Rollup merge of rust-lang#142339 - oli-obk:not-null-pattern-types, r=BoxyUwU

Add NonNull pattern types

These are the final piece missing for

* rust-lang#136006

We cannot use the previous scheme of using an integer range for raw pointers, as we're not just changing the layout of raw pointers anymore, but also the type representation. And we can't represent "any provenance or NonZero<usize>" natively as patterns. So I created a new `!null` pattern. Since this is all unstable representation stuff for replacing rustc_layout_scalar_range_start with pattern types, the divergence from normal patterns is fine, especially since T-lang seems interested in exploring general negation patterns

r? `@BoxyUwU`

Author: matthiaskrgr

core/src/lib.rs

@@ -116,6 +116,7 @@
 #![feature(link_cfg)]
 #![feature(offset_of_enum)]
 #![feature(panic_internals)]
+#![feature(pattern_type_macro)]
 #![feature(ptr_alignment_type)]
 #![feature(ptr_metadata)]
 #![feature(set_ptr_value)]
@@ -171,6 +172,7 @@
 #![feature(never_type)]
 #![feature(no_core)]
 #![feature(optimize_attribute)]
+#![feature(pattern_types)]
 #![feature(prelude_import)]
 #![feature(reborrow)]
 #![feature(repr_simd)]

core/src/pat.rs

@@ -1,5 +1,8 @@
 //! Helper module for exporting the `pattern_type` macro
 
+use crate::marker::{Freeze, PointeeSized, Unsize};
+use crate::ops::{CoerceUnsized, DispatchFromDyn};
+
 /// Creates a pattern type.
 /// ```ignore (cannot test this from within core yet)
 /// type Positive = std::pat::pattern_type!(i32 is 1..);
@@ -73,3 +76,16 @@ impl const RangePattern for char {
         }
     }
 }
+
+impl<T: PointeeSized, U: PointeeSized> CoerceUnsized<pattern_type!(*const U is !null)> for pattern_type!(*const T is !null) where
+    T: Unsize<U>
+{
+}
+
+impl<T: DispatchFromDyn<U>, U> DispatchFromDyn<pattern_type!(U is !null)> for pattern_type!(T is !null) {}
+
+impl<T: PointeeSized> Unpin for pattern_type!(*const T is !null) {}
+
+unsafe impl<T: PointeeSized> Freeze for pattern_type!(*const T is !null) {}
+
+unsafe impl<T: PointeeSized> Freeze for pattern_type!(*mut T is !null) {}