Auto merge of #22561 - richo:as_slice-as_str, r=Manishearth

This may not be quite ready to go out, I fixed some docs but suspect I missed a bunch.

I also wound up fixing a bunch of redundant `[]` suffixes, but on closer inspection I don't believe that can land until after a snapshot.

src/doc/style/errors/ergonomics.md

@@ -22,9 +22,9 @@ fn write_info(info: &Info) -> Result<(), IoError> {
     let mut file = File::open_mode(&Path::new("my_best_friends.txt"),
                                    Open, Write);
     // Early return on error
-    try!(file.write_line(format!("name: {}", info.name).as_slice()));
-    try!(file.write_line(format!("age: {}", info.age).as_slice()));
-    try!(file.write_line(format!("rating: {}", info.rating).as_slice()));
+    try!(file.write_line(&format!("name: {}", info.name)));
+    try!(file.write_line(&format!("age: {}", info.age)));
+    try!(file.write_line(&format!("rating: {}", info.rating)));
     return Ok(());
 }
 ```
@@ -44,15 +44,15 @@ fn write_info(info: &Info) -> Result<(), IoError> {
     let mut file = File::open_mode(&Path::new("my_best_friends.txt"),
                                    Open, Write);
     // Early return on error
-    match file.write_line(format!("name: {}", info.name).as_slice()) {
+    match file.write_line(&format!("name: {}", info.name)) {
         Ok(_) => (),
         Err(e) => return Err(e)
     }
-    match file.write_line(format!("age: {}", info.age).as_slice()) {
+    match file.write_line(&format!("age: {}", info.age)) {
         Ok(_) => (),
         Err(e) => return Err(e)
     }
-    return file.write_line(format!("rating: {}", info.rating).as_slice());
+    return file.write_line(&format!("rating: {}", info.rating));
 }
 ```
 

src/libcollections/fmt.rs

@@ -198,7 +198,7 @@
 //!         // for details, and the function `pad` can be used to pad strings.
 //!         let decimals = f.precision().unwrap_or(3);
 //!         let string = f64::to_str_exact(magnitude, decimals);
-//!         f.pad_integral(true, "", string.as_slice())
+//!         f.pad_integral(true, "", &string)
 //!     }
 //! }
 //!

src/libcollections/string.rs

@@ -139,7 +139,7 @@ impl String {
     /// ```rust
     /// let input = b"Hello \xF0\x90\x80World";
     /// let output = String::from_utf8_lossy(input);
-    /// assert_eq!(output.as_slice(), "Hello \u{FFFD}World");
+    /// assert_eq!(output, "Hello \u{FFFD}World");
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn from_utf8_lossy<'a>(v: &'a [u8]) -> Cow<'a, str> {
@@ -355,7 +355,7 @@ impl String {
     /// ```
     /// let mut s = String::from_str("foo");
     /// s.push_str("bar");
-    /// assert_eq!(s.as_slice(), "foobar");
+    /// assert_eq!(s, "foobar");
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -450,7 +450,7 @@ impl String {
     /// s.push('1');
     /// s.push('2');
     /// s.push('3');
-    /// assert_eq!(s.as_slice(), "abc123");
+    /// assert_eq!(s, "abc123");
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -503,7 +503,7 @@ impl String {
     /// ```
     /// let mut s = String::from_str("hello");
     /// s.truncate(2);
-    /// assert_eq!(s.as_slice(), "he");
+    /// assert_eq!(s, "he");
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -622,7 +622,7 @@ impl String {
     ///     assert!(vec == &[104, 101, 108, 108, 111]);
     ///     vec.reverse();
     /// }
-    /// assert_eq!(s.as_slice(), "olleh");
+    /// assert_eq!(s, "olleh");
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]

src/libcore/result.rs

@@ -178,13 +178,13 @@
 //! fn write_info(info: &Info) -> Result<(), IoError> {
 //!     let mut file = File::open_mode(&Path::new("my_best_friends.txt"), Open, Write);
 //!     // Early return on error
-//!     if let Err(e) = file.write_line(format!("name: {}", info.name).as_slice()) {
+//!     if let Err(e) = file.write_line(&format!("name: {}", info.name)) {
 //!         return Err(e)
 //!     }
-//!     if let Err(e) = file.write_line(format!("age: {}", info.age).as_slice()) {
+//!     if let Err(e) = file.write_line(&format!("age: {}", info.age)) {
 //!         return Err(e)
 //!     }
-//!     return file.write_line(format!("rating: {}", info.rating).as_slice());
+//!     return file.write_line(&format!("rating: {}", info.rating));
 //! }
 //! ```
 //!
@@ -202,9 +202,9 @@
 //! fn write_info(info: &Info) -> Result<(), IoError> {
 //!     let mut file = File::open_mode(&Path::new("my_best_friends.txt"), Open, Write);
 //!     // Early return on error
-//!     try!(file.write_line(format!("name: {}", info.name).as_slice()));
-//!     try!(file.write_line(format!("age: {}", info.age).as_slice()));
-//!     try!(file.write_line(format!("rating: {}", info.rating).as_slice()));
+//!     try!(file.write_line(&format!("name: {}", info.name)));
+//!     try!(file.write_line(&format!("age: {}", info.age)));
+//!     try!(file.write_line(&format!("rating: {}", info.rating)));
 //!     return Ok(());
 //! }
 //! ```

