Moved and refactored ThinAttributes

src/librustc/lint/context.rs

@@ -41,7 +41,8 @@ use syntax::ast_util::{self, IdVisitingOperation};
 use syntax::attr::{self, AttrMetaMethods};
 use syntax::codemap::Span;
 use syntax::parse::token::InternedString;
-use syntax::ast::{self, ThinAttributesExt};
+use syntax::ast;
+use syntax::attr::ThinAttributesExt;
 use rustc_front::hir;
 use rustc_front::util;
 use rustc_front::intravisit as hir_visit;
@@ -674,7 +675,7 @@ impl<'a, 'tcx, 'v> hir_visit::Visitor<'v> for LateContext<'a, 'tcx> {
     }
 
     fn visit_expr(&mut self, e: &hir::Expr) {
-        self.with_lint_attrs(e.attrs.as_attrs(), |cx| {
+        self.with_lint_attrs(e.attrs.as_attr_slice(), |cx| {
             run_lints!(cx, check_expr, late_passes, e);
             hir_visit::walk_expr(cx, e);
         })
@@ -737,7 +738,7 @@ impl<'a, 'tcx, 'v> hir_visit::Visitor<'v> for LateContext<'a, 'tcx> {
     }
 
     fn visit_local(&mut self, l: &hir::Local) {
-        self.with_lint_attrs(l.attrs.as_attrs(), |cx| {
+        self.with_lint_attrs(l.attrs.as_attr_slice(), |cx| {
             run_lints!(cx, check_local, late_passes, l);
             hir_visit::walk_local(cx, l);
         })

src/librustc_front/fold.rs

@@ -13,7 +13,8 @@
 
 use hir::*;
 use syntax::ast::{Ident, Name, NodeId, DUMMY_NODE_ID, Attribute, Attribute_, MetaItem};
-use syntax::ast::{MetaWord, MetaList, MetaNameValue, ThinAttributesExt};
+use syntax::ast::{MetaWord, MetaList, MetaNameValue};
+use syntax::attr::ThinAttributesExt;
 use hir;
 use syntax::codemap::{respan, Span, Spanned};
 use syntax::owned_slice::OwnedSlice;
@@ -508,7 +509,7 @@ pub fn noop_fold_local<T: Folder>(l: P<Local>, fld: &mut T) -> P<Local> {
             pat: fld.fold_pat(pat),
             init: init.map(|e| fld.fold_expr(e)),
             span: fld.new_span(span),
-            attrs: attrs.map_opt_attrs(|attrs| fold_attrs(attrs, fld)),
+            attrs: attrs.map_thin_attrs(|attrs| fold_attrs(attrs, fld)),
         }
     })
 }
@@ -1172,7 +1173,7 @@ pub fn noop_fold_expr<T: Folder>(Expr { id, node, span, attrs }: Expr, folder: &
             }
         },
         span: folder.new_span(span),
-        attrs: attrs.map_opt_attrs(|attrs| fold_attrs(attrs, folder)),
+        attrs: attrs.map_thin_attrs(|attrs| fold_attrs(attrs, folder)),
     }
 }
 

src/librustc_front/hir.rs

@@ -41,7 +41,7 @@ use syntax::codemap::{self, Span, Spanned, DUMMY_SP, ExpnId};
 use syntax::abi::Abi;
 use syntax::ast::{Name, Ident, NodeId, DUMMY_NODE_ID, TokenTree, AsmDialect};
 use syntax::ast::{Attribute, Lit, StrStyle, FloatTy, IntTy, UintTy, CrateConfig};
-use syntax::ast::ThinAttributes;
+use syntax::attr::ThinAttributes;
 use syntax::owned_slice::OwnedSlice;
 use syntax::parse::token::InternedString;
 use syntax::ptr::P;

src/librustc_front/lowering.rs

@@ -66,6 +66,7 @@ use hir;
 use std::collections::BTreeMap;
 use std::collections::HashMap;
 use syntax::ast::*;
+use syntax::attr::{ThinAttributes, ThinAttributesExt};
 use syntax::ptr::P;
 use syntax::codemap::{respan, Spanned, Span};
 use syntax::owned_slice::OwnedSlice;
@@ -1219,8 +1220,7 @@ pub fn lower_expr(lctx: &LoweringContext, e: &Expr) -> P<hir::Expr> {
                 // merge attributes into the inner expression.
                 return lower_expr(lctx, ex).map(|mut ex| {
                     ex.attrs.update(|attrs| {
-                        // FIXME: Badly named
+                        attrs.prepend(e.attrs.clone())
-                        attrs.prepend_outer(e.attrs.clone())
                     });
                     ex
                 });

src/libsyntax/ast.rs

@@ -45,6 +45,7 @@ pub use self::ViewPath_::*;
 pub use self::Visibility::*;
 pub use self::PathParameters::*;
 
