auto merge of rust-lang#20160 : nick29581/rust/ranges2, r=nikomatsakis

The first six commits are from an earlier PR (rust-lang#19858) and have already been reviewed. This PR makes an awful hack in the compiler to accommodate slices both natively and in the index a range form. After a snapshot we can hopefully add the new Index impls and then we can remove these awful hacks.

r? @nikomatsakis (or anyone who knows the compiler, really)

Author: bors

src/libcollections/ring_buf.rs

@@ -453,7 +453,7 @@ impl<T> RingBuf<T> {
 
             if contiguous {
                 let (empty, buf) = buf.split_at_mut(0);
-                (buf[mut tail..head], empty)
+                (buf.slice_mut(tail, head), empty)
             } else {
                 let (mid, right) = buf.split_at_mut(tail);
                 let (left, _) = mid.split_at_mut(head);

src/libcollections/slice.rs

@@ -94,7 +94,7 @@ use core::iter::{range_step, MultiplicativeIterator};
 use core::kinds::Sized;
 use core::mem::size_of;
 use core::mem;
-use core::ops::FnMut;
+use core::ops::{FnMut,SliceMut};
 use core::prelude::{Clone, Greater, Iterator, IteratorExt, Less, None, Option};
 use core::prelude::{Ord, Ordering, RawPtr, Some, range};
 use core::ptr;
@@ -1110,7 +1110,7 @@ impl<T> SliceExt<T> for [T] {
 
     #[inline]
     fn move_from(&mut self, mut src: Vec<T>, start: uint, end: uint) -> uint {
-        for (a, b) in self.iter_mut().zip(src[mut start..end].iter_mut()) {
+        for (a, b) in self.iter_mut().zip(src.slice_mut(start, end).iter_mut()) {
             mem::swap(a, b);
         }
         cmp::min(self.len(), end-start)
@@ -1326,7 +1326,7 @@ impl<T> BorrowFrom<Vec<T>> for [T] {
 
 #[unstable = "trait is unstable"]
 impl<T> BorrowFromMut<Vec<T>> for [T] {
-    fn borrow_from_mut(owned: &mut Vec<T>) -> &mut [T] { owned[mut] }
+    fn borrow_from_mut(owned: &mut Vec<T>) -> &mut [T] { owned.as_mut_slice_() }
 }
 
 #[unstable = "trait is unstable"]
@@ -2491,14 +2491,14 @@ mod tests {
         assert!(a == [7i,2,3,4]);
         let mut a = [1i,2,3,4,5];
         let b = vec![5i,6,7,8,9,0];
-        assert_eq!(a[mut 2..4].move_from(b,1,6), 2);
+        assert_eq!(a.slice_mut(2, 4).move_from(b,1,6), 2);
         assert!(a == [1i,2,6,7,5]);
     }
 
     #[test]
     fn test_reverse_part() {
         let mut values = [1i,2,3,4,5];
-        values[mut 1..4].reverse();
+        values.slice_mut(1, 4).reverse();
         assert!(values == [1,4,3,2,5]);
     }
 
@@ -2545,9 +2545,9 @@ mod tests {
     fn test_bytes_set_memory() {
         use slice::bytes::MutableByteVector;
         let mut values = [1u8,2,3,4,5];
-        values[mut 0..5].set_memory(0xAB);
+        values.slice_mut(0, 5).set_memory(0xAB);
         assert!(values == [0xAB, 0xAB, 0xAB, 0xAB, 0xAB]);
-        values[mut 2..4].set_memory(0xFF);
+        values.slice_mut(2, 4).set_memory(0xFF);
         assert!(values == [0xAB, 0xAB, 0xFF, 0xFF, 0xAB]);
     }
 

src/libcore/fmt/float.rs

@@ -179,7 +179,7 @@ pub fn float_to_str_bytes_common<T: Float, U, F>(
         _ => ()
     }
 
-    buf[mut ..end].reverse();
+    buf.slice_to_mut(end).reverse();
 
