auto merge of #14696 : jakub-/rust/dead-struct-fields, r=alexcrichton

This uncovered some dead code, most notably in middle/liveness.rs, which I think suggests there must be something fishy with that part of the code.

The #[allow(dead_code)] annotations on some of the fields I am not super happy about but as I understand, marker type may disappear at some point.

40 files changed, 223 insertions, 148 deletions

diff --git a/src/libglob/lib.rs b/src/libglob/lib.rs
index f3e1da77ce5..6d39a332ad9 100644
--- a/src/libglob/lib.rs
+++ b/src/libglob/lib.rs
@@ -44,7 +44,6 @@ use std::string::String;
  * pattern - see the `glob` function for more details.
  */
 pub struct Paths {
-    root: Path,
     dir_patterns: Vec<Pattern>,
     require_dir: bool,
     options: MatchOptions,
@@ -108,7 +107,6 @@ pub fn glob_with(pattern: &str, options: MatchOptions) -> Paths {
             // FIXME: How do we want to handle verbatim paths? I'm inclined to return nothing,
             // since we can't very well find all UNC shares with a 1-letter server name.
             return Paths {
-                root: root,
                 dir_patterns: Vec::new(),
                 require_dir: false,
                 options: options,
@@ -134,7 +132,6 @@ pub fn glob_with(pattern: &str, options: MatchOptions) -> Paths {
     }
 
     Paths {
-        root: root,
         dir_patterns: dir_patterns,
         require_dir: require_dir,
         options: options,
diff --git a/src/libgreen/context.rs b/src/libgreen/context.rs
index 5b1a4a8b80e..e377c203e30 100644
--- a/src/libgreen/context.rs
+++ b/src/libgreen/context.rs
@@ -143,6 +143,7 @@ extern {
 // stacks are disabled.
 
 #[cfg(target_arch = "x86")]
+#[repr(C)]
 struct Registers {
     eax: u32, ebx: u32, ecx: u32, edx: u32,
     ebp: u32, esi: u32, edi: u32, esp: u32,
diff --git a/src/libnative/io/c_win32.rs b/src/libnative/io/c_win32.rs
index 1ec25933eec..e855b8bd4f2 100644
--- a/src/libnative/io/c_win32.rs
+++ b/src/libnative/io/c_win32.rs
@@ -20,6 +20,7 @@ pub static FIONBIO: libc::c_long = 0x8004667e;
 static FD_SETSIZE: uint = 64;
 pub static MSG_DONTWAIT: libc::c_int = 0;
 
+#[repr(C)]
 pub struct WSADATA {
     pub wVersion: libc::WORD,
     pub wHighVersion: libc::WORD,
@@ -32,6 +33,7 @@ pub struct WSADATA {
 
 pub type LPWSADATA = *mut WSADATA;
 
+#[repr(C)]
 pub struct fd_set {
     fd_count: libc::c_uint,
     fd_array: [libc::SOCKET, ..FD_SETSIZE],
diff --git a/src/libnative/io/mod.rs b/src/libnative/io/mod.rs
index 4c5929ef223..4158db7bb8e 100644
--- a/src/libnative/io/mod.rs
+++ b/src/libnative/io/mod.rs
@@ -152,13 +152,13 @@ fn keep_going(data: &[u8], f: |*u8, uint| -> i64) -> i64 {
 /// Implementation of rt::rtio's IoFactory trait to generate handles to the
 /// native I/O functionality.
 pub struct IoFactory {
-    cannot_construct_outside_of_this_module: ()
+    _cannot_construct_outside_of_this_module: ()
 }
 
 impl IoFactory {
     pub fn new() -> IoFactory {
         net::init();
-        IoFactory { cannot_construct_outside_of_this_module: () }
+        IoFactory { _cannot_construct_outside_of_this_module: () }
     }
 }
 
diff --git a/src/libnative/io/net.rs b/src/libnative/io/net.rs
index 24956e514ec..e7effbd6bdb 100644
--- a/src/libnative/io/net.rs
+++ b/src/libnative/io/net.rs
@@ -254,7 +254,10 @@ pub struct TcpStream {
 
 struct Inner {
     fd: sock_t,
-    lock: mutex::NativeMutex,
+
+    // Unused on Linux, where this lock is not necessary.
+    #[allow(dead_code)]
+    lock: mutex::NativeMutex
 }
 
 pub struct Guard<'a> {
diff --git a/src/libnative/io/pipe_unix.rs b/src/libnative/io/pipe_unix.rs
index 7a1134fbe59..1458b475ae9 100644
--- a/src/libnative/io/pipe_unix.rs
+++ b/src/libnative/io/pipe_unix.rs
@@ -58,7 +58,10 @@ fn addr_to_sockaddr_un(addr: &CString) -> IoResult<(libc::sockaddr_storage, uint
 
 struct Inner {
     fd: fd_t,
-    lock: mutex::NativeMutex,
+
+    // Unused on Linux, where this lock is not necessary.
+    #[allow(dead_code)]
+    lock: mutex::NativeMutex
 }
 
 impl Inner {
diff --git a/src/librand/distributions/gamma.rs b/src/librand/distributions/gamma.rs
index cfabf2b08e2..b1a95149830 100644
--- a/src/librand/distributions/gamma.rs
+++ b/src/librand/distributions/gamma.rs
@@ -81,7 +81,6 @@ struct GammaSmallShape {
 /// See `Gamma` for sampling from a Gamma distribution with general
 /// shape parameters.
 struct GammaLargeShape {
-    shape: f64,
     scale: f64,
     c: f64,
     d: f64
@@ -118,7 +117,6 @@ impl GammaLargeShape {
     fn new_raw(shape: f64, scale: f64) -> GammaLargeShape {
         let d = shape - 1. / 3.;
         GammaLargeShape {
-            shape: shape,
             scale: scale,
             c: 1. / (9. * d).sqrt(),
             d: d
diff --git a/src/librustc/front/std_inject.rs b/src/librustc/front/std_inject.rs
index 0514f7de505..0bb1481a402 100644
--- a/src/librustc/front/std_inject.rs
+++ b/src/librustc/front/std_inject.rs
@@ -130,9 +130,7 @@ fn inject_crates_ref(sess: &Session, krate: ast::Crate) -> ast::Crate {
     fold.fold_crate(krate)
 }
 