+use attr::ThinAttributes;
 use codemap::{Span, Spanned, DUMMY_SP, ExpnId};
 use abi::Abi;
 use ast_util;
@@ -1952,98 +1953,6 @@ pub struct MacroDef {
     pub body: Vec<TokenTree>,
 }
 
-/// A list of attributes, behind a optional box as
-/// a space optimization.
-pub type ThinAttributes = Option<Box<Vec<Attribute>>>;
-
-pub trait ThinAttributesExt {
-    fn map_opt_attrs<F>(self, f: F) -> Self
-        where F: FnOnce(Vec<Attribute>) -> Vec<Attribute>;
-    fn prepend_outer(mut self, attrs: Self) -> Self;
-    fn append_inner(mut self, attrs: Self) -> Self;
-    fn update<F>(&mut self, f: F)
-        where Self: Sized,
-              F: FnOnce(Self) -> Self;
-    fn as_attrs(&self) -> &[Attribute];
-    fn into_attrs(self) -> Vec<Attribute>;
-}
-
-// FIXME: Rename inner/outer
-// FIXME: Rename opt_attrs
-
-impl ThinAttributesExt for ThinAttributes {
-    fn map_opt_attrs<F>(self, f: F) -> Self
-        where F: FnOnce(Vec<Attribute>) -> Vec<Attribute> {
-
-        // This is kinda complicated... Ensure the function is
-        // always called, and that None inputs or results are
-        // correctly handled.
-        if let Some(mut b) = self {
-            use std::mem::replace;
-
-            let vec = replace(&mut *b, Vec::new());
-            let vec = f(vec);
-            if vec.len() == 0 {
-                None
-            } else {
-                replace(&mut*b, vec);
-                Some(b)
-            }
-        } else {
-            f(Vec::new()).into_opt_attrs()
-        }
-    }
-
-    fn prepend_outer(self, attrs: ThinAttributes) -> Self {
-        attrs.map_opt_attrs(|mut attrs| {
-            attrs.extend(self.into_attrs());
-            attrs
-        })
-    }
-
-    fn append_inner(self, attrs: ThinAttributes) -> Self {
-        self.map_opt_attrs(|mut self_| {
-            self_.extend(attrs.into_attrs());
-            self_
-        })
-    }
-
-    fn update<F>(&mut self, f: F)
-        where Self: Sized,
-              F: FnOnce(ThinAttributes) -> ThinAttributes
-    {
-        let self_ = f(self.take());
-        *self = self_;
-    }
-
-    fn as_attrs(&self) -> &[Attribute] {
-        match *self {
-            Some(ref b) => b,
-            None => &[],
-        }
-    }
-
-    fn into_attrs(self) -> Vec<Attribute> {
-        match self {
-            Some(b) => *b,
-            None => Vec::new(),
-        }
-    }
-}
-
-pub trait AttributesExt {
-    fn into_opt_attrs(self) -> ThinAttributes;
-}
-impl AttributesExt for Vec<Attribute> {
-    fn into_opt_attrs(self) -> ThinAttributes {
-        if self.len() == 0 {
-            None
-        } else {
-            Some(Box::new(self))
-        }
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use serialize;

src/libsyntax/attr.rs

@@ -16,8 +16,8 @@ pub use self::IntType::*;
 
 use ast;
 use ast::{AttrId, Attribute, Attribute_, MetaItem, MetaWord, MetaNameValue, MetaList};
-use ast::{Stmt, StmtDecl, StmtExpr, StmtMac, StmtSemi, DeclItem, DeclLocal, ThinAttributes};
+use ast::{Stmt, StmtDecl, StmtExpr, StmtMac, StmtSemi, DeclItem, DeclLocal};
-use ast::{Expr, ThinAttributesExt, Item, Local, Decl};
+use ast::{Expr, Item, Local, Decl};
 use codemap::{Span, Spanned, spanned, dummy_spanned};
 use codemap::BytePos;
 use diagnostic::SpanHandler;
@@ -723,6 +723,96 @@ impl IntType {
     }
 }
 
