auto merge of #8294 : erickt/rust/map-move, r=bblum

According to #7887, we've decided to use the syntax of `fn map<U>(f: &fn(&T) -> U) -> U`, which passes a reference to the closure, and to `fn map_move<U>(f: &fn(T) -> U) -> U` which moves the value into the closure. This PR adds these `.map_move()` functions to `Option` and `Result`.

In addition, it has these other minor features:
 
* Replaces a couple uses of `option.get()`, `result.get()`, and `result.get_err()` with `option.unwrap()`, `result.unwrap()`, and `result.unwrap_err()`. (See #8268 and #8288 for a more thorough adaptation of this functionality.
* Removes `option.take_map()` and `option.take_map_default()`. These two functions can be easily written as `.take().map_move(...)`.
* Adds a better error message to `result.unwrap()` and `result.unwrap_err()`.

Author: bors

src/compiletest/compiletest.rs

@@ -109,8 +109,8 @@ pub fn parse_config(args: ~[~str]) -> config {
         compile_lib_path: getopts::opt_str(matches, "compile-lib-path"),
         run_lib_path: getopts::opt_str(matches, "run-lib-path"),
         rustc_path: opt_path(matches, "rustc-path"),
-        clang_path: getopts::opt_maybe_str(matches, "clang-path").map(|s| Path(*s)),
-        llvm_bin_path: getopts::opt_maybe_str(matches, "llvm-bin-path").map(|s| Path(*s)),
+        clang_path: getopts::opt_maybe_str(matches, "clang-path").map_move(|s| Path(s)),
+        llvm_bin_path: getopts::opt_maybe_str(matches, "llvm-bin-path").map_move(|s| Path(s)),
         src_base: opt_path(matches, "src-base"),
         build_base: opt_path(matches, "build-base"),
         aux_base: opt_path(matches, "aux-base"),
@@ -123,14 +123,14 @@ pub fn parse_config(args: ~[~str]) -> config {
             } else {
                 None
             },
-        logfile: getopts::opt_maybe_str(matches, "logfile").map(|s| Path(*s)),
-        save_metrics: getopts::opt_maybe_str(matches, "save-metrics").map(|s| Path(*s)),
+        logfile: getopts::opt_maybe_str(matches, "logfile").map_move(|s| Path(s)),
+        save_metrics: getopts::opt_maybe_str(matches, "save-metrics").map_move(|s| Path(s)),
         ratchet_metrics:
-            getopts::opt_maybe_str(matches, "ratchet-metrics").map(|s| Path(*s)),
+            getopts::opt_maybe_str(matches, "ratchet-metrics").map_move(|s| Path(s)),
         ratchet_noise_percent:
             getopts::opt_maybe_str(matches,
-                                   "ratchet-noise-percent").map(|s|
-                                                                f64::from_str(*s).unwrap()),
+                                   "ratchet-noise-percent").map_move(|s|
+                                                                     f64::from_str(s).unwrap()),
         runtool: getopts::opt_maybe_str(matches, "runtool"),
         rustcflags: getopts::opt_maybe_str(matches, "rustcflags"),
         jit: getopts::opt_present(matches, "jit"),

src/compiletest/runtest.rs

@@ -162,9 +162,8 @@ fn run_pretty_test(config: &config, props: &TestProps, testfile: &Path) {
         round += 1;
     }
 
-    let mut expected =
-        match props.pp_exact {
-          Some(ref file) => {
+    let mut expected = match props.pp_exact {
+        Some(ref file) => {
             let filepath = testfile.dir_path().push_rel(file);
             io::read_whole_file_str(&filepath).unwrap()
           }

