Auto merge of rust-lang#116930 - RalfJung:raw-ptr-match, r=davidtwco

patterns: reject raw pointers that are not just integers

Matching against `0 as *const i32` is fine, matching against `&42 as *const i32` is not.

This extends the existing check against function pointers and wide pointers: we now uniformly reject all these pointer types during valtree construction, and then later lint because of that. See [here](rust-lang#116930 (comment)) for some more explanation and context.

Also fixes rust-lang#116929.

Cc `@oli-obk` `@lcnr`

Author: bors

core/src/marker.rs

@@ -253,6 +253,7 @@ marker_impls! {
 ///
 /// const CFN: Wrap<fn(&())> = Wrap(higher_order);
 ///
+/// #[allow(pointer_structural_match)]
 /// fn main() {
 ///     match CFN {
 ///         CFN => {}