+/// A list of attributes, behind a optional box as
+/// a space optimization.
+pub type ThinAttributes = Option<Box<Vec<Attribute>>>;
+
+pub trait ThinAttributesExt {
+    fn map_thin_attrs<F>(self, f: F) -> Self
+        where F: FnOnce(Vec<Attribute>) -> Vec<Attribute>;
+    fn prepend(mut self, attrs: Self) -> Self;
+    fn append(mut self, attrs: Self) -> Self;
+    fn update<F>(&mut self, f: F)
+        where Self: Sized,
+              F: FnOnce(Self) -> Self;
+    fn as_attr_slice(&self) -> &[Attribute];
+    fn into_attr_vec(self) -> Vec<Attribute>;
+}
+
+impl ThinAttributesExt for ThinAttributes {
+    fn map_thin_attrs<F>(self, f: F) -> Self
+        where F: FnOnce(Vec<Attribute>) -> Vec<Attribute> {
+
+        // This is kinda complicated... Ensure the function is
+        // always called, and that None inputs or results are
+        // correctly handled.
+        if let Some(mut b) = self {
+            use std::mem::replace;
+
+            let vec = replace(&mut *b, Vec::new());
+            let vec = f(vec);
+            if vec.len() == 0 {
+                None
+            } else {
+                replace(&mut*b, vec);
+                Some(b)
+            }
+        } else {
+            f(Vec::new()).into_thin_attrs()
+        }
+    }
+
+    fn prepend(self, attrs: ThinAttributes) -> Self {
+        attrs.map_thin_attrs(|mut attrs| {
+            attrs.extend(self.into_attr_vec());
+            attrs
+        })
+    }
+
+    fn append(self, attrs: ThinAttributes) -> Self {
+        self.map_thin_attrs(|mut self_| {
+            self_.extend(attrs.into_attr_vec());
+            self_
+        })
+    }
+
+    fn update<F>(&mut self, f: F)
+        where Self: Sized,
+              F: FnOnce(ThinAttributes) -> ThinAttributes
+    {
+        let self_ = f(self.take());
+        *self = self_;
+    }
+
+    fn as_attr_slice(&self) -> &[Attribute] {
+        match *self {
+            Some(ref b) => b,
+            None => &[],
+        }
+    }
+
+    fn into_attr_vec(self) -> Vec<Attribute> {
+        match self {
+            Some(b) => *b,
+            None => Vec::new(),
+        }
+    }
+}
+
+pub trait AttributesExt {
+    fn into_thin_attrs(self) -> ThinAttributes;
+}
+
+impl AttributesExt for Vec<Attribute> {
+    fn into_thin_attrs(self) -> ThinAttributes {
+        if self.len() == 0 {
+            None
+        } else {
+            Some(Box::new(self))
+        }
+    }
+}
+
 /// A cheap way to add Attributes to an AST node.
 pub trait WithAttrs {
     // FIXME: Could be extended to anything IntoIter<Item=Attribute>
@@ -732,7 +822,7 @@ pub trait WithAttrs {
 impl WithAttrs for P<Expr> {
     fn with_attrs(self, attrs: ThinAttributes) -> Self {
         self.map(|mut e| {
-            e.attrs.update(|a| a.append_inner(attrs));
+            e.attrs.update(|a| a.append(attrs));
             e
         })
     }
@@ -741,7 +831,7 @@ impl WithAttrs for P<Expr> {
 impl WithAttrs for P<Item> {
     fn with_attrs(self, attrs: ThinAttributes) -> Self {
         self.map(|Item { ident, attrs: mut ats, id, node, vis, span }| {
-            ats.extend(attrs.into_attrs());
+            ats.extend(attrs.into_attr_vec());
             Item {
                 ident: ident,
                 attrs: ats,
@@ -757,7 +847,7 @@ impl WithAttrs for P<Item> {
 impl WithAttrs for P<Local> {
     fn with_attrs(self, attrs: ThinAttributes) -> Self {
         self.map(|Local { pat, ty, init, id, span, attrs: mut ats }| {
-            ats.update(|a| a.append_inner(attrs));
+            ats.update(|a| a.append(attrs));
             Local {
                 pat: pat,
                 ty: ty,
@@ -794,7 +884,7 @@ impl WithAttrs for P<Stmt> {
                     StmtExpr(expr, id) => StmtExpr(expr.with_attrs(attrs), id),
                     StmtSemi(expr, id) => StmtSemi(expr.with_attrs(attrs), id),
                     StmtMac(mac, style, mut ats) => {
-                        ats.update(|a| a.append_inner(attrs));
+                        ats.update(|a| a.append(attrs));
                         StmtMac(mac, style, ats)
                     }
                 },