src/libextra/dlist.rs

@@ -164,7 +164,7 @@ impl<T> DList<T> {
     /// Remove the first Node and return it, or None if the list is empty
     #[inline]
     fn pop_front_node(&mut self) -> Option<~Node<T>> {
-        do self.list_head.take().map_consume |mut front_node| {
+        do self.list_head.take().map_move |mut front_node| {
             self.length -= 1;
             match front_node.next.take() {
                 Some(node) => self.list_head = link_with_prev(node, Rawlink::none()),
@@ -190,7 +190,7 @@ impl<T> DList<T> {
     /// Remove the last Node and return it, or None if the list is empty
     #[inline]
     fn pop_back_node(&mut self) -> Option<~Node<T>> {
-        do self.list_tail.resolve().map_consume_default(None) |tail| {
+        do self.list_tail.resolve().map_move_default(None) |tail| {
             self.length -= 1;
             self.list_tail = tail.prev;
             match tail.prev.resolve() {
@@ -237,7 +237,7 @@ impl<T> Deque<T> for DList<T> {
     ///
     /// O(1)
     fn pop_front(&mut self) -> Option<T> {
-        self.pop_front_node().map_consume(|~Node{value, _}| value)
+        self.pop_front_node().map_move(|~Node{value, _}| value)
     }
 
     /// Add an element last in the list
@@ -251,7 +251,7 @@ impl<T> Deque<T> for DList<T> {
     ///
     /// O(1)
     fn pop_back(&mut self) -> Option<T> {
-        self.pop_back_node().map_consume(|~Node{value, _}| value)
+        self.pop_back_node().map_move(|~Node{value, _}| value)
     }
 }
 
@@ -267,7 +267,7 @@ impl<T> DList<T> {
     /// If the list is empty, do nothing.
     #[inline]
     pub fn rotate_forward(&mut self) {
-        do self.pop_back_node().map_consume |tail| {
+        do self.pop_back_node().map_move |tail| {
             self.push_front_node(tail)
         };
     }
@@ -277,7 +277,7 @@ impl<T> DList<T> {
     /// If the list is empty, do nothing.
     #[inline]
     pub fn rotate_backward(&mut self) {
-        do self.pop_front_node().map_consume |head| {
+        do self.pop_front_node().map_move |head| {
             self.push_back_node(head)
         };
     }
@@ -463,7 +463,7 @@ impl<'self, A> DoubleEndedIterator<&'self A> for DListIterator<'self, A> {
         if self.nelem == 0 {
             return None;
         }
-        do self.tail.resolve().map_consume |prev| {
+        do self.tail.resolve().map_move |prev| {
             self.nelem -= 1;
             self.tail = prev.prev;
             &prev.value
@@ -477,7 +477,7 @@ impl<'self, A> Iterator<&'self mut A> for MutDListIterator<'self, A> {
         if self.nelem == 0 {
             return None;
         }
-        do self.head.resolve().map_consume |next| {
+        do self.head.resolve().map_move |next| {
             self.nelem -= 1;
             self.head = match next.next {
                 Some(ref mut node) => Rawlink::some(&mut **node),
@@ -499,7 +499,7 @@ impl<'self, A> DoubleEndedIterator<&'self mut A> for MutDListIterator<'self, A>
         if self.nelem == 0 {
             return None;
         }
-        do self.tail.resolve().map_consume |prev| {
+        do self.tail.resolve().map_move |prev| {
             self.nelem -= 1;
             self.tail = prev.prev;
             &mut prev.value
@@ -553,7 +553,7 @@ impl<'self, A> ListInsertion<A> for MutDListIterator<'self, A> {
         if self.nelem == 0 {
             return None
         }
-        self.head.resolve().map_consume(|head| &mut head.value)
+        self.head.resolve().map_move(|head| &mut head.value)
     }
 }
 

src/libextra/num/bigint.rs

@@ -548,7 +548,7 @@ impl BigUint {
 
     pub fn new(v: ~[BigDigit]) -> BigUint {
         // omit trailing zeros
-        let new_len = v.rposition(|n| *n != 0).map_default(0, |p| *p + 1);
+        let new_len = v.rposition(|n| *n != 0).map_move_default(0, |p| p + 1);
 
         if new_len == v.len() { return BigUint { data: v }; }
         let mut v = v;
@@ -1145,7 +1145,7 @@ impl BigInt {
             start = 1;
         }
         return BigUint::parse_bytes(buf.slice(start, buf.len()), radix)
-            .map_consume(|bu| BigInt::from_biguint(sign, bu));
+            .map_move(|bu| BigInt::from_biguint(sign, bu));
     }
 