src/libgetopts/lib.rs

@@ -46,7 +46,7 @@
 //!
 //! fn print_usage(program: &str, opts: &[OptGroup]) {
 //!     let brief = format!("Usage: {} [options]", program);
-//!     print!("{}", usage(brief.as_slice(), opts));
+//!     print!("{}", usage(brief, opts));
 //! }
 //!
 //! fn main() {
@@ -63,17 +63,17 @@
 //!         Err(f) => { panic!(f.to_string()) }
 //!     };
 //!     if matches.opt_present("h") {
-//!         print_usage(program.as_slice(), opts);
+//!         print_usage(program, opts);
 //!         return;
 //!     }
 //!     let output = matches.opt_str("o");
 //!     let input = if !matches.free.is_empty() {
 //!         matches.free[0].clone()
 //!     } else {
-//!         print_usage(program.as_slice(), opts);
+//!         print_usage(program, opts);
 //!         return;
 //!     };
-//!     do_work(input.as_slice(), output);
+//!     do_work(input, output);
 //! }
 //! ```
 

src/librustc/metadata/creader.rs

@@ -493,7 +493,7 @@ impl<'a> CrateReader<'a> {
         };
 
         let dylib = library.dylib.clone();
-        let register = should_link && self.existing_match(info.name.as_slice(),
+        let register = should_link && self.existing_match(&info.name,
                                                           None,
                                                           PathKind::Crate).is_none();
         let metadata = if register {

src/librustc/middle/check_match.rs

@@ -276,7 +276,7 @@ fn check_for_static_nan(cx: &MatchCheckCtxt, pat: &Pat) {
                     let subspan = p.span.lo <= err.span.lo && err.span.hi <= p.span.hi;
                     cx.tcx.sess.span_err(err.span,
                                          &format!("constant evaluation error: {}",
-                                                  err.description().as_slice()));
+                                                  err.description()));
                     if !subspan {
                         cx.tcx.sess.span_note(p.span,
                                               "in pattern here")

src/librustc/middle/const_eval.rs

@@ -204,7 +204,7 @@ pub fn const_expr_to_pat(tcx: &ty::ctxt, expr: &Expr, span: Span) -> P<ast::Pat>
 pub fn eval_const_expr(tcx: &ty::ctxt, e: &Expr) -> const_val {
     match eval_const_expr_partial(tcx, e, None) {
         Ok(r) => r,
-        Err(s) => tcx.sess.span_fatal(s.span, s.description().as_slice())
+        Err(s) => tcx.sess.span_fatal(s.span, &s.description())
     }
 }
 
@@ -665,14 +665,14 @@ pub fn compare_lit_exprs<'tcx>(tcx: &ty::ctxt<'tcx>,
     let a = match eval_const_expr_partial(tcx, a, ty_hint) {
         Ok(a) => a,
         Err(e) => {
-            tcx.sess.span_err(a.span, e.description().as_slice());
+            tcx.sess.span_err(a.span, &e.description());
             return None;
         }
     };
     let b = match eval_const_expr_partial(tcx, b, ty_hint) {
         Ok(b) => b,
         Err(e) => {
-            tcx.sess.span_err(b.span, e.description().as_slice());
+            tcx.sess.span_err(b.span, &e.description());
             return None;
         }
     };

src/librustc/middle/ty.rs

@@ -5485,7 +5485,7 @@ pub fn enum_variants<'tcx>(cx: &ctxt<'tcx>, id: ast::DefId)
                                         Err(err) => {
                                             span_err!(cx.sess, err.span, E0305,
                                                       "constant evaluation error: {}",
-                                                      err.description().as_slice());
+                                                      err.description());
                                         }
                                     }
                                 } else {

src/librustc/util/ppaux.rs

@@ -115,7 +115,7 @@ pub fn explain_region_and_span(cx: &ctxt, region: ty::Region)
             region::CodeExtent::Misc(_) => tag,
             region::CodeExtent::DestructionScope(_) => {
                 new_string = format!("destruction scope surrounding {}", tag);
-                new_string.as_slice()
+                &*new_string
             }
             region::CodeExtent::Remainder(r) => {
                 new_string = format!("block suffix following statement {}",