src/libsyntax/config.rs

@@ -54,7 +54,7 @@ impl<'a, F> fold::Folder for Context<'a, F> where F: FnMut(&[ast::Attribute]) ->
         // Anything else is always required, and thus has to error out
         // in case of a cfg attr.
         //
-        // NB: This intentionally not part of the fold_expr() function
+        // NB: This is intentionally not part of the fold_expr() function
         //     in order for fold_opt_expr() to be able to avoid this check
         if let Some(attr) = expr.attrs().iter().find(|a| is_cfg(a)) {
             self.diagnostic.span_err(attr.span,

src/libsyntax/fold.rs

@@ -20,6 +20,7 @@
 
 use ast::*;
 use ast;
+use attr::ThinAttributesExt;
 use ast_util;
 use codemap::{respan, Span, Spanned};
 use owned_slice::OwnedSlice;
@@ -522,7 +523,7 @@ pub fn noop_fold_local<T: Folder>(l: P<Local>, fld: &mut T) -> P<Local> {
         pat: fld.fold_pat(pat),
         init: init.map(|e| fld.fold_expr(e)),
         span: fld.new_span(span),
-        attrs: attrs.map_opt_attrs(|v| fold_attrs(v, fld)),
+        attrs: attrs.map_thin_attrs(|v| fold_attrs(v, fld)),
     })
 }
 
@@ -1339,7 +1340,7 @@ pub fn noop_fold_expr<T: Folder>(Expr {id, node, span, attrs}: Expr, folder: &mu
             ExprParen(ex) => ExprParen(folder.fold_expr(ex))
         },
         span: folder.new_span(span),
-        attrs: attrs.map_opt_attrs(|v| fold_attrs(v, folder)),
+        attrs: attrs.map_thin_attrs(|v| fold_attrs(v, folder)),
     }
 }
 
@@ -1388,7 +1389,7 @@ pub fn noop_fold_stmt<T: Folder>(Spanned {node, span}: Stmt, folder: &mut T)
         StmtMac(mac, semi, attrs) => SmallVector::one(P(Spanned {
             node: StmtMac(mac.map(|m| folder.fold_mac(m)),
                           semi,
-                          attrs.map_opt_attrs(|v| fold_attrs(v, folder))),
+                          attrs.map_thin_attrs(|v| fold_attrs(v, folder))),
             span: span
         }))
     }

src/libsyntax/parse/parser.rs

@@ -56,7 +56,7 @@ use ast::TypeTraitItem;
 use ast::{UnnamedField, UnsafeBlock};
 use ast::{ViewPath, ViewPathGlob, ViewPathList, ViewPathSimple};
 use ast::{Visibility, WhereClause};
-use ast::{ThinAttributes, ThinAttributesExt, AttributesExt};
+use attr::{ThinAttributes, ThinAttributesExt, AttributesExt};
 use ast;
 use ast_util::{self, ident_to_path};
 use codemap::{self, Span, BytePos, Spanned, spanned, mk_sp, CodeMap};
@@ -2053,8 +2053,8 @@ impl<'a> Parser<'a> {
                 try!(self.bump());
 
                 let attrs = try!(self.parse_inner_attributes())
-                    .into_opt_attrs()
+                    .into_thin_attrs()
-                    .prepend_outer(attrs);
+                    .prepend(attrs);
 
                 // (e) is parenthesized e
                 // (e,) is a tuple with only one field, e
@@ -2102,8 +2102,8 @@ impl<'a> Parser<'a> {
                 try!(self.bump());
 
                 let inner_attrs = try!(self.parse_inner_attributes())
-                    .into_opt_attrs();
+                    .into_thin_attrs();
-                attrs.update(|attrs| attrs.append_inner(inner_attrs));
+                attrs.update(|attrs| attrs.append(inner_attrs));
 
                 if self.check(&token::CloseDelim(token::Bracket)) {
                     // Empty vector.
@@ -2257,9 +2257,9 @@ impl<'a> Parser<'a> {
                             let mut fields = Vec::new();
                             let mut base = None;
 
-                            let attrs = attrs.append_inner(
+                            let attrs = attrs.append(
                                 try!(self.parse_inner_attributes())
-                                    .into_opt_attrs());
+                                    .into_thin_attrs());
 
