Fix various useless derefs and slicings

Author: oli-obk

src/bootstrap/check.rs

@@ -586,7 +586,7 @@ fn android_copy_libs(build: &Build, compiler: &Compiler, target: &str) {
                       .arg(ADB_TEST_DIR));
 
     let target_dir = format!("{}/{}", ADB_TEST_DIR, target);
-    build.run(Command::new("adb").args(&["shell", "mkdir", &target_dir[..]]));
+    build.run(Command::new("adb").args(&["shell", "mkdir", &target_dir]));
 
     for f in t!(build.sysroot_libdir(compiler, target).read_dir()) {
         let f = t!(f);

src/grammar/verify.rs

@@ -196,7 +196,7 @@ fn parse_antlr_token(s: &str, tokens: &HashMap<String, token::Token>, surrogate_
     let toknum = &s[content_end + 3 .. toknum_end];
 
     let not_found = format!("didn't find token {:?} in the map", toknum);
-    let proto_tok = tokens.get(toknum).expect(&not_found[..]);
+    let proto_tok = tokens.get(toknum).expect(&not_found);
 
     let nm = Symbol::intern(content);
 
@@ -304,14 +304,14 @@ fn main() {
     let mut token_file = File::open(&Path::new(&args.next().unwrap())).unwrap();
     let mut token_list = String::new();
     token_file.read_to_string(&mut token_list).unwrap();
-    let token_map = parse_token_list(&token_list[..]);
+    let token_map = parse_token_list(&token_list);
 
     let stdin = std::io::stdin();
     let lock = stdin.lock();
     let lines = lock.lines();
     let antlr_tokens = lines.map(|l| parse_antlr_token(l.unwrap().trim(),
                                                        &token_map,
-                                                       &surrogate_pairs_pos[..],
+                                                       &surrogate_pairs_pos,
                                                        has_bom));
 
     for antlr_tok in antlr_tokens {

src/libcollections/linked_list.rs

@@ -1376,7 +1376,7 @@ mod tests {
         thread::spawn(move || {
                 check_links(&n);
                 let a: &[_] = &[&1, &2, &3];
-                assert_eq!(a, &n.iter().collect::<Vec<_>>()[..]);
+                assert_eq!(a, &*n.iter().collect::<Vec<_>>());
             })
             .join()
             .ok()

src/libgraphviz/lib.rs

@@ -554,7 +554,7 @@ impl<'a> LabelText<'a> {
     pub fn to_dot_string(&self) -> String {
         match self {
             &LabelStr(ref s) => format!("\"{}\"", s.escape_default()),
-            &EscStr(ref s) => format!("\"{}\"", LabelText::escape_str(&s[..])),
+            &EscStr(ref s) => format!("\"{}\"", LabelText::escape_str(&s)),
             &HtmlStr(ref s) => format!("<{}>", s),
         }
     }
@@ -587,7 +587,7 @@ impl<'a> LabelText<'a> {
         let mut prefix = self.pre_escaped_content().into_owned();
         let suffix = suffix.pre_escaped_content();
         prefix.push_str(r"\n\n");
-        prefix.push_str(&suffix[..]);
+        prefix.push_str(&suffix);
         EscStr(prefix.into_cow())
     }
 }
@@ -878,7 +878,7 @@ mod tests {
         type Node = Node;
         type Edge = &'a Edge;
         fn graph_id(&'a self) -> Id<'a> {
-            Id::new(&self.name[..]).unwrap()
+            Id::new(self.name).unwrap()
         }
         fn node_id(&'a self, n: &Node) -> Id<'a> {
             id_name(n)