-struct PreludeInjector<'a> {
-    sess: &'a Session,
-}
+struct PreludeInjector<'a>;
 
 
 impl<'a> fold::Folder for PreludeInjector<'a> {
@@ -223,9 +221,7 @@ impl<'a> fold::Folder for PreludeInjector<'a> {
     }
 }
 
-fn inject_prelude(sess: &Session, krate: ast::Crate) -> ast::Crate {
-    let mut fold = PreludeInjector {
-        sess: sess,
-    };
+fn inject_prelude(_: &Session, krate: ast::Crate) -> ast::Crate {
+    let mut fold = PreludeInjector;
     fold.fold_crate(krate)
 }
diff --git a/src/librustc/metadata/loader.rs b/src/librustc/metadata/loader.rs
index acd96b94f31..cfda97ad26f 100644
--- a/src/librustc/metadata/loader.rs
+++ b/src/librustc/metadata/loader.rs
@@ -86,7 +86,7 @@ pub struct Library {
 }
 
 pub struct ArchiveMetadata {
-    archive: ArchiveRO,
+    _archive: ArchiveRO,
     // See comments in ArchiveMetadata::new for why this is static
     data: &'static [u8],
 }
@@ -487,7 +487,7 @@ impl ArchiveMetadata {
             unsafe { mem::transmute(data) }
         };
         Some(ArchiveMetadata {
-            archive: ar,
+            _archive: ar,
             data: data,
         })
     }
diff --git a/src/librustc/metadata/tyencode.rs b/src/librustc/metadata/tyencode.rs
index f48dbecc530..363fcf79eb5 100644
--- a/src/librustc/metadata/tyencode.rs
+++ b/src/librustc/metadata/tyencode.rs
@@ -42,8 +42,6 @@ pub struct ctxt<'a> {
 // Extra parameters are for converting to/from def_ids in the string rep.
 // Whatever format you choose should not contain pipe characters.
 pub struct ty_abbrev {
-    pos: uint,
-    len: uint,
     s: String
 }
 
@@ -68,8 +66,6 @@ pub fn enc_ty(w: &mut MemWriter, cx: &ctxt, t: ty::t) {
     if abbrev_len < len {
         // I.e. it's actually an abbreviation.
         cx.abbrevs.borrow_mut().insert(t, ty_abbrev {
-            pos: pos as uint,
-            len: len as uint,
             s: format!("\\#{:x}:{:x}\\#", pos, len)
         });
     }
diff --git a/src/librustc/middle/borrowck/gather_loans/lifetime.rs b/src/librustc/middle/borrowck/gather_loans/lifetime.rs
index 3337a56edf0..dc8567af9ed 100644
--- a/src/librustc/middle/borrowck/gather_loans/lifetime.rs
+++ b/src/librustc/middle/borrowck/gather_loans/lifetime.rs
@@ -29,7 +29,7 @@ pub fn guarantee_lifetime(bccx: &BorrowckCtxt,
                           cause: euv::LoanCause,
                           cmt: mc::cmt,
                           loan_region: ty::Region,
-                          loan_kind: ty::BorrowKind)
+                          _: ty::BorrowKind)
                           -> Result<(),()> {
     debug!("guarantee_lifetime(cmt={}, loan_region={})",
            cmt.repr(bccx.tcx), loan_region.repr(bccx.tcx));
@@ -38,7 +38,6 @@ pub fn guarantee_lifetime(bccx: &BorrowckCtxt,
                                          span: span,
                                          cause: cause,
                                          loan_region: loan_region,
-                                         loan_kind: loan_kind,
                                          cmt_original: cmt.clone()};
     ctxt.check(&cmt, None)
 }
@@ -55,7 +54,6 @@ struct GuaranteeLifetimeContext<'a> {
     span: Span,
     cause: euv::LoanCause,
     loan_region: ty::Region,
-    loan_kind: ty::BorrowKind,
     cmt_original: mc::cmt
 }
 
diff --git a/src/librustc/middle/borrowck/gather_loans/mod.rs b/src/librustc/middle/borrowck/gather_loans/mod.rs
index 003687e7b63..ec362f92441 100644
--- a/src/librustc/middle/borrowck/gather_loans/mod.rs
+++ b/src/librustc/middle/borrowck/gather_loans/mod.rs
@@ -310,7 +310,6 @@ impl<'a> GatherLoanCtxt<'a> {
                 Loan {
                     index: self.all_loans.len(),
                     loan_path: loan_path,
-                    cmt: cmt,
                     kind: req_kind,
                     gen_scope: gen_scope,
                     kill_scope: kill_scope,
@@ -481,8 +480,7 @@ impl<'a> GatherLoanCtxt<'a> {
 /// This visitor walks static initializer's expressions and makes
 /// sure the loans being taken are sound.
 struct StaticInitializerCtxt<'a> {
-    bccx: &'a BorrowckCtxt<'a>,
-    item_ub: ast::NodeId,
+    bccx: &'a BorrowckCtxt<'a>
 }
 
 impl<'a> visit::Visitor<()> for StaticInitializerCtxt<'a> {
@@ -509,8 +507,7 @@ pub fn gather_loans_in_static_initializer(bccx: &mut BorrowckCtxt, expr: &ast::E
     debug!("gather_loans_in_static_initializer(expr={})", expr.repr(bccx.tcx));
 
     let mut sicx = StaticInitializerCtxt {
-        bccx: bccx,
-        item_ub: expr.id,
+        bccx: bccx
     };
 
     sicx.visit_expr(expr, ());
diff --git a/src/librustc/middle/borrowck/gather_loans/restrictions.rs b/src/librustc/middle/borrowck/gather_loans/restrictions.rs
index 552381e4216..7c1f5937472 100644
--- a/src/librustc/middle/borrowck/gather_loans/restrictions.rs
+++ b/src/librustc/middle/borrowck/gather_loans/restrictions.rs
@@ -36,7 +36,6 @@ pub fn compute_restrictions(bccx: &BorrowckCtxt,
         bccx: bccx,
         span: span,
         cause: cause,
-        cmt_original: cmt.clone(),
         loan_region: loan_region,
     };
 