                             while self.token != token::CloseDelim(token::Brace) {
                                 if try!(self.eat(&token::DotDot) ){
@@ -2300,7 +2300,7 @@ impl<'a> Parser<'a> {
         if let Some(attrs) = already_parsed_attrs {
             Ok(attrs)
         } else {
-            self.parse_outer_attributes().map(|a| a.into_opt_attrs())
+            self.parse_outer_attributes().map(|a| a.into_thin_attrs())
         }
     }
 
@@ -2312,8 +2312,8 @@ impl<'a> Parser<'a> {
         let outer_attrs = attrs;
         try!(self.expect(&token::OpenDelim(token::Brace)));
 
-        let inner_attrs = try!(self.parse_inner_attributes()).into_opt_attrs();
+        let inner_attrs = try!(self.parse_inner_attributes()).into_thin_attrs();
-        let attrs = outer_attrs.append_inner(inner_attrs);
+        let attrs = outer_attrs.append(inner_attrs);
 
         let blk = try!(self.parse_block_tail(lo, blk_mode));
         return Ok(self.mk_expr(blk.span.lo, blk.span.hi, ExprBlock(blk), attrs));
@@ -2339,12 +2339,12 @@ impl<'a> Parser<'a> {
         self.parse_dot_or_call_expr_with_(e0)
         .map(|expr|
             expr.map(|mut expr| {
-                expr.attrs.update(|a| a.prepend_outer(attrs));
+                expr.attrs.update(|a| a.prepend(attrs));
                 match expr.node {
                     ExprIf(..) | ExprIfLet(..) => {
-                        if !expr.attrs.as_attrs().is_empty() {
+                        if !expr.attrs.as_attr_slice().is_empty() {
                             // Just point to the first attribute in there...
-                            let span = expr.attrs.as_attrs()[0].span;
+                            let span = expr.attrs.as_attr_slice()[0].span;
 
                             self.span_err(span,
                                 "attributes are not yet allowed on `if` \
@@ -3012,7 +3012,7 @@ impl<'a> Parser<'a> {
         try!(self.expect_keyword(keywords::In));
         let expr = try!(self.parse_expr_res(Restrictions::RESTRICTION_NO_STRUCT_LITERAL, None));
         let (iattrs, loop_block) = try!(self.parse_inner_attrs_and_block());
-        let attrs = attrs.append_inner(iattrs.into_opt_attrs());
+        let attrs = attrs.append(iattrs.into_thin_attrs());
 
         let hi = self.last_span.hi;
 
@@ -3030,7 +3030,7 @@ impl<'a> Parser<'a> {
         }
         let cond = try!(self.parse_expr_res(Restrictions::RESTRICTION_NO_STRUCT_LITERAL, None));
         let (iattrs, body) = try!(self.parse_inner_attrs_and_block());
-        let attrs = attrs.append_inner(iattrs.into_opt_attrs());
+        let attrs = attrs.append(iattrs.into_thin_attrs());
         let hi = body.span.hi;
         return Ok(self.mk_expr(span_lo, hi, ExprWhile(cond, body, opt_ident),
                                attrs));
@@ -3045,7 +3045,7 @@ impl<'a> Parser<'a> {
         try!(self.expect(&token::Eq));
         let expr = try!(self.parse_expr_res(Restrictions::RESTRICTION_NO_STRUCT_LITERAL, None));
         let (iattrs, body) = try!(self.parse_inner_attrs_and_block());
-        let attrs = attrs.append_inner(iattrs.into_opt_attrs());
+        let attrs = attrs.append(iattrs.into_thin_attrs());
         let hi = body.span.hi;
         return Ok(self.mk_expr(span_lo, hi, ExprWhileLet(pat, expr, body, opt_ident), attrs));
     }
@@ -3055,7 +3055,7 @@ impl<'a> Parser<'a> {
                            span_lo: BytePos,
                            attrs: ThinAttributes) -> PResult<P<Expr>> {
         let (iattrs, body) = try!(self.parse_inner_attrs_and_block());
-        let attrs = attrs.append_inner(iattrs.into_opt_attrs());
+        let attrs = attrs.append(iattrs.into_thin_attrs());
         let hi = body.span.hi;
         Ok(self.mk_expr(span_lo, hi, ExprLoop(body, opt_ident), attrs))
     }
@@ -3072,8 +3072,8 @@ impl<'a> Parser<'a> {
             }
             return Err(e)
         }
-        let attrs = attrs.append_inner(
+        let attrs = attrs.append(
-            try!(self.parse_inner_attributes()).into_opt_attrs());
+            try!(self.parse_inner_attributes()).into_thin_attrs());
         let mut arms: Vec<Arm> = Vec::new();
         while self.token != token::CloseDelim(token::Brace) {
             arms.push(try!(self.parse_arm()));
@@ -3596,7 +3596,7 @@ impl<'a> Parser<'a> {
 
