Make RangeInclusive just a two-field struct

Not being an enum improves ergonomics, especially since NonEmpty could be Empty.  It can still be iterable without an extra "done" bit by making the range have !(start <= end), which is even possible without changing the Step trait.

Implements RFC 1980

2 files changed, 18 insertions, 1 deletions

diff --git a/src/libcore/tests/lib.rs b/src/libcore/tests/lib.rs
index c52155ead4f..8c4cd1d0c84 100644
--- a/src/libcore/tests/lib.rs
+++ b/src/libcore/tests/lib.rs
@@ -22,6 +22,7 @@
 #![feature(fmt_internals)]
 #![feature(iterator_step_by)]
 #![feature(i128_type)]
+#![feature(inclusive_range)]
 #![feature(iter_rfind)]
 #![feature(libc)]
 #![feature(nonzero)]
diff --git a/src/libcore/tests/ops.rs b/src/libcore/tests/ops.rs
index 1c6c13b0d02..50aed15896c 100644
--- a/src/libcore/tests/ops.rs
+++ b/src/libcore/tests/ops.rs
@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use core::ops::{Range, RangeFull, RangeFrom, RangeTo};
+use core::ops::{Range, RangeFull, RangeFrom, RangeTo, RangeInclusive};
 
 // Test the Range structs without the syntactic sugar.
 
@@ -47,3 +47,19 @@ fn test_full_range() {
     // Not much to test.
     let _ = RangeFull;
 }
+
+#[test]
+fn test_range_inclusive() {
+    let mut r = RangeInclusive { start: 1i8, end: 2 };
+    assert_eq!(r.next(), Some(1));
+    assert_eq!(r.next(), Some(2));
+    assert_eq!(r.next(), None);
+
+    r = RangeInclusive { start: 127i8, end: 127 };
+    assert_eq!(r.next(), Some(127));
+    assert_eq!(r.next(), None);
+
+    r = RangeInclusive { start: -128i8, end: -128 };
+    assert_eq!(r.next_back(), Some(-128));
+    assert_eq!(r.next_back(), None);
+}
\ No newline at end of file