     pub fn to_uint(&self) -> uint {
@@ -2028,7 +2028,7 @@ mod bigint_tests {
     #[test]
     fn test_from_str_radix() {
         fn check(s: &str, ans: Option<int>) {
-            let ans = ans.map(|&n| IntConvertible::from_int::<BigInt>(n));
+            let ans = ans.map_move(|n| IntConvertible::from_int::<BigInt>(n));
             assert_eq!(FromStrRadix::from_str_radix(s, 10), ans);
         }
         check("10", Some(10));

src/libextra/smallintmap.rs

@@ -203,7 +203,7 @@ impl<V> SmallIntMap<V> {
     {
         let values = replace(&mut self.v, ~[]);
         values.consume_iter().enumerate().filter_map(|(i, v)| {
-            v.map_consume(|v| (i, v))
+            v.map_move(|v| (i, v))
         })
     }
 }

src/libextra/term.rs

@@ -127,7 +127,7 @@ impl Terminal {
         let inf = ti.unwrap();
         let nc = if inf.strings.find_equiv(&("setaf")).is_some()
                  && inf.strings.find_equiv(&("setab")).is_some() {
-                     inf.numbers.find_equiv(&("colors")).map_consume_default(0, |&n| n)
+                     inf.numbers.find_equiv(&("colors")).map_move_default(0, |&n| n)
                  } else { 0 };
 
         return Ok(Terminal {out: out, ti: inf, num_colors: nc});
@@ -220,7 +220,7 @@ impl Terminal {
                 cap = self.ti.strings.find_equiv(&("op"));
             }
         }
-        let s = do cap.map_consume_default(Err(~"can't find terminfo capability `sgr0`")) |op| {
+        let s = do cap.map_move_default(Err(~"can't find terminfo capability `sgr0`")) |op| {
             expand(*op, [], &mut Variables::new())
         };
         if s.is_ok() {

src/libextra/test.rs

@@ -238,20 +238,20 @@ pub fn parse_opts(args: &[~str]) -> OptRes {
     let run_ignored = getopts::opt_present(&matches, "ignored");
 
     let logfile = getopts::opt_maybe_str(&matches, "logfile");
-    let logfile = logfile.map(|s| Path(*s));
+    let logfile = logfile.map_move(|s| Path(s));
 
     let run_benchmarks = getopts::opt_present(&matches, "bench");
     let run_tests = ! run_benchmarks ||
         getopts::opt_present(&matches, "test");
 
     let ratchet_metrics = getopts::opt_maybe_str(&matches, "ratchet-metrics");
-    let ratchet_metrics = ratchet_metrics.map(|s| Path(*s));
+    let ratchet_metrics = ratchet_metrics.map_move(|s| Path(s));
 
     let ratchet_noise_percent = getopts::opt_maybe_str(&matches, "ratchet-noise-percent");
-    let ratchet_noise_percent = ratchet_noise_percent.map(|s| f64::from_str(*s).unwrap());
+    let ratchet_noise_percent = ratchet_noise_percent.map_move(|s| f64::from_str(s).unwrap());
 
     let save_metrics = getopts::opt_maybe_str(&matches, "save-metrics");
-    let save_metrics = save_metrics.map(|s| Path(*s));
+    let save_metrics = save_metrics.map_move(|s| Path(s));
 
     let test_opts = TestOpts {
         filter: filter,

src/libextra/treemap.rs

@@ -394,7 +394,7 @@ impl<'self, T> Iterator<&'self T> for TreeSetIterator<'self, T> {
     /// Advance the iterator to the next node (in order). If there are no more nodes, return `None`.
     #[inline]
     fn next(&mut self) -> Option<&'self T> {
-        do self.iter.next().map |&(value, _)| { value }
+        do self.iter.next().map_move |(value, _)| { value }
     }
 }
 

src/libextra/workcache.rs

@@ -221,7 +221,7 @@ fn digest<T:Encodable<json::Encoder>>(t: &T) -> ~str {
 fn digest_file(path: &Path) -> ~str {
     let mut sha = ~Sha1::new();
     let s = io::read_whole_file_str(path);
-    (*sha).input_str(*s.get_ref());
+    (*sha).input_str(s.unwrap());
     (*sha).result_str()
 }
 
