update everything to use Entry defaults

Author: Gankra

src/libcollections/btree/map.rs

@@ -1587,21 +1587,12 @@ impl<K: Ord, V> BTreeMap<K, V> {
     /// ```
     /// # #![feature(collections)]
     /// use std::collections::BTreeMap;
-    /// use std::collections::btree_map::Entry;
     ///
     /// let mut count: BTreeMap<&str, usize> = BTreeMap::new();
     ///
     /// // count the number of occurrences of letters in the vec
-    /// for x in vec!["a","b","a","c","a","b"].iter() {
-    ///     match count.entry(*x) {
-    ///         Entry::Vacant(view) => {
-    ///             view.insert(1);
-    ///         },
-    ///         Entry::Occupied(mut view) => {
-    ///             let v = view.get_mut();
-    ///             *v += 1;
-    ///         },
-    ///     }
+    /// for x in vec!["a","b","a","c","a","b"] {
+    ///     *count.entry(x).default(0) += 1;
     /// }
     ///
     /// assert_eq!(count["a"], 3);

src/libcollections/vec_map.rs

@@ -632,21 +632,12 @@ impl<V> VecMap<V> {
     /// ```
     /// # #![feature(collections)]
     /// use std::collections::VecMap;
-    /// use std::collections::vec_map::Entry;
     ///
     /// let mut count: VecMap<u32> = VecMap::new();
     ///
     /// // count the number of occurrences of numbers in the vec
-    /// for x in vec![1, 2, 1, 2, 3, 4, 1, 2, 4].iter() {
-    ///     match count.entry(*x) {
-    ///         Entry::Vacant(view) => {
-    ///             view.insert(1);
-    ///         },
-    ///         Entry::Occupied(mut view) => {
-    ///             let v = view.get_mut();
-    ///             *v += 1;
-    ///         },
-    ///     }
+    /// for x in vec![1, 2, 1, 2, 3, 4, 1, 2, 4] {
+    ///     *count.entry(x).default(0) += 1;
     /// }
     ///
     /// assert_eq!(count[1], 3);

src/librustc/metadata/loader.rs

@@ -426,8 +426,7 @@ impl<'a> Context<'a> {
             info!("lib candidate: {}", path.display());
 
             let hash_str = hash.to_string();
-            let slot = candidates.entry(hash_str).get().unwrap_or_else(
-                |vacant_entry| vacant_entry.insert((HashMap::new(), HashMap::new())));
+            let slot = candidates.entry(hash_str).default_with(|| (HashMap::new(), HashMap::new()));
             let (ref mut rlibs, ref mut dylibs) = *slot;
             if rlib {
                 rlibs.insert(fs::realpath(path).unwrap(), kind);

src/librustc/middle/dataflow.rs

@@ -160,12 +160,7 @@ fn build_nodeid_to_index(decl: Option<&ast::FnDecl>,
 
     cfg.graph.each_node(|node_idx, node| {
         if let cfg::CFGNodeData::AST(id) = node.data {
-            match index.entry(id).get() {
-                Ok(v) => v.push(node_idx),
-                Err(e) => {
-                    e.insert(vec![node_idx]);
-                }
-            }
+            index.entry(id).default(vec![]).push(node_idx);
         }
         true
     });
@@ -185,12 +180,7 @@ fn build_nodeid_to_index(decl: Option<&ast::FnDecl>,
         visit::walk_fn_decl(&mut formals, decl);
         impl<'a, 'v> visit::Visitor<'v> for Formals<'a> {
             fn visit_pat(&mut self, p: &ast::Pat) {
-                match self.index.entry(p.id).get() {
-                    Ok(v) => v.push(self.entry),
-                    Err(e) => {
-                        e.insert(vec![self.entry]);
-                    }
-                }
+                self.index.entry(p.id).default(vec![]).push(self.entry);
                 visit::walk_pat(self, p)
             }
         }

src/librustc/middle/traits/fulfill.rs

@@ -11,7 +11,6 @@
 use middle::infer::{InferCtxt};
 use middle::ty::{self, RegionEscape, Ty};
 use std::collections::HashSet;
-use std::collections::hash_map::Entry::{Occupied, Vacant};
 use std::default::Default;
 use syntax::ast;
 use util::common::ErrorReported;
@@ -437,9 +436,7 @@ fn register_region_obligation<'tcx>(tcx: &ty::ctxt<'tcx>,
     debug!("register_region_obligation({})",
            region_obligation.repr(tcx));
 
-    match region_obligations.entry(region_obligation.cause.body_id) {
-        Vacant(entry) => { entry.insert(vec![region_obligation]); },
-        Occupied(mut entry) => { entry.get_mut().push(region_obligation); },
-    }
+    region_obligations.entry(region_obligation.cause.body_id).default(vec![])
+        .push(region_obligation);
 