src/librustc/ich/fingerprint.rs

@@ -55,7 +55,7 @@ impl Fingerprint {
 impl Encodable for Fingerprint {
     #[inline]
     fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
-        for &byte in &self.0[..] {
+        for &byte in &self.0 {
             s.emit_u8(byte)?;
         }
         Ok(())
@@ -66,7 +66,7 @@ impl Decodable for Fingerprint {
     #[inline]
     fn decode<D: Decoder>(d: &mut D) -> Result<Fingerprint, D::Error> {
         let mut result = Fingerprint([0u8; FINGERPRINT_LENGTH]);
-        for byte in &mut result.0[..] {
+        for byte in &mut result.0 {
             *byte = d.read_u8()?;
         }
         Ok(result)

src/librustc/lint/context.rs

@@ -40,7 +40,6 @@ use std::cmp;
 use std::default::Default as StdDefault;
 use std::mem;
 use std::fmt;
-use std::ops::Deref;
 use syntax::attr;
 use syntax::ast;
 use syntax::symbol::Symbol;
@@ -485,7 +484,7 @@ pub fn raw_struct_lint<'a, S>(sess: &'a Session,
                 Allow => bug!("earlier conditional return should handle Allow case")
             };
             let hyphen_case_lint_name = name.replace("_", "-");
-            if lint_flag_val.as_str().deref() == name {
+            if lint_flag_val.as_str() == name {
                 err.note(&format!("requested on the command line with `{} {}`",
                                   flag, hyphen_case_lint_name));
             } else {
@@ -496,7 +495,7 @@ pub fn raw_struct_lint<'a, S>(sess: &'a Session,
         },
         Node(lint_attr_name, src) => {
             def = Some(src);
-            if lint_attr_name.as_str().deref() != name {
+            if lint_attr_name.as_str() != name {
                 let level_str = level.as_str();
                 err.note(&format!("#[{}({})] implied by #[{}({})]",
                                   level_str, name, level_str, lint_attr_name));

src/librustc/middle/stability.rs

@@ -536,7 +536,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                 if !self.stability.borrow().active_features.contains(feature) {
                     let msg = match *reason {
                         Some(ref r) => format!("use of unstable library feature '{}': {}",
-                                               &feature.as_str(), &r),
+                                               feature.as_str(), &r),
                         None => format!("use of unstable library feature '{}'", &feature)
                     };
                     emit_feature_err(&self.sess.parse_sess, &feature.as_str(), span,

src/librustc_borrowck/borrowck/fragments.rs

@@ -267,11 +267,11 @@ pub fn fixup_fragment_sets<'a, 'tcx>(this: &MoveData<'tcx>, tcx: TyCtxt<'a, 'tcx
     // First, filter out duplicates
     moved.sort();
     moved.dedup();
-    debug!("fragments 1 moved: {:?}", path_lps(&moved[..]));
+    debug!("fragments 1 moved: {:?}", path_lps(&moved));
 
     assigned.sort();
     assigned.dedup();
-    debug!("fragments 1 assigned: {:?}", path_lps(&assigned[..]));
+    debug!("fragments 1 assigned: {:?}", path_lps(&assigned));
 
     // Second, build parents from the moved and assigned.
     for m in &moved {
@@ -291,14 +291,14 @@ pub fn fixup_fragment_sets<'a, 'tcx>(this: &MoveData<'tcx>, tcx: TyCtxt<'a, 'tcx
 
     parents.sort();
     parents.dedup();
-    debug!("fragments 2 parents: {:?}", path_lps(&parents[..]));
+    debug!("fragments 2 parents: {:?}", path_lps(&parents));
 
     // Third, filter the moved and assigned fragments down to just the non-parents
-    moved.retain(|f| non_member(*f, &parents[..]));
-    debug!("fragments 3 moved: {:?}", path_lps(&moved[..]));
+    moved.retain(|f| non_member(*f, &parents));
+    debug!("fragments 3 moved: {:?}", path_lps(&moved));
 
-    assigned.retain(|f| non_member(*f, &parents[..]));
-    debug!("fragments 3 assigned: {:?}", path_lps(&assigned[..]));
+    assigned.retain(|f| non_member(*f, &parents));
+    debug!("fragments 3 assigned: {:?}", path_lps(&assigned));
 