@@ -378,7 +378,7 @@ fn test() {
     let pth = Path("foo.c");
     {
         let r = io::file_writer(&pth, [io::Create]);
-        r.get_ref().write_str("int main() { return 0; }");
+        r.unwrap().write_str("int main() { return 0; }");
     }
 
     let cx = Context::new(RWArc::new(Database::new(Path("db.json"))),

src/librust/rust.rs

@@ -130,7 +130,7 @@ fn rustc_help() {
 fn find_cmd(command_string: &str) -> Option<Command> {
     do COMMANDS.iter().find_ |command| {
         command.cmd == command_string
-    }.map_consume(|x| *x)
+    }.map_move(|x| *x)
 }
 
 fn cmd_help(args: &[~str]) -> ValidUsage {

src/librustc/driver/driver.rs

@@ -669,8 +669,7 @@ pub fn build_session_options(binary: @str,
         } else if opt_present(matches, "emit-llvm") {
             link::output_type_bitcode
         } else { link::output_type_exe };
-    let sysroot_opt = getopts::opt_maybe_str(matches, "sysroot");
-    let sysroot_opt = sysroot_opt.map(|m| @Path(*m));
+    let sysroot_opt = getopts::opt_maybe_str(matches, "sysroot").map_move(|m| @Path(m));
     let target_opt = getopts::opt_maybe_str(matches, "target");
     let target_feature_opt = getopts::opt_maybe_str(matches, "target-feature");
     let save_temps = getopts::opt_present(matches, "save-temps");

src/librustc/front/config.rs

@@ -61,7 +61,9 @@ fn fold_mod(cx: @Context, m: &ast::_mod, fld: @fold::ast_fold) -> ast::_mod {
         filter_item(cx, *a).chain(|x| fld.fold_item(x))
     }.collect();
     let filtered_view_items = do m.view_items.iter().filter_map |a| {
-        filter_view_item(cx, a).map(|&x| fld.fold_view_item(x))
+        do filter_view_item(cx, a).map_move |x| {
+            fld.fold_view_item(x)
+        }
     }.collect();
     ast::_mod {
         view_items: filtered_view_items,
@@ -83,7 +85,9 @@ fn fold_foreign_mod(
 ) -> ast::foreign_mod {
     let filtered_items = nm.items.iter().filter_map(|a| filter_foreign_item(cx, *a)).collect();
     let filtered_view_items = do nm.view_items.iter().filter_map |a| {
-        filter_view_item(cx, a).map(|&x| fld.fold_view_item(x))
+        do filter_view_item(cx, a).map_move |x| {
+            fld.fold_view_item(x)
+        }
     }.collect();
     ast::foreign_mod {
         sort: nm.sort,
@@ -138,7 +142,7 @@ fn fold_block(
         filter_stmt(cx, *a).chain(|stmt| fld.fold_stmt(stmt))
     }.collect();
     let filtered_view_items = do b.view_items.iter().filter_map |a| {
-        filter_view_item(cx, a).map(|&x| fld.fold_view_item(x))
+        filter_view_item(cx, a).map(|x| fld.fold_view_item(*x))
     }.collect();
     ast::Block {
         view_items: filtered_view_items,

src/librustc/lib/llvm.rs

@@ -2159,7 +2159,7 @@ impl TypeNames {
     }
 
     pub fn find_type(&self, s: &str) -> Option<Type> {
-        self.named_types.find_equiv(&s).map_consume(|x| Type::from_ref(*x))
+        self.named_types.find_equiv(&s).map_move(|x| Type::from_ref(*x))
     }
 
     // We have a depth count, because we seem to make infinite types.

src/librustc/metadata/cstore.rs

@@ -133,7 +133,7 @@ pub fn add_extern_mod_stmt_cnum(cstore: &mut CStore,
 pub fn find_extern_mod_stmt_cnum(cstore: &CStore,
                                  emod_id: ast::NodeId)
                        -> Option<ast::CrateNum> {
-    cstore.extern_mod_crate_map.find(&emod_id).map_consume(|x| *x)
+    cstore.extern_mod_crate_map.find(&emod_id).map_move(|x| *x)
 }
 