     // Remember start of the fractional digits.
     // Points one beyond end of buf if none get generated,
@@ -316,7 +316,7 @@ pub fn float_to_str_bytes_common<T: Float, U, F>(
 
             impl<'a> fmt::FormatWriter for Filler<'a> {
                 fn write(&mut self, bytes: &[u8]) -> fmt::Result {
-                    slice::bytes::copy_memory(self.buf[mut *self.end..],
+                    slice::bytes::copy_memory(self.buf.slice_from_mut(*self.end),
                                               bytes);
                     *self.end += bytes.len();
                     Ok(())

src/libcore/ops.rs

@@ -908,6 +908,14 @@ impl<Idx: Clone + Step> Iterator<Idx> for RangeFrom<Idx> {
     }
 }
 
+/// A range which is only bounded above.
+#[deriving(Copy)]
+#[lang="range_to"]
+pub struct RangeTo<Idx> {
+    /// The upper bound of the range (exclusive).
+    pub end: Idx,
+}
+
 
 /// The `Deref` trait is used to specify the functionality of dereferencing
 /// operations like `*v`.

src/libcore/slice.rs

@@ -264,24 +264,26 @@ impl<T> SliceExt<T> for [T] {
     fn as_mut_slice(&mut self) -> &mut [T] { self }
 
     fn slice_mut(&mut self, start: uint, end: uint) -> &mut [T] {
-        self[mut start..end]
+        ops::SliceMut::slice_or_fail_mut(self, &start, &end)
     }
 
     #[inline]
     fn slice_from_mut(&mut self, start: uint) -> &mut [T] {
-        self[mut start..]
+        ops::SliceMut::slice_from_or_fail_mut(self, &start)
     }
 
     #[inline]
     fn slice_to_mut(&mut self, end: uint) -> &mut [T] {
-        self[mut ..end]
+        ops::SliceMut::slice_to_or_fail_mut(self, &end)
     }
 
     #[inline]
     fn split_at_mut(&mut self, mid: uint) -> (&mut [T], &mut [T]) {
         unsafe {
             let self2: &mut [T] = mem::transmute_copy(&self);
-            (self[mut ..mid], self2[mut mid..])
+
+            (ops::SliceMut::slice_to_or_fail_mut(self, &mid),
+             ops::SliceMut::slice_from_or_fail_mut(self2, &mid))
         }
     }
 
@@ -315,14 +317,13 @@ impl<T> SliceExt<T> for [T] {
 
     #[inline]
     fn tail_mut(&mut self) -> &mut [T] {
-        let len = self.len();
-        self[mut 1..len]
+        self.slice_from_mut(1)
     }
 
     #[inline]
     fn init_mut(&mut self) -> &mut [T] {
         let len = self.len();
-        self[mut 0..len - 1]
+        self.slice_to_mut(len-1)
     }
 
     #[inline]
@@ -560,7 +561,7 @@ impl<T: Ord> OrdSliceExt<T> for [T] {
         self.swap(j, i-1);
 
         // Step 4: Reverse the (previously) weakly decreasing part
-        self[mut i..].reverse();
+        self.slice_from_mut(i).reverse();
 
         true
     }
@@ -582,7 +583,7 @@ impl<T: Ord> OrdSliceExt<T> for [T] {
         }
 
         // Step 2: Reverse the weakly increasing part
-        self[mut i..].reverse();
+        self.slice_from_mut(i).reverse();
 