src/librustc_bitflags/lib.rs

@@ -86,7 +86,7 @@
 ///     let mut flags = FLAG_A | FLAG_B;
 ///     flags.clear();
 ///     assert!(flags.is_empty());
-///     assert_eq!(format!("{:?}", flags).as_slice(), "hi!");
+///     assert_eq!(format!("{:?}", flags), "hi!");
 /// }
 /// ```
 ///

src/librustc_borrowck/borrowck/mod.rs

@@ -704,9 +704,9 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
         self.tcx
             .sess
             .span_err(span,
-                      (format!("partial reinitialization of uninitialized \
+                      &format!("partial reinitialization of uninitialized \
                                structure `{}`",
-                               self.loan_path_to_string(lp))).as_slice());
+                               self.loan_path_to_string(lp)));
     }
 
     pub fn report_reassigned_immutable_variable(&self,

src/librustc_lint/builtin.rs

@@ -2080,7 +2080,7 @@ impl LintPass for InvalidNoMangleItems {
                        !cx.exported_items.contains(&it.id) {
                     let msg = format!("static {} is marked #[no_mangle], but not exported",
                                       it.ident);
-                    cx.span_lint(PRIVATE_NO_MANGLE_STATICS, it.span, msg.as_slice());
+                    cx.span_lint(PRIVATE_NO_MANGLE_STATICS, it.span, &msg);
                 }
             },
             ast::ItemConst(..) => {

src/librustc_typeck/astconv.rs

@@ -1404,7 +1404,7 @@ pub fn ast_ty_to_ty<'tcx>(this: &AstConv<'tcx>,
                         ast_ty.span.lo <= r.span.lo && r.span.hi <= ast_ty.span.hi;
                     span_err!(tcx.sess, r.span, E0250,
                               "array length constant evaluation error: {}",
-                              r.description().as_slice());
+                              r.description());
                     if !subspan {
                         span_note!(tcx.sess, ast_ty.span, "for array length here")
                     }

src/librustc_typeck/check/dropck.rs

@@ -298,8 +298,8 @@ fn iterate_over_potentially_unsafe_regions_in_type<'a, 'tcx>(
                 match rcx.tcx().region_maps.opt_encl_scope(scope) {
                     Some(parent_scope) => ty::ReScope(parent_scope),
                     None => rcx.tcx().sess.span_bug(
-                        span, format!("no enclosing scope found for scope: {:?}",
-                                      scope).as_slice()),
+                        span, &format!("no enclosing scope found for scope: {:?}",
+                                       scope)),
                 };
 
             regionck::type_must_outlive(rcx, origin(), typ, parent_region);

src/librustc_typeck/check/mod.rs

@@ -4620,7 +4620,7 @@ pub fn check_enum_variants<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
                         Err(ref err) => {
                             span_err!(ccx.tcx.sess, err.span, E0080,
                                       "constant evaluation error: {}",
-                                      err.description().as_slice());
+                                      err.description());
                         }
                     }
                 },

src/librustc_typeck/check/regionck.rs

@@ -963,9 +963,9 @@ fn check_safety_of_rvalue_destructor_if_necessary<'a, 'tcx>(rcx: &mut Rcx<'a, 't
                     rcx.tcx()
                        .sess
                        .span_bug(span,
-                                 format!("unexpected rvalue region in rvalue \
-                                          destructor safety checking: `{}`",
-                                         region.repr(rcx.tcx())).as_slice());
+                                 &format!("unexpected rvalue region in rvalue \
+                                           destructor safety checking: `{}`",
+                                          region.repr(rcx.tcx())));
                 }
             }
         }

src/librustc_typeck/check/wf.rs

@@ -411,9 +411,9 @@ impl<'ccx, 'tcx> CheckTypeWellFormedVisitor<'ccx, 'tcx> {
             Some(def_id) => {
                 self.tcx().sess.fileline_help(
                     span,
-                    format!("consider removing `{}` or using a marker such as `{}`",
-                            param_name.user_string(self.tcx()),
-                            ty::item_path_str(self.tcx(), def_id)).as_slice());
+                    &format!("consider removing `{}` or using a marker such as `{}`",
+                             param_name.user_string(self.tcx()),
+                             ty::item_path_str(self.tcx(), def_id)));
             }
             None => {
                 // no lang items, no help!