@@ -49,7 +48,6 @@ pub fn compute_restrictions(bccx: &BorrowckCtxt,
 struct RestrictionsContext<'a> {
     bccx: &'a BorrowckCtxt<'a>,
     span: Span,
-    cmt_original: mc::cmt,
     loan_region: ty::Region,
     cause: euv::LoanCause,
 }
diff --git a/src/librustc/middle/borrowck/mod.rs b/src/librustc/middle/borrowck/mod.rs
index 5706d249c46..7aaba22dd84 100644
--- a/src/librustc/middle/borrowck/mod.rs
+++ b/src/librustc/middle/borrowck/mod.rs
@@ -180,7 +180,6 @@ pub enum PartialTotal {
 pub struct Loan {
     index: uint,
     loan_path: Rc<LoanPath>,
-    cmt: mc::cmt,
     kind: ty::BorrowKind,
     restrictions: Vec<Restriction>,
     gen_scope: ast::NodeId,
diff --git a/src/librustc/middle/dead.rs b/src/librustc/middle/dead.rs
index fb19fbd70c6..46899ae19ca 100644
--- a/src/librustc/middle/dead.rs
+++ b/src/librustc/middle/dead.rs
@@ -124,6 +124,32 @@ impl<'a> MarkSymbolVisitor<'a> {
         }
     }
 
+    fn handle_field_access(&mut self, lhs: &ast::Expr, name: &ast::Ident) {
+        match ty::get(ty::expr_ty_adjusted(self.tcx, lhs)).sty {
+            ty::ty_struct(id, _) => {
+                let fields = ty::lookup_struct_fields(self.tcx, id);
+                let field_id = fields.iter()
+                    .find(|field| field.name == name.name).unwrap().id;
+                self.live_symbols.insert(field_id.node);
+            },
+            _ => ()
+        }
+    }
+
+    fn handle_field_pattern_match(&mut self, lhs: &ast::Pat, pats: &[ast::FieldPat]) {
+        match self.tcx.def_map.borrow().get(&lhs.id) {
+            &def::DefStruct(id) | &def::DefVariant(_, id, _) => {
+                let fields = ty::lookup_struct_fields(self.tcx, id);
+                for pat in pats.iter() {
+                    let field_id = fields.iter()
+                        .find(|field| field.name == pat.ident.name).unwrap().id;
+                    self.live_symbols.insert(field_id.node);
+                }
+            }
+            _ => ()
+        }
+    }
+
     fn mark_live_symbols(&mut self) {
         let mut scanned = HashSet::new();
         while self.worklist.len() > 0 {
@@ -147,10 +173,22 @@ impl<'a> MarkSymbolVisitor<'a> {
         match *node {
             ast_map::NodeItem(item) => {
                 match item.node {
+                    ast::ItemStruct(struct_def, _) => {
+                        let has_extern_repr = item.attrs.iter().fold(attr::ReprAny, |acc, attr| {
+                            attr::find_repr_attr(self.tcx.sess.diagnostic(), attr, acc)
+                        }) == attr::ReprExtern;
+                        let live_fields = struct_def.fields.iter().filter(|f| {
+                            has_extern_repr || match f.node.kind {
+                                ast::NamedField(_, ast::Public) => true,
+                                _ => false
+                            }
+                        });
+                        self.live_symbols.extend(live_fields.map(|f| f.node.id));
+                        visit::walk_item(self, item, ());
+                    }
                     ast::ItemFn(..)
                     | ast::ItemTy(..)
                     | ast::ItemEnum(..)
-                    | ast::ItemStruct(..)
                     | ast::ItemStatic(..) => {
                         visit::walk_item(self, item, ());
                     }
@@ -178,18 +216,32 @@ impl<'a> Visitor<()> for MarkSymbolVisitor<'a> {
             ast::ExprMethodCall(..) => {
                 self.lookup_and_handle_method(expr.id, expr.span);
             }
+            ast::ExprField(ref lhs, ref ident, _) => {
+                self.handle_field_access(*lhs, ident);
+            }
             _ => ()
         }
 
         visit::walk_expr(self, expr, ())
     }
 
+    fn visit_pat(&mut self, pat: &ast::Pat, _: ()) {
+        match pat.node {
+            ast::PatStruct(_, ref fields, _) => {
+                self.handle_field_pattern_match(pat, fields.as_slice());
+            }
+            _ => ()
+        }
+
+        visit::walk_pat(self, pat, ())
+    }
+
     fn visit_path(&mut self, path: &ast::Path, id: ast::NodeId, _: ()) {
         self.lookup_and_handle_definition(&id);
         visit::walk_path(self, path, ());
     }
 
