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`

compiler/rustc_middle/src/mir/interpret/error.rs

@@ -134,10 +134,6 @@ impl InterpErrorBacktrace {
 }
 
 impl<'tcx> InterpErrorInfo<'tcx> {
-    pub fn from_parts(kind: InterpError<'tcx>, backtrace: InterpErrorBacktrace) -> Self {
-        Self(Box::new(InterpErrorInfoInner { kind, backtrace }))
-    }
-
     pub fn into_parts(self) -> (InterpError<'tcx>, InterpErrorBacktrace) {
         let InterpErrorInfo(box InterpErrorInfoInner { kind, backtrace }) = self;
         (kind, backtrace)
@@ -226,13 +222,13 @@ impl IntoDiagnosticArg for InvalidMetaKind {
     }
 }
 
-/// Details of an access to uninitialized bytes where it is not allowed.
+/// Details of an access to uninitialized bytes / bad pointer bytes where it is not allowed.
 #[derive(Debug, Clone, Copy)]
-pub struct UninitBytesAccess {
+pub struct BadBytesAccess {
     /// Range of the original memory access.
     pub access: AllocRange,
-    /// Range of the uninit memory that was encountered. (Might not be maximal.)
-    pub uninit: AllocRange,
+    /// Range of the bad memory that was encountered. (Might not be maximal.)
+    pub bad: AllocRange,
 }
 
 /// Information about a size mismatch.
@@ -316,7 +312,7 @@ pub enum UndefinedBehaviorInfo<'a> {
     /// Using a string that is not valid UTF-8,
     InvalidStr(std::str::Utf8Error),
     /// Using uninitialized data where it is not allowed.
-    InvalidUninitBytes(Option<(AllocId, UninitBytesAccess)>),
+    InvalidUninitBytes(Option<(AllocId, BadBytesAccess)>),
     /// Working with a local that is not currently live.
     DeadLocal,
     /// Data size is not equal to target size.
@@ -326,7 +322,7 @@ pub enum UndefinedBehaviorInfo<'a> {
     /// An uninhabited enum variant is projected.
     UninhabitedEnumVariantRead(VariantIdx),
     /// Validation error.
-    Validation(ValidationErrorInfo<'a>),
+    ValidationError(ValidationErrorInfo<'a>),
     // FIXME(fee1-dead) these should all be actual variants of the enum instead of dynamically
     // dispatched
     /// A custom (free-form) error, created by `err_ub_custom!`.
@@ -368,6 +364,8 @@ pub enum ExpectedKind {
     Float,
     Int,
     FnPtr,
+    EnumTag,
+    Str,
 }
 
 impl From<PointerKind> for ExpectedKind {
@@ -381,10 +379,11 @@ impl From<PointerKind> for ExpectedKind {
 
 #[derive(Debug)]
 pub enum ValidationErrorKind<'tcx> {
+    PointerAsInt { expected: ExpectedKind },
+    PartialPointer,
     PtrToUninhabited { ptr_kind: PointerKind, ty: Ty<'tcx> },
     PtrToStatic { ptr_kind: PointerKind },
     PtrToMut { ptr_kind: PointerKind },
-    ExpectedNonPtr { value: String },
     MutableRefInConst,
     NullFnPtr,
     NeverVal,
@@ -394,11 +393,8 @@ pub enum ValidationErrorKind<'tcx> {
     UnsafeCell,
     UninhabitedVal { ty: Ty<'tcx> },
     InvalidEnumTag { value: String },
-    UninhabitedEnumTag,
-    UninitEnumTag,
-    UninitStr,
+    UninhabitedEnumVariant,
     Uninit { expected: ExpectedKind },
-    UninitVal,
     InvalidVTablePtr { value: String },
     InvalidMetaSliceTooLarge { ptr_kind: PointerKind },
     InvalidMetaTooLarge { ptr_kind: PointerKind },
@@ -426,12 +422,12 @@ pub enum UnsupportedOpInfo {
     //
     /// Overwriting parts of a pointer; without knowing absolute addresses, the resulting state
     /// cannot be represented by the CTFE interpreter.
-    PartialPointerOverwrite(Pointer<AllocId>),
-    /// Attempting to `copy` parts of a pointer to somewhere else; without knowing absolute
+    OverwritePartialPointer(Pointer<AllocId>),
+    /// Attempting to read or copy parts of a pointer to somewhere else; without knowing absolute
     /// addresses, the resulting state cannot be represented by the CTFE interpreter.
-    PartialPointerCopy(Pointer<AllocId>),
-    /// Encountered a pointer where we needed raw bytes.
-    ReadPointerAsBytes,
+    ReadPartialPointer(Pointer<AllocId>),
+    /// Encountered a pointer where we needed an integer.
+    ReadPointerAsInt(Option<(AllocId, BadBytesAccess)>),
     /// Accessing thread local statics
     ThreadLocalStatic(DefId),
     /// Accessing an unsupported extern static.
@@ -497,7 +493,7 @@ impl InterpError<'_> {
         matches!(
             self,
             InterpError::Unsupported(UnsupportedOpInfo::Unsupported(_))
-                | InterpError::UndefinedBehavior(UndefinedBehaviorInfo::Validation { .. })
+                | InterpError::UndefinedBehavior(UndefinedBehaviorInfo::ValidationError { .. })
                 | InterpError::UndefinedBehavior(UndefinedBehaviorInfo::Ub(_))
         )
     }