Rollup merge of #114372 - RalfJung:const-pointer-as-int, r=oli-obk

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

Instead of validation just printing "unable to turn pointer into bytes", make this a regular validation error that says where in the value the bad pointer was found. Also distinguish "expected integer, got pointer" from "expected pointer, got partial pointer or mix of pointers".

To avoid duplicating things too much I refactored the diagnostics for validity a bit, so that "got uninit, expected X" and "got pointer, expected X" can share the "X" part. Also all the errors emitted for validation are now grouped under `const_eval_validation` so that they are in a single group in the ftl file.

r? `@oli-obk`

Author: matthiaskrgr

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