fix silent overflows on Step impls

r? @eddyb
rust-lang · Sep 9, 2016 · f6c4fcf · f6c4fcf
1 parent f1f40f8
commit f6c4fcf
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Showing 2 changed files with 20 additions and 0 deletions.
diff --git a/src/libcore/iter/range.rs b/src/libcore/iter/range.rs
@@ -95,11 +95,13 @@ macro_rules! step_impl_unsigned {
             }
 
             #[inline]
+            #[rustc_inherit_overflow_checks]
             fn add_one(&self) -> Self {
                 *self + 1
             }
 
             #[inline]
+            #[rustc_inherit_overflow_checks]
             fn sub_one(&self) -> Self {
                 *self - 1
             }
@@ -166,11 +168,13 @@ macro_rules! step_impl_signed {
             }
 
             #[inline]
+            #[rustc_inherit_overflow_checks]
             fn add_one(&self) -> Self {
                 *self + 1
             }
 
             #[inline]
+            #[rustc_inherit_overflow_checks]
             fn sub_one(&self) -> Self {
                 *self - 1
             }
@@ -215,11 +219,13 @@ macro_rules! step_impl_no_between {
             }
 
             #[inline]
+            #[rustc_inherit_overflow_checks]
             fn add_one(&self) -> Self {
                 *self + 1
             }
 
             #[inline]
+            #[rustc_inherit_overflow_checks]
             fn sub_one(&self) -> Self {
                 *self - 1
             }

diff --git a/src/libcoretest/iter.rs b/src/libcoretest/iter.rs
@@ -915,6 +915,20 @@ fn test_range_step() {
     assert_eq!((isize::MIN..isize::MAX).step_by(1).size_hint(), (usize::MAX, Some(usize::MAX)));
 }
 
+#[test]
+#[should_panic]
+fn test_range_overflow_unsigned() {
+    let mut it = u8::MAX..;
+    it.next();
+}
+
+#[test]
+#[should_panic]
+fn test_range_overflow_signed() {
+    let mut it = i8::MAX..;
+    it.next();
+}
+
 #[test]
 fn test_repeat() {
     let mut it = repeat(42);