Rollup merge of #100181 - RalfJung:alloc-ref-mutability, r=jackh726

add method to get the mutability of an AllocId

Miri needs this for rust-lang/miri#2463.

compiler/rustc_const_eval/src/interpret/memory.rs

@@ -520,6 +520,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
 
     /// Gives raw access to the `Allocation`, without bounds or alignment checks.
     /// The caller is responsible for calling the access hooks!
+    ///
+    /// You almost certainly want to use `get_ptr_alloc`/`get_ptr_alloc_mut` instead.
     fn get_alloc_raw(
         &self,
         id: AllocId,
@@ -589,6 +591,11 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         Ok(&self.get_alloc_raw(id)?.extra)
     }
 
+    /// Return the `mutability` field of the given allocation.
+    pub fn get_alloc_mutability<'a>(&'a self, id: AllocId) -> InterpResult<'tcx, Mutability> {
+        Ok(self.get_alloc_raw(id)?.mutability)
+    }
+
     /// Gives raw mutable access to the `Allocation`, without bounds or alignment checks.
     /// The caller is responsible for calling the access hooks!
     ///

src/bootstrap/test.rs

@@ -628,6 +628,10 @@ impl Step for Miri {
             cargo.env("MIRI_HOST_SYSROOT", sysroot);
             cargo.env("RUSTC_LIB_PATH", builder.rustc_libdir(compiler));
             cargo.env("MIRI", miri);
+            // propagate --bless
+            if builder.config.cmd.bless() {
+                cargo.env("MIRI_BLESS", "Gesundheit");
+            }
 
             cargo.arg("--").args(builder.config.cmd.test_args());