Rollup merge of rust-lang#78738 - sasurau4:test/move-range-test-to-li…

…brary-core, r=jyn514

Move range in ui test to ops test in library/core

Helps with rust-lang#76268

r? ````@matklad````

library/core/tests/ops.rs

@@ -1,6 +1,6 @@
 use core::ops::{Bound, Range, RangeFrom, RangeFull, RangeInclusive, RangeTo};
 
-// Test the Range structs without the syntactic sugar.
+// Test the Range structs and syntax.
 
 #[test]
 fn test_range() {
@@ -94,3 +94,60 @@ fn test_bound_cloned_included() {
 fn test_bound_cloned_excluded() {
     assert_eq!(Bound::Excluded(&3).cloned(), Bound::Excluded(3));
 }
+
+#[test]
+#[allow(unused_comparisons)]
+#[allow(unused_mut)]
+fn test_range_syntax() {
+    let mut count = 0;
+    for i in 0_usize..10 {
+        assert!(i >= 0 && i < 10);
+        count += i;
+    }
+    assert_eq!(count, 45);
+
+    let mut count = 0;
+    let mut range = 0_usize..10;
+    for i in range {
+        assert!(i >= 0 && i < 10);
+        count += i;
+    }
+    assert_eq!(count, 45);
+
+    let mut count = 0;
+    let mut rf = 3_usize..;
+    for i in rf.take(10) {
+        assert!(i >= 3 && i < 13);
+        count += i;
+    }
+    assert_eq!(count, 75);
+
+    let _ = 0_usize..4 + 4 - 3;
+
+    fn foo() -> isize {
+        42
+    }
+    let _ = 0..foo();
+
+    let _ = { &42..&100 }; // references to literals are OK
+    let _ = ..42_usize;
+
+    // Test we can use two different types with a common supertype.
+    let x = &42;
+    {
+        let y = 42;
+        let _ = x..&y;
+    }
+}
+
+#[test]
+#[allow(dead_code)]
+fn test_range_syntax_in_return_statement() {
+    fn return_range_to() -> RangeTo<i32> {
+        return ..1;
+    }
+    fn return_full_range() -> RangeFull {
+        return ..;
+    }
+    // Not much to test.
+}