-    fn visit_item(&mut self, _item: &ast::Item, _: ()) {
+    fn visit_item(&mut self, _: &ast::Item, _: ()) {
         // Do not recurse into items. These items will be added to the
         // worklist and recursed into manually if necessary.
     }
@@ -317,6 +369,23 @@ struct DeadVisitor<'a> {
 }
 
 impl<'a> DeadVisitor<'a> {
+    fn should_warn_about_field(&mut self, node: &ast::StructField_) -> bool {
+        let (is_named, has_leading_underscore) = match node.ident() {
+            Some(ref ident) => (true, token::get_ident(*ident).get()[0] == ('_' as u8)),
+            _ => (false, false)
+        };
+        let field_type = ty::node_id_to_type(self.tcx, node.id);
+        let is_marker_field = match ty::ty_to_def_id(field_type) {
+            Some(def_id) => self.tcx.lang_items.items().any(|(_, item)| *item == Some(def_id)),
+            _ => false
+        };
+        is_named
+            && !self.symbol_is_live(node.id, None)
+            && !has_leading_underscore
+            && !is_marker_field
+            && !has_allow_dead_code_or_lang_attr(node.attrs.as_slice())
+    }
+
     // id := node id of an item's definition.
     // ctor_id := `Some` if the item is a struct_ctor (tuple struct),
     //            `None` otherwise.
@@ -399,6 +468,14 @@ impl<'a> Visitor<()> for DeadVisitor<'a> {
         visit::walk_block(self, block, ());
     }
 
+    fn visit_struct_field(&mut self, field: &ast::StructField, _: ()) {
+        if self.should_warn_about_field(&field.node) {
+            self.warn_dead_code(field.node.id, field.span, field.node.ident().unwrap());
+        }
+
+        visit::walk_struct_field(self, field, ());
+    }
+
     // Overwrite so that we don't warn the trait method itself.
     fn visit_trait_method(&mut self, trait_method: &ast::TraitMethod, _: ()) {
         match *trait_method {
diff --git a/src/librustc/middle/liveness.rs b/src/librustc/middle/liveness.rs
index 278d5d8187b..a7fd81e9c9a 100644
--- a/src/librustc/middle/liveness.rs
+++ b/src/librustc/middle/liveness.rs
@@ -226,21 +226,12 @@ fn invalid_node() -> LiveNode { LiveNode(uint::MAX) }
 
 struct CaptureInfo {
     ln: LiveNode,
-    is_move: bool,
     var_nid: NodeId
 }
 
-enum LocalKind {
-    FromMatch(BindingMode),
-    FromLetWithInitializer,
-    FromLetNoInitializer
-}
-
 struct LocalInfo {
     id: NodeId,
-    ident: Ident,
-    is_mutbl: bool,
-    kind: LocalKind,
+    ident: Ident
 }
 
 enum VarKind {
@@ -406,23 +397,13 @@ fn visit_fn(ir: &mut IrMaps,
 }
 
 fn visit_local(ir: &mut IrMaps, local: &Local) {
-    pat_util::pat_bindings(&ir.tcx.def_map, local.pat, |bm, p_id, sp, path| {
+    pat_util::pat_bindings(&ir.tcx.def_map, local.pat, |_, p_id, sp, path| {
         debug!("adding local variable {}", p_id);
         let name = ast_util::path_to_ident(path);
         ir.add_live_node_for_node(p_id, VarDefNode(sp));
-        let kind = match local.init {
-          Some(_) => FromLetWithInitializer,
-          None => FromLetNoInitializer
-        };
-        let mutbl = match bm {
-            BindByValue(MutMutable) => true,
-            _ => false
-        };
         ir.add_variable(Local(LocalInfo {
           id: p_id,
-          ident: name,
-          is_mutbl: mutbl,
-          kind: kind
+          ident: name
         }));
     });
     visit::walk_local(ir, local, ());
@@ -434,16 +415,10 @@ fn visit_arm(ir: &mut IrMaps, arm: &Arm) {
             debug!("adding local variable {} from match with bm {:?}",
                    p_id, bm);
             let name = ast_util::path_to_ident(path);
-            let mutbl = match bm {
-                BindByValue(MutMutable) => true,
-                _ => false
-            };
             ir.add_live_node_for_node(p_id, VarDefNode(sp));
             ir.add_variable(Local(LocalInfo {
                 id: p_id,
-                ident: name,
-                is_mutbl: mutbl,
-                kind: FromMatch(bm)
+                ident: name
             }));
         })
     }
@@ -481,27 +456,12 @@ fn visit_expr(ir: &mut IrMaps, expr: &Expr) {
         // in better error messages than just pointing at the closure
         // construction site.
         let mut call_caps = Vec::new();
-        let fv_mode = freevars::get_capture_mode(ir.tcx, expr.id);
         freevars::with_freevars(ir.tcx, expr.id, |freevars| {
             for fv in freevars.iter() {
                 match moved_variable_node_id_from_def(fv.def) {
                     Some(rv) => {
                         let fv_ln = ir.add_live_node(FreeVarNode(fv.span));
-                        let fv_id = fv.def.def_id().node;
-                        let fv_ty = ty::node_id_to_type(ir.tcx, fv_id);
-                        let is_move = match fv_mode {
-                            // var must be dead afterwards
-                            freevars::CaptureByValue => {
-                                ty::type_moves_by_default(ir.tcx, fv_ty)
-                            }
-
-                            // var can still be used
-                            freevars::CaptureByRef => {
-                                false
-                            }
-                        };
                         call_caps.push(CaptureInfo {ln: fv_ln,
-                                                    is_move: is_move,
                                                     var_nid: rv});
                     }
                     None => {}
diff --git a/src/librustc/middle/privacy.rs b/src/librustc/middle/privacy.rs
index fcd6d424659..50cbf6bbaf0 100644
--- a/src/librustc/middle/privacy.rs
+++ b/src/librustc/middle/privacy.rs
@@ -353,7 +353,6 @@ impl<'a> Visitor<()> for EmbargoVisitor<'a> {
 struct PrivacyVisitor<'a> {
     tcx: &'a ty::ctxt,
     curitem: ast::NodeId,
-    in_fn: bool,
     in_foreign: bool,
     parents: NodeMap<ast::NodeId>,
     external_exports: resolve::ExternalExports,
@@ -1445,7 +1444,6 @@ pub fn check_crate(tcx: &ty::ctxt,
     // Use the parent map to check the privacy of everything
     let mut visitor = PrivacyVisitor {
         curitem: ast::DUMMY_NODE_ID,
-        in_fn: false,
         in_foreign: false,
         tcx: tcx,
         parents: visitor.parents,
diff --git a/src/librustc/middle/resolve.rs b/src/librustc/middle/resolve.rs
index 89d37bb98b8..b0a322a9eb7 100644
--- a/src/librustc/middle/resolve.rs
+++ b/src/librustc/middle/resolve.rs
@@ -806,7 +806,6 @@ fn namespace_error_to_str(ns: NamespaceError) -> &'static str {
 /// The main resolver class.
 struct Resolver<'a> {
     session: &'a Session,
-    lang_items: &'a LanguageItems,
 
     graph_root: NameBindings,
 
@@ -843,9 +842,6 @@ struct Resolver<'a> {
     // The idents for the primitive types.
     primitive_type_table: PrimitiveTypeTable,
 