 }

src/librustc/middle/ty.rs

@@ -5669,9 +5669,7 @@ pub fn lookup_field_type<'tcx>(tcx: &ctxt<'tcx>,
         node_id_to_type(tcx, id.node)
     } else {
         let mut tcache = tcx.tcache.borrow_mut();
-        let pty = tcache.entry(id).get().unwrap_or_else(
-            |vacant_entry| vacant_entry.insert(csearch::get_field_type(tcx, struct_id, id)));
-        pty.ty
+        tcache.entry(id).default_with(|| csearch::get_field_type(tcx, struct_id, id)).ty
     };
     ty.subst(tcx, substs)
 }
@@ -6819,9 +6817,7 @@ pub fn replace_late_bound_regions<'tcx, T, F>(
         debug!("region={}", region.repr(tcx));
         match region {
             ty::ReLateBound(debruijn, br) if debruijn.depth == current_depth => {
-                let region =
-                    * map.entry(br).get().unwrap_or_else(
-                        |vacant_entry| vacant_entry.insert(mapf(br)));
+                let region = *map.entry(br).default_with(|| mapf(br));
 
                 if let ty::ReLateBound(debruijn1, br) = region {
                     // If the callback returns a late-bound region,

src/librustc/session/config.rs

@@ -35,7 +35,6 @@ use syntax::parse::token::InternedString;
 
 use getopts;
 use std::collections::HashMap;
-use std::collections::hash_map::Entry::{Occupied, Vacant};
 use std::env;
 use std::fmt;
 use std::path::PathBuf;
@@ -1037,10 +1036,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
             None => early_error("--extern value must be of the format `foo=bar`"),
         };
 
-        match externs.entry(name.to_string()) {
-            Vacant(entry) => { entry.insert(vec![location.to_string()]); },
-            Occupied(mut entry) => { entry.get_mut().push(location.to_string()); },
-        }
+        externs.entry(name.to_string()).default(vec![]).push(location.to_string());
     }
 
     let crate_name = matches.opt_str("crate-name");

src/librustc_typeck/check/mod.rs

@@ -112,7 +112,6 @@ use util::nodemap::{DefIdMap, FnvHashMap, NodeMap};
 use util::lev_distance::lev_distance;
 
 use std::cell::{Cell, Ref, RefCell};
-use std::collections::hash_map::Entry::{Occupied, Vacant};
 use std::mem::replace;
 use std::rc::Rc;
 use std::iter::repeat;
@@ -1362,11 +1361,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                        closure_def_id: ast::DefId,
                                        r: DeferredCallResolutionHandler<'tcx>) {
         let mut deferred_call_resolutions = self.inh.deferred_call_resolutions.borrow_mut();
-        let mut vec = match deferred_call_resolutions.entry(closure_def_id) {
-            Occupied(entry) => entry.into_mut(),
-            Vacant(entry) => entry.insert(Vec::new()),
-        };
-        vec.push(r);
+        deferred_call_resolutions.entry(closure_def_id).default(vec![]).push(r);
     }
 
     fn remove_deferred_call_resolutions(&self,

src/librustdoc/html/render.rs

@@ -876,9 +876,7 @@ impl DocFolder for Cache {
         if let clean::ImplItem(ref i) = item.inner {
             match i.trait_ {
                 Some(clean::ResolvedPath{ did, .. }) => {
-                    let v = self.implementors.entry(did).get().unwrap_or_else(
-                        |vacant_entry| vacant_entry.insert(Vec::with_capacity(1)));
-                    v.push(Implementor {
+                    self.implementors.entry(did).default(vec![]).push(Implementor {
                         def_id: item.def_id,
                         generics: i.generics.clone(),
                         trait_: i.trait_.as_ref().unwrap().clone(),
@@ -1080,9 +1078,7 @@ impl DocFolder for Cache {
                         };
 
                         if let Some(did) = did {
-                            let v = self.impls.entry(did).get().unwrap_or_else(
-                                |vacant_entry| vacant_entry.insert(Vec::with_capacity(1)));
-                            v.push(Impl {
+                            self.impls.entry(did).default(vec![]).push(Impl {
                                 impl_: i,
                                 dox: dox,
                                 stability: item.stability.clone(),
@@ -1334,9 +1330,8 @@ impl Context {
                 Some(ref s) => s.to_string(),
             };
             let short = short.to_string();
-            let v = map.entry(short).get().unwrap_or_else(
-                |vacant_entry| vacant_entry.insert(Vec::with_capacity(1)));
-            v.push((myname, Some(plain_summary_line(item.doc_value()))));
+            map.entry(short).default(vec![])
+                .push((myname, Some(plain_summary_line(item.doc_value()))));
         }
 
         for (_, items) in &mut map {

src/librustdoc/lib.rs

@@ -352,9 +352,7 @@ fn parse_externs(matches: &getopts::Matches) -> Result<core::Externs, String> {
             }
         };
         let name = name.to_string();
-        let locs = externs.entry(name).get().unwrap_or_else(
-            |vacant_entry| vacant_entry.insert(Vec::with_capacity(1)));
-        locs.push(location.to_string());
+        externs.entry(name).default(vec![]).push(location.to_string());
     }
     Ok(externs)
 }