 #[deriving(Clone)]

src/librustc/metadata/decoder.rs

@@ -198,8 +198,8 @@ fn item_def_id(d: ebml::Doc, cdata: cmd) -> ast::def_id {
 }
 
 fn get_provided_source(d: ebml::Doc, cdata: cmd) -> Option<ast::def_id> {
-    do reader::maybe_get_doc(d, tag_item_method_provided_source).map |doc| {
-        translate_def_id(cdata, reader::with_doc_data(*doc, parse_def_id))
+    do reader::maybe_get_doc(d, tag_item_method_provided_source).map_move |doc| {
+        translate_def_id(cdata, reader::with_doc_data(doc, parse_def_id))
     }
 }
 
@@ -265,10 +265,10 @@ fn item_ty_param_defs(item: ebml::Doc, tcx: ty::ctxt, cdata: cmd,
 }
 
 fn item_ty_region_param(item: ebml::Doc) -> Option<ty::region_variance> {
-    reader::maybe_get_doc(item, tag_region_param).map(|doc| {
-        let mut decoder = reader::Decoder(*doc);
+    do reader::maybe_get_doc(item, tag_region_param).map_move |doc| {
+        let mut decoder = reader::Decoder(doc);
         Decodable::decode(&mut decoder)
-    })
+    }
 }
 
 fn item_ty_param_count(item: ebml::Doc) -> uint {
@@ -415,7 +415,7 @@ pub fn get_impl_trait(cdata: cmd,
                        tcx: ty::ctxt) -> Option<@ty::TraitRef>
 {
     let item_doc = lookup_item(id, cdata.data);
-    do reader::maybe_get_doc(item_doc, tag_item_trait_ref).map |&tp| {
+    do reader::maybe_get_doc(item_doc, tag_item_trait_ref).map_move |tp| {
         @doc_trait_ref(tp, tcx, cdata)
     }
 }

src/librustc/middle/borrowck/mod.rs

@@ -286,13 +286,15 @@ pub fn opt_loan_path(cmt: mc::cmt) -> Option<@LoanPath> {
         }
 
         mc::cat_deref(cmt_base, _, _) => {
-            opt_loan_path(cmt_base).map(
-                |&lp| @LpExtend(lp, cmt.mutbl, LpDeref))
+            do opt_loan_path(cmt_base).map_move |lp| {
+                @LpExtend(lp, cmt.mutbl, LpDeref)
+            }
         }
 
         mc::cat_interior(cmt_base, ik) => {
-            opt_loan_path(cmt_base).map(
-                |&lp| @LpExtend(lp, cmt.mutbl, LpInterior(ik)))
+            do opt_loan_path(cmt_base).map_move |lp| {
+                @LpExtend(lp, cmt.mutbl, LpInterior(ik))
+            }
         }
 
         mc::cat_downcast(cmt_base) |

src/librustc/middle/const_eval.rs

@@ -493,9 +493,9 @@ pub fn compare_lit_exprs(tcx: middle::ty::ctxt, a: &expr, b: &expr) -> Option<in
 }
 
 pub fn lit_expr_eq(tcx: middle::ty::ctxt, a: &expr, b: &expr) -> Option<bool> {
-    compare_lit_exprs(tcx, a, b).map(|&val| val == 0)
+    compare_lit_exprs(tcx, a, b).map_move(|val| val == 0)
 }
 
 pub fn lit_eq(a: &lit, b: &lit) -> Option<bool> {
-    compare_const_vals(&lit_to_const(a), &lit_to_const(b)).map(|&val| val == 0)
+    compare_const_vals(&lit_to_const(a), &lit_to_const(b)).map_move(|val| val == 0)
 }

src/librustc/middle/lang_items.rs

@@ -393,7 +393,7 @@ impl<'self> LanguageItemCollector<'self> {
             return;    // Didn't match.
         }
 
-        let item_index = self.item_refs.find(&value).map(|x| **x);
+        let item_index = self.item_refs.find(&value).map_move(|x| *x);
         // prevent borrow checker from considering   ^~~~~~~~~~~
         // self to be borrowed (annoying)