-    // The four namespaces.
-    namespaces: Vec<Namespace> ,
-
     def_map: DefMap,
     export_map2: ExportMap2,
     trait_map: TraitMap,
@@ -902,7 +898,7 @@ impl<'a, 'b> Visitor<()> for UnusedImportCheckVisitor<'a, 'b> {
 }
 
 impl<'a> Resolver<'a> {
-    fn new(session: &'a Session, lang_items: &'a LanguageItems, crate_span: Span) -> Resolver<'a> {
+    fn new(session: &'a Session, crate_span: Span) -> Resolver<'a> {
         let graph_root = NameBindings::new();
 
         graph_root.define_module(NoParentLink,
@@ -916,7 +912,6 @@ impl<'a> Resolver<'a> {
 
         Resolver {
             session: session,
-            lang_items: lang_items,
 
             // The outermost module has def ID 0; this is not reflected in the
             // AST.
@@ -941,8 +936,6 @@ impl<'a> Resolver<'a> {
 
             primitive_type_table: PrimitiveTypeTable::new(),
 
-            namespaces: vec!(TypeNS, ValueNS),
-
             def_map: RefCell::new(NodeMap::new()),
             export_map2: RefCell::new(NodeMap::new()),
             trait_map: NodeMap::new(),
@@ -5582,10 +5575,10 @@ pub struct CrateMap {
 
 /// Entry point to crate resolution.
 pub fn resolve_crate(session: &Session,
-                     lang_items: &LanguageItems,
+                     _: &LanguageItems,
                      krate: &Crate)
                   -> CrateMap {
-    let mut resolver = Resolver::new(session, lang_items, krate.span);
+    let mut resolver = Resolver::new(session, krate.span);
     resolver.resolve(krate);
     let Resolver { def_map, export_map2, trait_map, last_private,
                    external_exports, .. } = resolver;
diff --git a/src/librustc/middle/trans/base.rs b/src/librustc/middle/trans/base.rs
index 09f5d2a3507..1cc490bf8f8 100644
--- a/src/librustc/middle/trans/base.rs
+++ b/src/librustc/middle/trans/base.rs
@@ -106,7 +106,9 @@ pub fn init_insn_ctxt() {
     task_local_insn_key.replace(Some(RefCell::new(Vec::new())));
 }
 
-pub struct _InsnCtxt { _x: () }
+pub struct _InsnCtxt {
+    _cannot_construct_outside_of_this_module: ()
+}
 
 #[unsafe_destructor]
 impl Drop for _InsnCtxt {
@@ -124,7 +126,7 @@ pub fn push_ctxt(s: &'static str) -> _InsnCtxt {
         Some(ctx) => ctx.borrow_mut().push(s),
         None => {}
     }
-    _InsnCtxt { _x: () }
+    _InsnCtxt { _cannot_construct_outside_of_this_module: () }
 }
 
 pub struct StatRecorder<'a> {
diff --git a/src/librustc/middle/trans/foreign.rs b/src/librustc/middle/trans/foreign.rs
index 6f217d83a62..565fa88bf43 100644
--- a/src/librustc/middle/trans/foreign.rs
+++ b/src/librustc/middle/trans/foreign.rs
@@ -64,9 +64,6 @@ struct LlvmSignature {
     // function, because the foreign function may opt to return via an
     // out pointer.
     llret_ty: Type,
-
-    // True if *Rust* would use an outpointer for this function.
-    sret: bool,
 }
 
 
@@ -847,8 +844,7 @@ fn foreign_signature(ccx: &CrateContext, fn_sig: &ty::FnSig, arg_tys: &[ty::t])
     let llret_ty = type_of::type_of(ccx, fn_sig.output);
     LlvmSignature {
         llarg_tys: llarg_tys,
-        llret_ty: llret_ty,
-        sret: type_of::return_uses_outptr(ccx, fn_sig.output),
+        llret_ty: llret_ty
     }
 }
 
diff --git a/src/librustc/middle/typeck/coherence.rs b/src/librustc/middle/typeck/coherence.rs
index 99a6aad715c..2c059318478 100644
--- a/src/librustc/middle/typeck/coherence.rs
+++ b/src/librustc/middle/typeck/coherence.rs
@@ -52,9 +52,7 @@ use std::cell::RefCell;
 use std::rc::Rc;
 
 struct UniversalQuantificationResult {
-    monotype: t,
-    type_variables: Vec<ty::t> ,
-    type_param_defs: Rc<Vec<ty::TypeParameterDef> >
+    monotype: t
 }
 
 fn get_base_type(inference_context: &InferCtxt,
@@ -515,9 +513,7 @@ impl<'a> CoherenceChecker<'a> {
         let monotype = polytype.ty.subst(self.crate_context.tcx, &substitutions);
 