src/librustc_typeck/collect.rs

@@ -1590,8 +1590,8 @@ fn compute_type_scheme_of_item<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
         ast::ItemMac(..) => {
             tcx.sess.span_bug(
                 it.span,
-                format!("compute_type_scheme_of_item: unexpected item type: {:?}",
-                        it.node).as_slice());
+                &format!("compute_type_scheme_of_item: unexpected item type: {:?}",
+                         it.node));
         }
     }
 }

src/libserialize/json.rs

@@ -188,7 +188,7 @@
 //!     let json_str: String = json_obj.to_string();
 //!
 //!     // Deserialize like before
-//!     let decoded: TestStruct = json::decode(json_str.as_slice()).unwrap();
+//!     let decoded: TestStruct = json::decode(json_str)).unwrap();
 //! }
 //! ```
 

src/libstd/env.rs

@@ -780,8 +780,8 @@ mod tests {
             i += 1;
         }
         let n = make_rand_name();
-        set_var(&n, s.as_slice());
-        eq(var_os(&n), Some(s.as_slice()));
+        set_var(&n, &s);
+        eq(var_os(&n), Some(&s));
     }
 
     #[test]
@@ -799,7 +799,7 @@ mod tests {
         let n = make_rand_name();
         let s = repeat("x").take(10000).collect::<String>();
         set_var(&n, &s);
-        eq(var_os(&n), Some(s.as_slice()));
+        eq(var_os(&n), Some(&s));
         remove_var(&n);
         eq(var_os(&n), None);
     }

src/libstd/fs/mod.rs

@@ -828,7 +828,7 @@ mod tests {
     macro_rules! error { ($e:expr, $s:expr) => (
         match $e {
             Ok(_) => panic!("Unexpected success. Should've been: {:?}", $s),
-            Err(ref err) => assert!(err.to_string().contains($s.as_slice()),
+            Err(ref err) => assert!(err.to_string().contains($s),
                                     format!("`{}` did not contain `{}`", err, $s))
         }
     ) }
@@ -880,7 +880,7 @@ mod tests {
                 -1|0 => panic!("shouldn't happen"),
                 n => str::from_utf8(&read_buf[..n]).unwrap().to_string()
             };
-            assert_eq!(read_str.as_slice(), message);
+            assert_eq!(read_str, message);
         }
         check!(fs::remove_file(filename));
     }
@@ -1107,7 +1107,7 @@ mod tests {
                 check!(check!(File::open(&f)).read(&mut mem));
                 let read_str = str::from_utf8(&mem).unwrap();
                 let expected = format!("{}{}", prefix, n.to_str().unwrap());
-                assert_eq!(expected.as_slice(), read_str);
+                assert_eq!(expected, read_str);
             }
             check!(fs::remove_file(&f));
         }

src/libstd/process.rs

@@ -812,7 +812,7 @@ mod tests {
         for (ref k, ref v) in env::vars() {
             // don't check windows magical empty-named variables
             assert!(k.is_empty() ||
-                    output.contains(format!("{}={}", *k, *v).as_slice()),
+                    output.contains(&format!("{}={}", *k, *v)),
                     "output doesn't contain `{}={}`\n{}",
                     k, v, output);
         }
@@ -830,12 +830,12 @@ mod tests {
         for &(ref k, ref v) in &r {
             // don't check android RANDOM variables
             if *k != "RANDOM".to_string() {
-                assert!(output.contains(format!("{}={}",
-                                                *k,
-                                                *v).as_slice()) ||
-                        output.contains(format!("{}=\'{}\'",
-                                                *k,
-                                                *v).as_slice()));
+                assert!(output.contains(&format!("{}={}",
+                                                 *k,
+                                                 *v)) ||
+                        output.contains(&format!("{}=\'{}\'",
+                                                 *k,
+                                                 *v)));
             }
         }
     }

src/libstd/thread.rs

@@ -284,7 +284,7 @@ impl Builder {
                 stack::record_os_managed_stack_bounds(my_stack_bottom, my_stack_top);
             }
             match their_thread.name() {
-                Some(name) => unsafe { imp::set_name(name.as_slice()); },
+                Some(name) => unsafe { imp::set_name(name); },
                 None => {}
             }
             thread_info::set(

src/libsyntax/feature_gate.rs

@@ -403,11 +403,11 @@ impl<'a> Context<'a> {
                                for the compiler");
         } else {
             self.gate_feature("custom_attribute", attr.span,
-                       format!("The attribute `{}` is currently \
+                       &format!("The attribute `{}` is currently \
                                 unknown to the the compiler and \
                                 may have meaning \
                                 added to it in the future",
-                                name).as_slice());
+                                name));
         }
     }
 }

src/test/run-make/unicode-input/span_length.rs

@@ -80,7 +80,7 @@ fn main() {
                          .arg(format!("{} {}",
                                       rustc,
                                       main_file.as_str()
-                                               .unwrap()).as_slice())
+                                               .unwrap()))
                          .output().unwrap();
 
     let err = String::from_utf8_lossy(result.error.as_slice());