt(..) => false
-        }
-    }
-}
-
 impl MetaItem {
     fn tokens(&self) -> TokenStream {
         let mut idents = vec![];