         UniversalQuantificationResult {
-            monotype: monotype,
-            type_variables: substitutions.tps,
-            type_param_defs: polytype.generics.type_param_defs.clone()
+            monotype: monotype
         }
     }
 
diff --git a/src/librustc/middle/typeck/variance.rs b/src/librustc/middle/typeck/variance.rs
index 04244ff31a8..92ebf42c7af 100644
--- a/src/librustc/middle/typeck/variance.rs
+++ b/src/librustc/middle/typeck/variance.rs
@@ -271,7 +271,6 @@ enum ParamKind { TypeParam, RegionParam, SelfParam }
 struct InferredInfo<'a> {
     item_id: ast::NodeId,
     kind: ParamKind,
-    index: uint,
     param_id: ast::NodeId,
     term: VarianceTermPtr<'a>,
 }
@@ -310,7 +309,6 @@ impl<'a> TermsContext<'a> {
         let term = self.arena.alloc(|| InferredTerm(inf_index));
         self.inferred_infos.push(InferredInfo { item_id: item_id,
                                                 kind: kind,
-                                                index: index,
                                                 param_id: param_id,
                                                 term: term });
         let newly_added = self.inferred_map.insert(param_id, inf_index);
diff --git a/src/librustc/util/common.rs b/src/librustc/util/common.rs
index 5ddae0c1bfe..08052c03de4 100644
--- a/src/librustc/util/common.rs
+++ b/src/librustc/util/common.rs
@@ -42,23 +42,17 @@ pub fn indent<R>(op: || -> R) -> R {
     r
 }
 
-pub struct _indenter {
-    _i: (),
+pub struct Indenter {
+    _cannot_construct_outside_of_this_module: ()
 }
 
-impl Drop for _indenter {
+impl Drop for Indenter {
     fn drop(&mut self) { debug!("<<"); }
 }
 
-pub fn _indenter(_i: ()) -> _indenter {
-    _indenter {
-        _i: ()
-    }
-}
-
-pub fn indenter() -> _indenter {
+pub fn indenter() -> Indenter {
     debug!(">>");
-    _indenter(())
+    Indenter { _cannot_construct_outside_of_this_module: () }
 }
 
 struct LoopQueryVisitor<'a> {
diff --git a/src/librustdoc/html/markdown.rs b/src/librustdoc/html/markdown.rs
index 260d26c5437..061c05058ae 100644
--- a/src/librustdoc/html/markdown.rs
+++ b/src/librustdoc/html/markdown.rs
@@ -24,6 +24,7 @@
 //! // ... something using html
 //! ```
 
+#![allow(dead_code)]
 #![allow(non_camel_case_types)]
 
 use libc;
diff --git a/src/librustrt/mutex.rs b/src/librustrt/mutex.rs
index fccbe4a15e9..eec19e9d5db 100644
--- a/src/librustrt/mutex.rs
+++ b/src/librustrt/mutex.rs
@@ -298,10 +298,12 @@ mod imp {
         static _PTHREAD_MUTEX_SIG_init: libc::c_long = 0x32AAABA7;
         static _PTHREAD_COND_SIG_init: libc::c_long = 0x3CB0B1BB;
 
+        #[repr(C)]
         pub struct pthread_mutex_t {
             __sig: libc::c_long,
             __opaque: [u8, ..__PTHREAD_MUTEX_SIZE__],
         }
+        #[repr(C)]
         pub struct pthread_cond_t {
             __sig: libc::c_long,
             __opaque: [u8, ..__PTHREAD_COND_SIZE__],
@@ -339,10 +341,12 @@ mod imp {
         #[cfg(target_arch = "mips")]
         static __SIZEOF_PTHREAD_COND_T: uint = 48 - 8;
 
+        #[repr(C)]
         pub struct pthread_mutex_t {
             __align: libc::c_longlong,
             size: [u8, ..__SIZEOF_PTHREAD_MUTEX_T],
         }
+        #[repr(C)]
         pub struct pthread_cond_t {
             __align: libc::c_longlong,
             size: [u8, ..__SIZEOF_PTHREAD_COND_T],
@@ -361,7 +365,9 @@ mod imp {
     mod os {
         use libc;
 
+        #[repr(C)]
         pub struct pthread_mutex_t { value: libc::c_int }
+        #[repr(C)]
         pub struct pthread_cond_t { value: libc::c_int }
 
         pub static PTHREAD_MUTEX_INITIALIZER: pthread_mutex_t = pthread_mutex_t {
diff --git a/src/librustuv/idle.rs b/src/librustuv/idle.rs
index f5cde39bc83..fe8935db2ec 100644
--- a/src/librustuv/idle.rs
+++ b/src/librustuv/idle.rs
@@ -18,7 +18,6 @@ use std::rt::rtio::{Callback, PausableIdleCallback};
 pub struct IdleWatcher {
     handle: *uvll::uv_idle_t,
     idle_flag: bool,
-    closed: bool,
     callback: Box<Callback:Send>,
 }
 
@@ -31,7 +30,6 @@ impl IdleWatcher {
         let me = box IdleWatcher {
             handle: handle,
             idle_flag: false,
-            closed: false,
             callback: cb,
         };
         return me.install();
diff --git a/src/librustuv/net.rs b/src/librustuv/net.rs
index e7bdc25a1fd..47b321b068b 100644
--- a/src/librustuv/net.rs
+++ b/src/librustuv/net.rs
@@ -165,7 +165,6 @@ pub struct TcpWatcher {
 pub struct TcpListener {
     home: HomeHandle,
     handle: *uvll::uv_pipe_t,
-    closing_task: Option<BlockedTask>,
     outgoing: Sender<Result<Box<rtio::RtioTcpStream:Send>, IoError>>,
     incoming: Receiver<Result<Box<rtio::RtioTcpStream:Send>, IoError>>,
 }
@@ -358,7 +357,6 @@ impl TcpListener {
         let l = box TcpListener {
             home: io.make_handle(),
             handle: handle,
-            closing_task: None,
             outgoing: tx,
             incoming: rx,
         };
diff --git a/src/librustuv/uvll.rs b/src/librustuv/uvll.rs
index f6c6d6c9068..a6193dd9379 100644
--- a/src/librustuv/uvll.rs
+++ b/src/librustuv/uvll.rs
@@ -136,6 +136,7 @@ pub struct uv_process_options_t {
 
