Auto merge of rust-lang#131006 - RalfJung:immediate-sanity, r=<try>

interpret: always enable write_immediate sanity checks

Writing a wrongly-sized scalar somewhere can have quite confusing effects. Let's see how expensive it is to catch this early.

Author: bors

compiler/rustc_const_eval/src/interpret/place.rs

@@ -652,9 +652,7 @@ where
                     M::after_local_write(self, local, /*storage_live*/ false)?;
                 }
                 // Double-check that the value we are storing and the local fit to each other.
-                if cfg!(debug_assertions) {
-                    src.assert_matches_abi(local_layout.abi, self);
-                }
+                src.assert_matches_abi(local_layout.abi, self);
             }
             Left(mplace) => {
                 self.write_immediate_to_mplace_no_validate(src, mplace.layout, mplace.mplace)?;
@@ -672,9 +670,8 @@ where
         layout: TyAndLayout<'tcx>,
         dest: MemPlace<M::Provenance>,
     ) -> InterpResult<'tcx> {
-        if cfg!(debug_assertions) {
-            value.assert_matches_abi(layout.abi, self);
-        }
+        // Ensure the value matches the type of the place it is written to.
+        value.assert_matches_abi(layout.abi, self);
         // Note that it is really important that the type here is the right one, and matches the
         // type things are read at. In case `value` is a `ScalarPair`, we don't do any magic here
         // to handle padding properly, which is only correct if we never look at this data with the