Rollup merge of #70283 - CDirkx:regression-test-70155, r=oli-obk

Add regression test for #70155.

With #70166 merged, `RangeInclusive` now derives `PartialEq` and `Eq`, implementing structural equality and as a side effect the range is now usable with const generics, closing #70155.

As per [#70166 (comment)](https://github.com/rust-lang/rust/pull/70166#issuecomment-601872201) a test is added to avoid a change to the private fields or the equality implementation of the range from subtly reverting #70155.

src/test/ui/const-generics/std/const-generics-range.rs

@@ -0,0 +1,30 @@
+// check-pass
+#![allow(incomplete_features)]
+#![feature(const_generics)]
+
+// `Range` should be usable within const generics:
+struct _Range<const R: std::ops::Range<usize>>;
+const RANGE : _Range<{ 0 .. 1000 }> = _Range;
+
+// `RangeFrom` should be usable within const generics:
+struct _RangeFrom<const R: std::ops::RangeFrom<usize>>;
+const RANGE_FROM : _RangeFrom<{ 0 .. }> = _RangeFrom;
+
+// `RangeFull` should be usable within const generics:
+struct _RangeFull<const R: std::ops::RangeFull>;
+const RANGE_FULL : _RangeFull<{ .. }> = _RangeFull;
+
+// Regression test for #70155
+// `RangeInclusive` should be usable within const generics:
+struct _RangeInclusive<const R: std::ops::RangeInclusive<usize>>;
+const RANGE_INCLUSIVE : _RangeInclusive<{ 0 ..= 999 }> = _RangeInclusive;
+
+// `RangeTo` should be usable within const generics:
+struct _RangeTo<const R: std::ops::RangeTo<usize>>;
+const RANGE_TO : _RangeTo<{ .. 1000 }> = _RangeTo;
+
+// `RangeToInclusive` should be usable within const generics:
+struct _RangeToInclusive<const R: std::ops::RangeToInclusive<usize>>;
+const RANGE_TO_INCLUSIVE : _RangeToInclusive<{ ..= 999 }> = _RangeToInclusive;
+
+pub fn main() {}