 // These fields are private because they must be interfaced with through the
 // functions below.
+#[repr(C)]
 pub struct uv_stdio_container_t {
     flags: libc::c_int,
     stream: *uv_stream_t,
diff --git a/src/libstd/collections/hashmap.rs b/src/libstd/collections/hashmap.rs
index a780b63bfd0..34851265409 100644
--- a/src/libstd/collections/hashmap.rs
+++ b/src/libstd/collections/hashmap.rs
@@ -393,7 +393,7 @@ mod table {
         }
 
         pub fn move_iter(self) -> MoveEntries<K, V> {
-            MoveEntries { table: self, idx: 0, elems_seen: 0 }
+            MoveEntries { table: self, idx: 0 }
         }
     }
 
@@ -428,8 +428,7 @@ mod table {
     /// Iterator over the entries in a table, consuming the table.
     pub struct MoveEntries<K, V> {
         table: RawTable<K, V>,
-        idx: uint,
-        elems_seen: uint,
+        idx: uint
     }
 
     impl<'a, K, V> Iterator<(&'a K, &'a V)> for Entries<'a, K, V> {
diff --git a/src/libstd/rt/backtrace.rs b/src/libstd/rt/backtrace.rs
index 423f372f018..a1372b51d47 100644
--- a/src/libstd/rt/backtrace.rs
+++ b/src/libstd/rt/backtrace.rs
@@ -325,6 +325,7 @@ mod imp {
     #[cfg(target_os = "macos")]
     fn print(w: &mut Writer, idx: int, addr: *libc::c_void) -> IoResult<()> {
         use intrinsics;
+        #[repr(C)]
         struct Dl_info {
             dli_fname: *libc::c_char,
             dli_fbase: *libc::c_void,
diff --git a/src/libstd/task.rs b/src/libstd/task.rs
index 9ee62ee3d81..a4e1ad84252 100644
--- a/src/libstd/task.rs
+++ b/src/libstd/task.rs
@@ -84,7 +84,7 @@ pub struct TaskBuilder {
     /// Options to spawn the new task with
     pub opts: TaskOpts,
     gen_body: Option<proc(v: proc():Send):Send -> proc():Send>,
-    nocopy: Option<marker::NoCopy>,
+    nocopy: marker::NoCopy,
 }
 
 impl TaskBuilder {
@@ -94,7 +94,7 @@ impl TaskBuilder {
         TaskBuilder {
             opts: TaskOpts::new(),
             gen_body: None,
-            nocopy: None,
+            nocopy: marker::NoCopy,
         }
     }
 
diff --git a/src/libsync/raw.rs b/src/libsync/raw.rs
index 8fd10cdfa8b..821afeaa1f2 100644
--- a/src/libsync/raw.rs
+++ b/src/libsync/raw.rs
@@ -355,7 +355,7 @@ pub struct Semaphore {
 /// dropped, this value will release the resource back to the semaphore.
 #[must_use]
 pub struct SemaphoreGuard<'a> {
-    guard: SemGuard<'a, ()>,
+    _guard: SemGuard<'a, ()>,
 }
 
 impl Semaphore {
@@ -375,7 +375,7 @@ impl Semaphore {
     /// Acquire a resource of this semaphore, returning an RAII guard which will
     /// release the resource when dropped.
     pub fn access<'a>(&'a self) -> SemaphoreGuard<'a> {
-        SemaphoreGuard { guard: self.sem.access() }
+        SemaphoreGuard { _guard: self.sem.access() }
     }
 }
 
@@ -398,7 +398,7 @@ pub struct Mutex {
 /// corresponding mutex is also unlocked.
 #[must_use]
 pub struct MutexGuard<'a> {
-    guard: SemGuard<'a, Vec<WaitQueue>>,
+    _guard: SemGuard<'a, Vec<WaitQueue>>,
     /// Inner condition variable which is connected to the outer mutex, and can
     /// be used for atomic-unlock-and-deschedule.
     pub cond: Condvar<'a>,
@@ -421,7 +421,7 @@ impl Mutex {
     /// also be accessed through the returned guard.
     pub fn lock<'a>(&'a self) -> MutexGuard<'a> {
         let SemCondGuard { guard, cvar } = self.sem.access_cond();
-        MutexGuard { guard: guard, cond: cvar }
+        MutexGuard { _guard: guard, cond: cvar }
     }
 }
 
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 9c3960d0f06..2f5459b6f2e 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -1053,6 +1053,15 @@ pub struct StructField_ {
     pub attrs: Vec<Attribute>,
 }
 
+impl StructField_ {
+    pub fn ident(&self) -> Option<Ident> {
+        match self.kind {
+            NamedField(ref ident, _) => Some(ident.clone()),
+            UnnamedField(_) => None
+        }
+    }
+}
+
 pub type StructField = Spanned<StructField_>;
 
 #[deriving(Clone, PartialEq, Eq, Encodable, Decodable, Hash)]
diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index 7b25f4db980..14769e3e510 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -21,11 +21,6 @@ use parse::token::special_idents;
 use parse::token::InternedString;
 use parse::token;
 
-pub struct Field {
-    ident: ast::Ident,
-    ex: @ast::Expr
-}
-
 // Transitional reexports so qquote can find the paths it is looking for
 mod syntax {
     pub use ext;
@@ -1000,9 +995,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
     }
 }
 
