Auto merge of #119274 - RalfJung:raw-ptr-pattern-ice, r=compiler-errors

fix ICE when using raw ptr in a pattern

Fixes https://github.com/rust-lang/rust/issues/119270

compiler/rustc_const_eval/src/const_eval/valtrees.rs

@@ -341,7 +341,7 @@ fn valtree_into_mplace<'tcx>(
         ty::FnDef(_, _) => {
             // Zero-sized type, nothing to do.
         }
-        ty::Bool | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Char => {
+        ty::Bool | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Char | ty::RawPtr(..) => {
             let scalar_int = valtree.unwrap_leaf();
             debug!("writing trivial valtree {:?} to place {:?}", scalar_int, place);
             ecx.write_immediate(Immediate::Scalar(scalar_int.into()), place).unwrap();

tests/ui/consts/const_in_pattern/null-raw-ptr-issue-119270.rs

@@ -0,0 +1,19 @@
+// run-pass
+// Eventually this will be rejected (when the future-compat lints are turned into hard errors), and
+// then this test can be removed. But meanwhile we should ensure that this works and does not ICE.
+struct NoDerive(i32);
+
+#[derive(PartialEq)]
+struct WrapEmbedded(*const NoDerive);
+
+const WRAP_UNSAFE_EMBEDDED: &&WrapEmbedded = &&WrapEmbedded(std::ptr::null());
+
+fn main() {
+    let b = match WRAP_UNSAFE_EMBEDDED {
+        WRAP_UNSAFE_EMBEDDED => true,
+        //~^ WARN: must be annotated with `#[derive(PartialEq, Eq)]`
+        //~| previously accepted
+        _ => false,
+    };
+    assert!(b);
+}

tests/ui/consts/const_in_pattern/null-raw-ptr-issue-119270.stderr

@@ -0,0 +1,14 @@
+warning: to use a constant of type `WrapEmbedded` in a pattern, `WrapEmbedded` must be annotated with `#[derive(PartialEq, Eq)]`
+  --> $DIR/null-raw-ptr-issue-119270.rs:13:9
+   |
+LL |         WRAP_UNSAFE_EMBEDDED => true,
+   |         ^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #62411 <https://github.com/rust-lang/rust/issues/62411>
+   = note: the traits must be derived, manual `impl`s are not sufficient
+   = note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralEq.html for details
+   = note: `#[warn(indirect_structural_match)]` on by default
+
+warning: 1 warning emitted
+