     // Fourth, build the leftover from the moved, assigned, and parents.
     for m in &moved {
@@ -316,16 +316,16 @@ pub fn fixup_fragment_sets<'a, 'tcx>(this: &MoveData<'tcx>, tcx: TyCtxt<'a, 'tcx
 
     unmoved.sort();
     unmoved.dedup();
-    debug!("fragments 4 unmoved: {:?}", frag_lps(&unmoved[..]));
+    debug!("fragments 4 unmoved: {:?}", frag_lps(&unmoved));
 
     // Fifth, filter the leftover fragments down to its core.
     unmoved.retain(|f| match *f {
         AllButOneFrom(_) => true,
-        Just(mpi) => non_member(mpi, &parents[..]) &&
-            non_member(mpi, &moved[..]) &&
-            non_member(mpi, &assigned[..])
+        Just(mpi) => non_member(mpi, &parents) &&
+            non_member(mpi, &moved) &&
+            non_member(mpi, &assigned)
     });
-    debug!("fragments 5 unmoved: {:?}", frag_lps(&unmoved[..]));
+    debug!("fragments 5 unmoved: {:?}", frag_lps(&unmoved));
 
     // Swap contents back in.
     fragments.unmoved_fragments = unmoved;

src/librustc_borrowck/borrowck/mod.rs

@@ -112,7 +112,7 @@ fn borrowck_fn<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, body_id: hir::BodyId) {
                                                  &flowed_moves.move_data,
                                                  owner_id);
 
-    check_loans::check_loans(bccx, &loan_dfcx, &flowed_moves, &all_loans[..], body);
+    check_loans::check_loans(bccx, &loan_dfcx, &flowed_moves, &all_loans, body);
 }
 
 fn build_borrowck_dataflow_data<'a, 'tcx>(this: &mut BorrowckCtxt<'a, 'tcx>,

src/librustc_borrowck/graphviz.rs

@@ -88,7 +88,7 @@ impl<'a, 'tcx> DataflowLabeller<'a, 'tcx> {
                 set.push_str(", ");
             }
             let loan_str = self.borrowck_ctxt.loan_path_to_string(&lp);
-            set.push_str(&loan_str[..]);
+            set.push_str(&loan_str);
             saw_some = true;
             true
         });

src/librustc_const_eval/_match.rs

@@ -680,10 +680,10 @@ fn is_useful_specialized<'p, 'a:'p, 'tcx: 'a>(
     }).collect();
     let wild_patterns: Vec<_> = wild_patterns_owned.iter().collect();
     let matrix = Matrix(m.iter().flat_map(|r| {
-        specialize(cx, &r[..], &ctor, &wild_patterns)
+        specialize(cx, &r, &ctor, &wild_patterns)
     }).collect());
     match specialize(cx, v, &ctor, &wild_patterns) {
-        Some(v) => match is_useful(cx, &matrix, &v[..], witness) {
+        Some(v) => match is_useful(cx, &matrix, &v, witness) {
             UsefulWithWitness(witnesses) => UsefulWithWitness(
                 witnesses.into_iter()
                     .map(|witness| witness.apply_constructor(cx, &ctor, lty))

src/librustc_const_eval/check_match.rs

@@ -311,7 +311,7 @@ fn check_arms<'a, 'tcx>(cx: &mut MatchCheckCtxt<'a, 'tcx>,
         for &(pat, hir_pat) in pats {
             let v = vec![pat];
 