-struct Duplicator<'a> {
-    cx: &'a ExtCtxt<'a>,
-}
+struct Duplicator<'a>;
 
 impl<'a> Folder for Duplicator<'a> {
     fn new_id(&mut self, _: NodeId) -> NodeId {
@@ -1021,10 +1014,8 @@ pub trait Duplicate {
 }
 
 impl Duplicate for @ast::Expr {
-    fn duplicate(&self, cx: &ExtCtxt) -> @ast::Expr {
-        let mut folder = Duplicator {
-            cx: cx,
-        };
+    fn duplicate(&self, _: &ExtCtxt) -> @ast::Expr {
+        let mut folder = Duplicator;
         folder.fold_expr(*self)
     }
 }
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index f22b24b5a29..7cdc93c7314 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -19,7 +19,6 @@ use codemap::{CodeMap, BytePos};
 use codemap;
 use diagnostic;
 use parse::classify::expr_is_simple_block;
-use parse::token::IdentInterner;
 use parse::token;
 use parse::lexer::comments;
 use parse;
@@ -30,7 +29,6 @@ use print::pp;
 use std::io::{IoResult, MemWriter};
 use std::io;
 use std::mem;
-use std::rc::Rc;
 use std::str;
 use std::string::String;
 
@@ -58,7 +56,6 @@ pub struct CurrentCommentAndLiteral {
 pub struct State<'a> {
     pub s: pp::Printer,
     cm: Option<&'a CodeMap>,
-    intr: Rc<token::IdentInterner>,
     comments: Option<Vec<comments::Comment> >,
     literals: Option<Vec<comments::Literal> >,
     cur_cmnt_and_lit: CurrentCommentAndLiteral,
@@ -76,7 +73,6 @@ pub fn rust_printer_annotated<'a>(writer: Box<io::Writer>,
     State {
         s: pp::mk_printer(writer, default_columns),
         cm: None,
-        intr: token::get_ident_interner(),
         comments: None,
         literals: None,
         cur_cmnt_and_lit: CurrentCommentAndLiteral {
@@ -111,7 +107,6 @@ pub fn print_crate<'a>(cm: &'a CodeMap,
     let mut s = State {
         s: pp::mk_printer(out, default_columns),
         cm: Some(cm),
-        intr: token::get_ident_interner(),
         comments: Some(cmnts),
         // If the code is post expansion, don't use the table of
         // literals, since it doesn't correspond with the literals
diff --git a/src/test/compile-fail/lint-dead-code-1.rs b/src/test/compile-fail/lint-dead-code-1.rs
index 10734f1f243..bca2a5d7edc 100644
--- a/src/test/compile-fail/lint-dead-code-1.rs
+++ b/src/test/compile-fail/lint-dead-code-1.rs
@@ -39,7 +39,10 @@ static STATIC_USED_IN_ENUM_DISCRIMINANT: uint = 10;
 pub type typ = *UsedStruct4;
 pub struct PubStruct();
 struct PrivStruct; //~ ERROR: code is never used
-struct UsedStruct1 { x: int }
+struct UsedStruct1 {
+    #[allow(dead_code)]
+    x: int
+}
 struct UsedStruct2(int);
 struct UsedStruct3;
 struct UsedStruct4;
@@ -53,6 +56,7 @@ struct StructUsedAsField;
 struct StructUsedInEnum;
 struct StructUsedInGeneric;
 pub struct PubStruct2 {
+    #[allow(dead_code)]
     struct_used_as_field: *StructUsedAsField
 }
 
diff --git a/src/test/compile-fail/lint-dead-code-4.rs b/src/test/compile-fail/lint-dead-code-4.rs
new file mode 100644
index 00000000000..718af1841b6
--- /dev/null
+++ b/src/test/compile-fail/lint-dead-code-4.rs
@@ -0,0 +1,67 @@
+// Copyright 2013 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.
+
+#![feature(struct_variant)]
+#![allow(unused_variable)]
+#![allow(non_camel_case_types)]
+#![deny(dead_code)]
+
+extern crate libc;
+
+use std::num;
+
+struct Foo {
+    x: uint,
+    b: bool, //~ ERROR: code is never used
+    marker: std::kinds::marker::NoCopy
+}
+
+fn field_read(f: Foo) -> uint {
+    num::pow(f.x, 2)
+}
+
+enum XYZ {
+    X,
+    Y {
+        a: String,
+        b: int //~ ERROR: code is never used
+    },
+    Z
+}
+
+fn field_match_in_patterns(b: XYZ) -> String {
+    match b {
+        Y { a: a, .. } => a,
+        _ => "".to_string()
+    }
+}
+
+struct Bar {
+    x: uint, //~ ERROR: code is never used
+    b: bool,
+    _guard: ()
+}
+
+#[repr(C)]
+struct Baz {
+    x: libc::c_uint
+}
+
+fn field_match_in_let(f: Bar) -> bool {
+    let Bar { b, .. } = f;
+    b
+}
+
+fn main() {
+    field_read(Foo { x: 1, b: false, marker: std::kinds::marker::NoCopy });
+    field_match_in_patterns(Z);
+    field_match_in_let(Bar { x: 42u, b: true, _guard: () });
+    let _ = Baz { x: 0 };
+}
diff --git a/src/test/compile-fail/lint-managed-heap-memory.rs b/src/test/compile-fail/lint-managed-heap-memory.rs
index d9a79d75975..ff382cb46c7 100644
--- a/src/test/compile-fail/lint-managed-heap-memory.rs
+++ b/src/test/compile-fail/lint-managed-heap-memory.rs
@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![allow(dead_code)]
 #![feature(managed_boxes)]
 #![forbid(managed_heap_memory)]
 
diff --git a/src/test/compile-fail/lint-owned-heap-memory.rs b/src/test/compile-fail/lint-owned-heap-memory.rs
index c9688ad49d7..8f20999a56c 100644
--- a/src/test/compile-fail/lint-owned-heap-memory.rs
+++ b/src/test/compile-fail/lint-owned-heap-memory.rs
@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![allow(dead_code)]
 #![forbid(owned_heap_memory)]
 
 
diff --git a/src/test/compile-fail/lint-uppercase-variables.rs b/src/test/compile-fail/lint-uppercase-variables.rs
index 386b4019485..f1b36d719e9 100644
--- a/src/test/compile-fail/lint-uppercase-variables.rs
+++ b/src/test/compile-fail/lint-uppercase-variables.rs
@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![allow(dead_code)]
 #![deny(uppercase_variables)]
 
 use std::io::File;