         // Step 3: Find the rightmost element equal to or bigger than the pivot (i-1)
         let mut j = self.len() - 1;
@@ -990,7 +991,7 @@ impl<'a, T, P> Iterator<&'a mut [T]> for MutSplits<'a, T, P> where P: FnMut(&T)
             Some(idx) => {
                 let tmp = mem::replace(&mut self.v, &mut []);
                 let (head, tail) = tmp.split_at_mut(idx);
-                self.v = tail[mut 1..];
+                self.v = tail.slice_from_mut(1);
                 Some(head)
             }
         }
@@ -1026,7 +1027,7 @@ impl<'a, T, P> DoubleEndedIterator<&'a mut [T]> for MutSplits<'a, T, P> where
                 let tmp = mem::replace(&mut self.v, &mut []);
                 let (head, tail) = tmp.split_at_mut(idx);
                 self.v = head;
-                Some(tail[mut 1..])
+                Some(tail.slice_from_mut(1))
             }
         }
     }

src/libcore/str/mod.rs

@@ -897,6 +897,7 @@ impl<'a> Iterator<&'a str> for SplitStr<'a> {
     }
 }
 
+
 /*
 Section: Comparing strings
 */

src/libcoretest/ops.rs

@@ -9,7 +9,7 @@
 // except according to those terms.
 
 use test::Bencher;
-use core::ops::{Range, FullRange, RangeFrom};
+use core::ops::{Range, FullRange, RangeFrom, RangeTo};
 
 // Overhead of dtors
 
@@ -55,6 +55,12 @@ fn test_range_from() {
     assert!(count == 10);
 }
 
+#[test]
+fn test_range_to() {
+    // Not much to test.
+    let _ = RangeTo { end: 42u };
+}
+
 #[test]
 fn test_full_range() {
     // Not much to test.

src/libgraphviz/lib.rs

@@ -735,7 +735,7 @@ mod tests {
     fn test_input(g: LabelledGraph) -> IoResult<String> {
         let mut writer = Vec::new();
         render(&g, &mut writer).unwrap();
-        (&mut writer[]).read_to_string()
+        (&mut writer.as_slice()).read_to_string()
     }
 
     // All of the tests use raw-strings as the format for the expected outputs,
@@ -847,7 +847,7 @@ r#"digraph hasse_diagram {
                  edge(1, 3, ";"),    edge(2, 3, ";"   )));
 
         render(&g, &mut writer).unwrap();
-        let r = (&mut writer[]).read_to_string();
+        let r = (&mut writer.as_slice()).read_to_string();
 
         assert_eq!(r.unwrap(),
 r#"digraph syntax_tree {

src/librbml/io.rs

@@ -102,7 +102,7 @@ impl Writer for SeekableMemWriter {
 
             // Do the necessary writes
             if left.len() > 0 {
-                slice::bytes::copy_memory(self.buf[mut self.pos..], left);
+                slice::bytes::copy_memory(self.buf.slice_from_mut(self.pos), left);
             }
             if right.len() > 0 {
                 self.buf.push_all(right);

src/librustc/middle/cfg/construct.rs

@@ -432,15 +432,8 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
                 self.call(expr, pred, &**l, Some(&**r).into_iter())
             }
 
-            ast::ExprSlice(ref base, ref start, ref end, _) => {
-                self.call(expr,
-                          pred,
-                          &**base,
-                          start.iter().chain(end.iter()).map(|x| &**x))
-            }
-
             ast::ExprRange(ref start, ref end) => {
-                let fields = Some(&**start).into_iter()
+                let fields = start.as_ref().map(|e| &**e).into_iter()
                     .chain(end.as_ref().map(|e| &**e).into_iter());
                 self.straightline(expr, pred, fields)
             }

src/librustc/middle/expr_use_visitor.rs

@@ -431,26 +431,33 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
             }
 
             ast::ExprIndex(ref lhs, ref rhs) => {       // lhs[rhs]
-                if !self.walk_overloaded_operator(expr, &**lhs, vec![&**rhs], PassArgs::ByRef) {
-                    self.select_from_expr(&**lhs);
-                    self.consume_expr(&**rhs);
+                match rhs.node {
+                    ast::ExprRange(ref start, ref end) => {
+                        // Hacked slicing syntax (KILLME).
+                        let args = match (start, end) {
+                            (&Some(ref e1), &Some(ref e2)) => vec![&**e1, &**e2],
+                            (&Some(ref e), &None) => vec![&**e],
+                            (&None, &Some(ref e)) => vec![&**e],
+                            (&None, &None) => Vec::new()
+                        };
+                        let overloaded =
+                            self.walk_overloaded_operator(expr, &**lhs, args, PassArgs::ByRef);
+                        assert!(overloaded);
+                    }
+                    _ => {
+                        if !self.walk_overloaded_operator(expr,
+                                                          &**lhs,
+                                                          vec![&**rhs],
+                                                          PassArgs::ByRef) {
+                            self.select_from_expr(&**lhs);
+                            self.consume_expr(&**rhs);
+                        }
+                    }
                 }
             }
 