-            match is_useful(cx, &seen, &v[..], LeaveOutWitness) {
+            match is_useful(cx, &seen, &v, LeaveOutWitness) {
                 NotUseful => {
                     match source {
                         hir::MatchSource::IfLetDesugar { .. } => {

src/librustc_data_structures/accumulate_vec.rs

@@ -91,17 +91,17 @@ impl<A: Array> Deref for AccumulateVec<A> {
     type Target = [A::Element];
     fn deref(&self) -> &Self::Target {
         match *self {
-            AccumulateVec::Array(ref v) => &v[..],
-            AccumulateVec::Heap(ref v) => &v[..],
+            AccumulateVec::Array(ref v) => v,
+            AccumulateVec::Heap(ref v) => v,
         }
     }
 }
 
 impl<A: Array> DerefMut for AccumulateVec<A> {
     fn deref_mut(&mut self) -> &mut [A::Element] {
         match *self {
-            AccumulateVec::Array(ref mut v) => &mut v[..],
-            AccumulateVec::Heap(ref mut v) => &mut v[..],
+            AccumulateVec::Array(ref mut v) => v,
+            AccumulateVec::Heap(ref mut v) => v,
         }
     }
 }

src/librustc_data_structures/base_n.rs

@@ -48,7 +48,7 @@ pub fn encode(n: u64, base: u64) -> String {
 #[test]
 fn test_encode() {
     fn test(n: u64, base: u64) {
-        assert_eq!(Ok(n), u64::from_str_radix(&encode(n, base)[..], base as u32));
+        assert_eq!(Ok(n), u64::from_str_radix(&encode(n, base), base as u32));
     }
 
     for base in 2..37 {

src/librustc_data_structures/blake2b.rs

@@ -35,7 +35,7 @@ pub struct Blake2bCtx {
 impl ::std::fmt::Debug for Blake2bCtx {
     fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> Result<(), ::std::fmt::Error> {
         try!(write!(fmt, "hash: "));
-        for v in &self.h[..] {
+        for v in &self.h {
             try!(write!(fmt, "{:x}", v));
         }
         Ok(())

src/librustc_data_structures/indexed_set.rs

@@ -91,13 +91,13 @@ impl<T: Idx> IdxSet<T> {
 impl<T: Idx> Deref for IdxSetBuf<T> {
     type Target = IdxSet<T>;
     fn deref(&self) -> &IdxSet<T> {
-        unsafe { IdxSet::from_slice(&self.bits[..]) }
+        unsafe { IdxSet::from_slice(&self.bits) }
     }
 }
 
 impl<T: Idx> DerefMut for IdxSetBuf<T> {
     fn deref_mut(&mut self) -> &mut IdxSet<T> {
-        unsafe { IdxSet::from_slice_mut(&mut self.bits[..]) }
+        unsafe { IdxSet::from_slice_mut(&mut self.bits) }
     }
 }
 
@@ -135,11 +135,11 @@ impl<T: Idx> IdxSet<T> {
     }
 
     pub fn words(&self) -> &[Word] {
-        &self.bits[..]
+        &self.bits
     }
 
     pub fn words_mut(&mut self) -> &mut [Word] {
-        &mut self.bits[..]
+        &mut self.bits
     }
 
     pub fn clone_from(&mut self, other: &IdxSet<T>) {

src/librustc_driver/lib.rs

@@ -233,7 +233,7 @@ fn make_output(matches: &getopts::Matches) -> (Option<PathBuf>, Option<PathBuf>)
 // Extract input (string or file and optional path) from matches.
 fn make_input(free_matches: &[String]) -> Option<(Input, Option<PathBuf>)> {
     if free_matches.len() == 1 {
-        let ifile = &free_matches[0][..];
+        let ifile = &free_matches[0];
         if ifile == "-" {
             let mut src = String::new();
             io::stdin().read_to_string(&mut src).unwrap();
@@ -800,7 +800,7 @@ Available lint options:
         for lint in lints {
             let name = lint.name_lower().replace("_", "-");
             println!("    {}  {:7.7}  {}",
-                     padded(&name[..]),
+                     padded(&name),
                      lint.default_level.as_str(),
                      lint.desc);
         }
@@ -838,7 +838,7 @@ Available lint options:
                          .map(|x| x.to_string().replace("_", "-"))
                          .collect::<Vec<String>>()
                          .join(", ");
-            println!("    {}  {}", padded(&name[..]), desc);
+            println!("    {}  {}", padded(&name), desc);
         }
         println!("\n");
     };
@@ -945,7 +945,7 @@ pub fn handle_options(args: &[String]) -> Option<getopts::Matches> {
                                                  .into_iter()
                                                  .map(|x| x.opt_group)
                                                  .collect();
-    let matches = match getopts::getopts(&args[..], &all_groups) {
+    let matches = match getopts::getopts(&args, &all_groups) {
         Ok(m) => m,
         Err(f) => early_error(ErrorOutputType::default(), &f.to_string()),
     };
@@ -1084,7 +1084,7 @@ pub fn monitor<F: FnOnce() + Send + 'static>(f: F) {
                       format!("we would appreciate a bug report: {}", BUG_REPORT_URL)];
             for note in &xs {
                 handler.emit(&MultiSpan::new(),
-                             &note[..],
+                             &note,
                              errors::Level::Note);
             }
             if match env::var_os("RUST_BACKTRACE") {

