auto merge of #18914 : Gankro/rust/cloned, r=aturon

Part of #18424. r? @aturon 

[breaking-change]

Author: bors

src/libcore/option.rs

@@ -150,6 +150,7 @@ use mem;
 use result::{Result, Ok, Err};
 use slice;
 use slice::AsSlice;
+use clone::Clone;
 
 // Note that this is not a lang item per se, but it has a hidden dependency on
 // `Iterator`, which is one. The compiler assumes that the `next` method of
@@ -691,6 +692,14 @@ impl<T> Option<T> {
     }
 }
 
+impl<'a, T: Clone> Option<&'a T> {
+    /// Maps an Option<&T> to an Option<T> by cloning the contents of the Option<&T>.
+    #[unstable = "recently added as part of collections reform"]
+    pub fn cloned(self) -> Option<T> {
+        self.map(|t| t.clone())
+    }
+}
+
 impl<T: Default> Option<T> {
     /// Returns the contained value or a default
     ///

src/libcoretest/option.rs

@@ -11,6 +11,7 @@
 use core::option::*;
 use core::kinds::marker;
 use core::mem;
+use core::clone::Clone;
 
 #[test]
 fn test_get_ptr() {
@@ -239,3 +240,15 @@ fn test_collect() {
 
     assert!(v == None);
 }
+
+fn test_cloned() {
+    let s = 1u32;
+    let n: Option<&'static u32> = None;
+    let o = Some(&s);
+
+    assert_eq!(o.clone(), Some(&s));
+    assert_eq!(o.cloned(), Some(1u32));
+
+    assert_eq!(n.clone(), None);
+    assert_eq!(n.cloned(), None);
+}

src/librustc/lint/builtin.rs

@@ -391,7 +391,7 @@ struct ImproperCTypesVisitor<'a, 'tcx: 'a> {
 
 impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
     fn check_def(&mut self, sp: Span, ty_id: ast::NodeId, path_id: ast::NodeId) {
-        match self.cx.tcx.def_map.borrow().get_copy(&path_id) {
+        match self.cx.tcx.def_map.borrow()[path_id].clone() {
             def::DefPrimTy(ast::TyInt(ast::TyI)) => {
                 self.cx.span_lint(IMPROPER_CTYPES, sp,
                                   "found rust type `int` in foreign module, while \
@@ -869,7 +869,7 @@ fn method_context(cx: &Context, m: &ast::Method) -> MethodContext {
         node: m.id
     };
 
-    match cx.tcx.impl_or_trait_items.borrow().find_copy(&did) {
+    match cx.tcx.impl_or_trait_items.borrow().get(&did).cloned() {
         None => cx.sess().span_bug(m.span, "missing method descriptor?!"),
         Some(md) => {
             match md {

src/librustc/metadata/encoder.rs

@@ -1863,7 +1863,7 @@ impl<'a, 'b, 'c, 'tcx, 'v> Visitor<'v> for ImplVisitor<'a, 'b, 'c, 'tcx> {
         match item.node {
             ItemImpl(_, Some(ref trait_ref), _, _) => {
                 let def_map = &self.ecx.tcx.def_map;
-                let trait_def = def_map.borrow().get_copy(&trait_ref.ref_id);
+                let trait_def = def_map.borrow()[trait_ref.ref_id].clone();
                 let def_id = trait_def.def_id();
 
                 // Load eagerly if this is an implementation of the Drop trait

src/librustc/metadata/tydecode.rs

@@ -439,7 +439,7 @@ fn parse_ty(st: &mut PState, conv: conv_did) -> ty::t {
                                          pos: pos,
                                          len: len };
 
-        match st.tcx.rcache.borrow().find_copy(&key) {
+        match st.tcx.rcache.borrow().get(&key).cloned() {
           Some(tt) => return tt,
           None => {}
         }

src/librustc/middle/astencode.rs

@@ -1200,8 +1200,7 @@ fn encode_side_tables_for_id(ecx: &e::EncodeContext,
                                 var_id: var_id,
                                 closure_expr_id: id
                             };
-                            let upvar_borrow = tcx.upvar_borrow_map.borrow()
-                                                  .get_copy(&upvar_id);
+                            let upvar_borrow = tcx.upvar_borrow_map.borrow()[upvar_id].clone();
                             var_id.encode(rbml_w);
                             upvar_borrow.encode(rbml_w);
                         })

src/librustc/middle/borrowck/move_data.rs

@@ -295,7 +295,7 @@ impl MoveData {
 
     fn existing_move_path(&self, lp: &Rc<LoanPath>)
                           -> Option<MovePathIndex> {
-        self.path_map.borrow().find_copy(lp)
+        self.path_map.borrow().get(lp).cloned()
     }
 
     fn existing_base_paths(&self, lp: &Rc<LoanPath>)
@@ -312,7 +312,7 @@ impl MoveData {
          * paths of `lp` to `result`, but does not add new move paths
          */
 