-            ast::ExprSlice(ref base, ref start, ref end, _) => {    // base[start..end]
-                let args = match (start, end) {
-                    (&Some(ref e1), &Some(ref e2)) => vec![&**e1, &**e2],
-                    (&Some(ref e), &None) => vec![&**e],
-                    (&None, &Some(ref e)) => vec![&**e],
-                    (&None, &None) => Vec::new()
-                };
-                let overloaded =
-                    self.walk_overloaded_operator(expr, &**base, args, PassArgs::ByRef);
-                assert!(overloaded);
-            }
-
             ast::ExprRange(ref start, ref end) => {
-                self.consume_expr(&**start);
+                start.as_ref().map(|e| self.consume_expr(&**e));
                 end.as_ref().map(|e| self.consume_expr(&**e));
             }
 

src/librustc/middle/lang_items.rs

@@ -269,6 +269,7 @@ lets_do_this! {
     SliceMutTraitLangItem,           "slice_mut",               slice_mut_trait;
     RangeStructLangItem,             "range",                   range_struct;
     RangeFromStructLangItem,         "range_from",              range_from_struct;
+    RangeToStructLangItem,           "range_to",                range_to_struct;
     FullRangeStructLangItem,         "full_range",              full_range_struct;
 
     UnsafeTypeLangItem,              "unsafe",                  unsafe_type;

src/librustc/middle/liveness.rs

@@ -514,7 +514,7 @@ fn visit_expr(ir: &mut IrMaps, expr: &Expr) {
       ast::ExprBlock(..) | ast::ExprAssign(..) | ast::ExprAssignOp(..) |
       ast::ExprMac(..) | ast::ExprStruct(..) | ast::ExprRepeat(..) |
       ast::ExprParen(..) | ast::ExprInlineAsm(..) | ast::ExprBox(..) |
-      ast::ExprSlice(..) | ast::ExprRange(..) => {
+      ast::ExprRange(..) => {
           visit::walk_expr(ir, expr);
       }
     }
@@ -1191,15 +1191,9 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
             self.propagate_through_expr(&**l, r_succ)
           }
 
-          ast::ExprSlice(ref e1, ref e2, ref e3, _) => {
-            let succ = e3.as_ref().map_or(succ, |e| self.propagate_through_expr(&**e, succ));
-            let succ = e2.as_ref().map_or(succ, |e| self.propagate_through_expr(&**e, succ));
-            self.propagate_through_expr(&**e1, succ)
-          }
-
           ast::ExprRange(ref e1, ref e2) => {
             let succ = e2.as_ref().map_or(succ, |e| self.propagate_through_expr(&**e, succ));
-            self.propagate_through_expr(&**e1, succ)
+            e1.as_ref().map_or(succ, |e| self.propagate_through_expr(&**e, succ))
           }
 
           ast::ExprBox(None, ref e) |
@@ -1495,7 +1489,7 @@ fn check_expr(this: &mut Liveness, expr: &Expr) {
       ast::ExprBlock(..) | ast::ExprMac(..) | ast::ExprAddrOf(..) |
       ast::ExprStruct(..) | ast::ExprRepeat(..) | ast::ExprParen(..) |
       ast::ExprClosure(..) | ast::ExprPath(..) | ast::ExprBox(..) |
-      ast::ExprSlice(..) | ast::ExprRange(..) => {
+      ast::ExprRange(..) => {
         visit::walk_expr(this, expr);
       }
       ast::ExprIfLet(..) => {