         Ok(Some(if self.check_keyword(keywords::Let) {
             try!(self.expect_keyword(keywords::Let));
-            let decl = try!(self.parse_let(attrs.into_opt_attrs()));
+            let decl = try!(self.parse_let(attrs.into_thin_attrs()));
             let hi = decl.span.hi;
             let stmt = StmtDecl(decl, ast::DUMMY_NODE_ID);
             spanned(lo, hi, stmt)
@@ -3654,7 +3654,7 @@ impl<'a> Parser<'a> {
                                              hi,
                                              Mac_ { path: pth, tts: tts, ctxt: EMPTY_CTXT })),
                                    style,
-                                   attrs.into_opt_attrs());
+                                   attrs.into_thin_attrs());
                 spanned(lo, hi, stmt)
             } else {
                 // if it has a special ident, it's definitely an item
@@ -3708,7 +3708,7 @@ impl<'a> Parser<'a> {
 
                     // Remainder are line-expr stmts.
                     let e = try!(self.parse_expr_res(
-                        Restrictions::RESTRICTION_STMT_EXPR, Some(attrs.into_opt_attrs())));
+                        Restrictions::RESTRICTION_STMT_EXPR, Some(attrs.into_thin_attrs())));
                     let hi = e.span.hi;
                     let stmt = StmtExpr(e, ast::DUMMY_NODE_ID);
                     spanned(lo, hi, stmt)

src/libsyntax/print/pprust.rs

@@ -13,7 +13,8 @@ pub use self::AnnNode::*;
 use abi;
 use ast::{self, TokenTree};
 use ast::{RegionTyParamBound, TraitTyParamBound, TraitBoundModifier};
-use ast::{ThinAttributesExt, Attribute};
+use ast::Attribute;
+use attr::ThinAttributesExt;
 use ast_util;
 use util::parser::AssocOp;
 use attr;
@@ -1638,7 +1639,7 @@ impl<'a> State<'a> {
             }
             ast::StmtMac(ref mac, style, ref attrs) => {
                 try!(self.space_if_not_bol());
-                try!(self.print_outer_attributes(attrs.as_attrs()));
+                try!(self.print_outer_attributes(attrs.as_attr_slice()));
                 let delim = match style {
                     ast::MacStmtWithBraces => token::Brace,
                     _ => token::Paren
@@ -1983,7 +1984,7 @@ impl<'a> State<'a> {
                                   is_inline: bool) -> io::Result<()> {
         try!(self.maybe_print_comment(expr.span.lo));
 
-        let attrs = expr.attrs.as_attrs();
+        let attrs = expr.attrs.as_attr_slice();
         if is_inline {
             try!(self.print_outer_attributes_inline(attrs));
         } else {
@@ -2124,7 +2125,7 @@ impl<'a> State<'a> {
                         ast::ExprBlock(ref blk) => {
                             try!(self.print_block_unclosed_with_attrs(
                                 &**blk,
-                                i_expr.attrs.as_attrs()));
+                                i_expr.attrs.as_attr_slice()));
                         }
                         _ => {
                             // this is a bare expression
@@ -2303,7 +2304,7 @@ impl<'a> State<'a> {
         try!(self.maybe_print_comment(decl.span.lo));
         match decl.node {
             ast::DeclLocal(ref loc) => {
-                try!(self.print_outer_attributes(loc.attrs.as_attrs()));
+                try!(self.print_outer_attributes(loc.attrs.as_attr_slice()));
                 try!(self.space_if_not_bol());
                 try!(self.ibox(INDENT_UNIT));
                 try!(self.word_nbsp("let"));

src/libsyntax/visit.rs

@@ -25,6 +25,7 @@
 
 use abi::Abi;
 use ast::*;
+use attr::ThinAttributesExt;
 use codemap::Span;
 
 #[derive(Copy, Clone, PartialEq, Eq)]
@@ -630,7 +631,7 @@ pub fn walk_stmt<'v, V: Visitor<'v>>(visitor: &mut V, statement: &'v Stmt) {
         }
         StmtMac(ref mac, _, ref attrs) => {
             visitor.visit_mac(mac);
-            for attr in attrs.as_attrs() {
+            for attr in attrs.as_attr_slice() {
                 visitor.visit_attribute(attr);
             }
         }