src/librustc_driver/pretty.rs

@@ -589,7 +589,7 @@ impl UserIdentifiedItem {
                                        -> NodesMatchingUII<'a, 'hir> {
         match *self {
             ItemViaNode(node_id) => NodesMatchingDirect(Some(node_id).into_iter()),
-            ItemViaPath(ref parts) => NodesMatchingSuffix(map.nodes_matching_suffix(&parts[..])),
+            ItemViaPath(ref parts) => NodesMatchingSuffix(map.nodes_matching_suffix(&parts)),
         }
     }
 
@@ -600,7 +600,7 @@ impl UserIdentifiedItem {
                                   user_option,
                                   self.reconstructed_input(),
                                   is_wrong_because);
-            sess.fatal(&message[..])
+            sess.fatal(&message)
         };
 
         let mut saw_node = ast::DUMMY_NODE_ID;
@@ -771,7 +771,7 @@ fn print_flowgraph<'a, 'tcx, W: Write>(variants: Vec<borrowck_dot::Variant>,
     fn expand_err_details(r: io::Result<()>) -> io::Result<()> {
         r.map_err(|ioerr| {
             io::Error::new(io::ErrorKind::Other,
-                           &format!("graphviz::render failed: {}", ioerr)[..])
+                           format!("graphviz::render failed: {}", ioerr))
         })
     }
 }

src/librustc_driver/test.rs

@@ -289,7 +289,7 @@ impl<'a, 'gcx, 'tcx> Env<'a, 'gcx, 'tcx> {
 
     pub fn t_param(&self, index: u32) -> Ty<'tcx> {
         let name = format!("T{}", index);
-        self.infcx.tcx.mk_param(index, Symbol::intern(&name[..]))
+        self.infcx.tcx.mk_param(index, Symbol::intern(&name))
     }
 
     pub fn re_early_bound(&self, index: u32, name: &'static str) -> &'tcx ty::Region {

src/librustc_incremental/persist/file_format.rs

@@ -99,9 +99,9 @@ pub fn read_file(sess: &Session, path: &Path) -> io::Result<Option<Vec<u8>>> {
         let rustc_version_str_len = rustc_version_str_len[0] as usize;
         let mut buffer = Vec::with_capacity(rustc_version_str_len);
         buffer.resize(rustc_version_str_len, 0);
-        file.read_exact(&mut buffer[..])?;
+        file.read_exact(&mut buffer)?;
 
-        if &buffer[..] != rustc_version().as_bytes() {
+        if buffer != rustc_version().as_bytes() {
             report_format_mismatch(sess, path, "Different compiler version");
             return Ok(None);
         }

src/librustc_lint/bad_style.rs

@@ -88,7 +88,7 @@ impl NonCamelCaseTypes {
             } else {
                 format!("{} `{}` should have a camel case name such as `{}`", sort, name, c)
             };
-            cx.span_lint(NON_CAMEL_CASE_TYPES, span, &m[..]);
+            cx.span_lint(NON_CAMEL_CASE_TYPES, span, &m);
         }
     }
 }