const validation: point at where we found a pointer but expected an integer

Author: RalfJung

src/diagnostics.rs

@@ -273,6 +273,8 @@ pub fn report_error<'tcx, 'mir>(
     } else {
         #[rustfmt::skip]
         let title = match e.kind() {
+            UndefinedBehavior(UndefinedBehaviorInfo::ValidationError(e)) if matches!(e.kind, ValidationErrorKind::PointerAsInt { .. } | ValidationErrorKind::PartialPointer) =>
+                bug!("This validation error should be impossible in Miri: {:?}", e.kind),
             UndefinedBehavior(_) =>
                 "Undefined Behavior",
             ResourceExhaustion(_) =>
@@ -377,7 +379,7 @@ pub fn report_error<'tcx, 'mir>(
     if let Some((alloc_id, access)) = extra {
         eprintln!(
             "Uninitialized memory occurred at {alloc_id:?}{range:?}, in this allocation:",
-            range = access.uninit,
+            range = access.bad,
         );
         eprintln!("{:?}", ecx.dump_alloc(alloc_id));
     }

tests/fail/validity/uninit_float.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: constructing invalid value at .value[0]: encountered uninitialized bytes
+error: Undefined Behavior: constructing invalid value at .value[0]: encountered uninitialized memory, but expected a floating point number
   --> $DIR/uninit_float.rs:LL:CC
    |
 LL |     let _val: [f32; 1] = unsafe { std::mem::uninitialized() };
-   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .value[0]: encountered uninitialized bytes
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .value[0]: encountered uninitialized memory, but expected a floating point number
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

tests/fail/validity/uninit_integer.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: constructing invalid value at .value[0]: encountered uninitialized bytes
+error: Undefined Behavior: constructing invalid value at .value[0]: encountered uninitialized memory, but expected an integer
   --> $DIR/uninit_integer.rs:LL:CC
    |
 LL |     let _val = unsafe { std::mem::MaybeUninit::<[usize; 1]>::uninit().assume_init() };
-   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .value[0]: encountered uninitialized bytes
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .value[0]: encountered uninitialized memory, but expected an integer
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information