-        match self.path_map.borrow().find_copy(lp) {
+        match self.path_map.borrow().get(lp).cloned() {
             Some(index) => {
                 self.each_base_path(index, |p| {
                     result.push(p);

src/librustc/middle/check_match.rs

@@ -359,7 +359,7 @@ impl<'a, 'tcx> Folder for StaticInliner<'a, 'tcx> {
     fn fold_pat(&mut self, pat: P<Pat>) -> P<Pat> {
         match pat.node {
             PatIdent(..) | PatEnum(..) => {
-                let def = self.tcx.def_map.borrow().find_copy(&pat.id);
+                let def = self.tcx.def_map.borrow().get(&pat.id).cloned();
                 match def {
                     Some(DefConst(did)) => match lookup_const_by_id(self.tcx, did) {
                         Some(const_expr) => {
@@ -749,7 +749,7 @@ pub fn specialize<'a>(cx: &MatchCheckCtxt, r: &[&'a Pat],
             Some(Vec::from_elem(arity, DUMMY_WILD_PAT)),
 
         &PatIdent(_, _, _) => {
-            let opt_def = cx.tcx.def_map.borrow().find_copy(&pat_id);
+            let opt_def = cx.tcx.def_map.borrow().get(&pat_id).cloned();
             match opt_def {
                 Some(DefConst(..)) =>
                     cx.tcx.sess.span_bug(pat_span, "const pattern should've \
@@ -764,7 +764,7 @@ pub fn specialize<'a>(cx: &MatchCheckCtxt, r: &[&'a Pat],
         }
 
         &PatEnum(_, ref args) => {
-            let def = cx.tcx.def_map.borrow().get_copy(&pat_id);
+            let def = cx.tcx.def_map.borrow()[pat_id].clone();
             match def {
                 DefConst(..) =>
                     cx.tcx.sess.span_bug(pat_span, "const pattern should've \
@@ -782,7 +782,7 @@ pub fn specialize<'a>(cx: &MatchCheckCtxt, r: &[&'a Pat],
 
         &PatStruct(_, ref pattern_fields, _) => {
             // Is this a struct or an enum variant?
-            let def = cx.tcx.def_map.borrow().get_copy(&pat_id);
+            let def = cx.tcx.def_map.borrow()[pat_id].clone();
             let class_id = match def {
                 DefConst(..) =>
                     cx.tcx.sess.span_bug(pat_span, "const pattern should've \

src/librustc/middle/const_eval.rs

@@ -85,7 +85,7 @@ pub fn join_all<It: Iterator<constness>>(mut cs: It) -> constness {
 }
 
 fn lookup_const<'a>(tcx: &'a ty::ctxt, e: &Expr) -> Option<&'a Expr> {
-    let opt_def = tcx.def_map.borrow().find_copy(&e.id);
+    let opt_def = tcx.def_map.borrow().get(&e.id).cloned();
     match opt_def {
         Some(def::DefConst(def_id)) => {
             lookup_const_by_id(tcx, def_id)
@@ -320,7 +320,7 @@ pub fn const_expr_to_pat(tcx: &ty::ctxt, expr: &Expr) -> P<Pat> {
             PatTup(exprs.iter().map(|expr| const_expr_to_pat(tcx, &**expr)).collect()),
 
         ExprCall(ref callee, ref args) => {
-            let def = tcx.def_map.borrow().get_copy(&callee.id);
+            let def = tcx.def_map.borrow()[callee.id].clone();
             match tcx.def_map.borrow_mut().entry(expr.id) {
               Vacant(entry) => { entry.set(def); }
               _ => {}
@@ -352,7 +352,7 @@ pub fn const_expr_to_pat(tcx: &ty::ctxt, expr: &Expr) -> P<Pat> {
         }
 
         ExprPath(ref path) => {
-            let opt_def = tcx.def_map.borrow().find_copy(&expr.id);
+            let opt_def = tcx.def_map.borrow().get(&expr.id).cloned();
             match opt_def {
                 Some(def::DefStruct(..)) =>
                     PatStruct(path.clone(), vec![], false),

src/librustc/middle/expr_use_visitor.rs

@@ -850,7 +850,7 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,TYPER> {
 
                 // Each match binding is effectively an assignment to the
                 // binding being produced.
-                let def = def_map.borrow().get_copy(&pat.id);
+                let def = def_map.borrow()[pat.id].clone();
                 match mc.cat_def(pat.id, pat.span, pat_ty, def) {
                     Ok(binding_cmt) => {
                         delegate.mutate(pat.id, pat.span, binding_cmt, Init);
@@ -957,8 +957,7 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,TYPER> {
             // inferred by regionbk
             let upvar_id = ty::UpvarId { var_id: id_var,
                                          closure_expr_id: closure_expr.id };
-            let upvar_borrow = self.tcx().upvar_borrow_map.borrow()
-                                   .get_copy(&upvar_id);
+            let upvar_borrow = self.tcx().upvar_borrow_map.borrow()[upvar_id].clone();
 
             self.delegate.borrow(closure_expr.id,
                                  closure_expr.span,