Auto merge of #87029 - JohnTitor:rollup-0yapv7z, r=JohnTitor

Rollup of 5 pull requests

Successful merges:

 - #87006 (Revert the revert of renaming traits::VTable to ImplSource)
 - #87011 (avoid reentrant lock acquire when ThreadIds run out)
 - #87013 (Fix several ICEs related to malformed `#[repr(...)]` attributes)
 - #87020 (remove const_raw_ptr_to_usize_cast feature)
 - #87028 (Fix type: `'satic` -> `'static`)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

44 files changed, 305 insertions, 346 deletions

diff --git a/compiler/rustc_attr/src/builtin.rs b/compiler/rustc_attr/src/builtin.rs
index 20971ebb957..b7b053cd5dd 100644
--- a/compiler/rustc_attr/src/builtin.rs
+++ b/compiler/rustc_attr/src/builtin.rs
@@ -870,6 +870,23 @@ pub fn find_repr_attrs(sess: &Session, attr: &Attribute) -> Vec<ReprAttr> {
                         sym::simd => Some(ReprSimd),
                         sym::transparent => Some(ReprTransparent),
                         sym::no_niche => Some(ReprNoNiche),
+                        sym::align => {
+                            let mut err = struct_span_err!(
+                                diagnostic,
+                                item.span(),
+                                E0589,
+                                "invalid `repr(align)` attribute: `align` needs an argument"
+                            );
+                            err.span_suggestion(
+                                item.span(),
+                                "supply an argument here",
+                                "align(...)".to_string(),
+                                Applicability::HasPlaceholders,
+                            );
+                            err.emit();
+                            recognised = true;
+                            None
+                        }
                         name => int_type_of_word(name).map(ReprInt),
                     };
 
@@ -891,33 +908,47 @@ pub fn find_repr_attrs(sess: &Session, attr: &Attribute) -> Vec<ReprAttr> {
                             Ok(literal) => acc.push(ReprPacked(literal)),
                             Err(message) => literal_error = Some(message),
                         };
+                    } else if matches!(name, sym::C | sym::simd | sym::transparent | sym::no_niche)
+                        || int_type_of_word(name).is_some()
+                    {
+                        recognised = true;
+                        struct_span_err!(
+                                diagnostic,
+                                item.span(),
+                                E0552,
+                                "invalid representation hint: `{}` does not take a parenthesized argument list",
+                                name.to_ident_string(),
+                            ).emit();
                     }
                     if let Some(literal_error) = literal_error {
                         struct_span_err!(
                             diagnostic,
                             item.span(),
                             E0589,
-                            "invalid `repr(align)` attribute: {}",
+                            "invalid `repr({})` attribute: {}",
+                            name.to_ident_string(),
                             literal_error
                         )
                         .emit();
                     }
                 } else if let Some(meta_item) = item.meta_item() {
-                    if meta_item.has_name(sym::align) {
-                        if let MetaItemKind::NameValue(ref value) = meta_item.kind {
+                    if let MetaItemKind::NameValue(ref value) = meta_item.kind {
+                        if meta_item.has_name(sym::align) || meta_item.has_name(sym::packed) {
+                            let name = meta_item.name_or_empty().to_ident_string();
                             recognised = true;
                             let mut err = struct_span_err!(
                                 diagnostic,
                                 item.span(),
                                 E0693,
-                                "incorrect `repr(align)` attribute format"
+                                "incorrect `repr({})` attribute format",
+                                name,
                             );
                             match value.kind {
                                 ast::LitKind::Int(int, ast::LitIntType::Unsuffixed) => {
                                     err.span_suggestion(
                                         item.span(),
                                         "use parentheses instead",
-                                        format!("align({})", int),
+                                        format!("{}({})", name, int),
                                         Applicability::MachineApplicable,
                                     );
                                 }
@@ -925,19 +956,76 @@ pub fn find_repr_attrs(sess: &Session, attr: &Attribute) -> Vec<ReprAttr> {
                                     err.span_suggestion(
                                         item.span(),
                                         "use parentheses instead",
-                                        format!("align({})", s),
+                                        format!("{}({})", name, s),
                                         Applicability::MachineApplicable,
                                     );
                                 }
                                 _ => {}
                             }
                             err.emit();
+                        } else {
+                            if matches!(
+                                meta_item.name_or_empty(),
+                                sym::C | sym::simd | sym::transparent | sym::no_niche
+                            ) || int_type_of_word(meta_item.name_or_empty()).is_some()
+                            {
+                                recognised = true;
+                                struct_span_err!(
+                                    diagnostic,
+                                    meta_item.span,
+                                    E0552,
+                                    "invalid representation hint: `{}` does not take a value",
+                                    meta_item.name_or_empty().to_ident_string(),
+                                )
+                                .emit();
+                            }
+                        }
+                    } else if let MetaItemKind::List(_) = meta_item.kind {
+                        if meta_item.has_name(sym::align) {
+                            recognised = true;
+                            struct_span_err!(
+                                diagnostic,
+                                meta_item.span,
+                                E0693,
+                                "incorrect `repr(align)` attribute format: \
+                                 `align` takes exactly one argument in parentheses"
+                            )
+                            .emit();
+                        } else if meta_item.has_name(sym::packed) {
+                            recognised = true;
+                            struct_span_err!(
+                                diagnostic,
+                                meta_item.span,
+                                E0552,
+                                "incorrect `repr(packed)` attribute format: \
+                                 `packed` takes exactly one parenthesized argument, \
+                                 or no parentheses at all"
+                            )
+                            .emit();
+                        } else if matches!(
+                            meta_item.name_or_empty(),
+                            sym::C | sym::simd | sym::transparent | sym::no_niche
+                        ) || int_type_of_word(meta_item.name_or_empty()).is_some()
+                        {
+                            recognised = true;
+                            struct_span_err!(
+                                diagnostic,
+                                meta_item.span,
+                                E0552,
+                                "invalid representation hint: `{}` does not take a parenthesized argument list",
+                                meta_item.name_or_empty().to_ident_string(),
+                            ).emit();
                         }
                     }
                 }
                 if !recognised {
-                    // Not a word we recognize
-                    diagnostic.delay_span_bug(item.span(), "unrecognized representation hint");
+                    // Not a word we recognize. This will be caught and reported by
+                    // the `check_mod_attrs` pass, but this pass doesn't always run
+                    // (e.g. if we only pretty-print the source), so we have to gate
+                    // the `delay_span_bug` call as follows:
+                    if sess.opts.pretty.map_or(true, |pp| pp.needs_analysis()) {
+                        diagnostic.delay_span_bug(item.span(), "unrecognized representation hint");
+                    }
                 }
             }
         }
diff --git a/compiler/rustc_feature/src/active.rs b/compiler/rustc_feature/src/active.rs
index d01804aca88..9eaf4693811 100644
--- a/compiler/rustc_feature/src/active.rs
+++ b/compiler/rustc_feature/src/active.rs
@@ -416,9 +416,6 @@ declare_features! (
     /// Allows accessing fields of unions inside `const` functions.
     (active, const_fn_union, "1.27.0", Some(51909), None),
 
-    /// Allows casting raw pointers to `usize` during const eval.
-    (active, const_raw_ptr_to_usize_cast, "1.27.0", Some(51910), None),
-
     /// Allows dereferencing raw pointers during const eval.
     (active, const_raw_ptr_deref, "1.27.0", Some(51911), None),
 
diff --git a/compiler/rustc_feature/src/removed.rs b/compiler/rustc_feature/src/removed.rs
index 71c10eb6507..6d3e2b9c517 100644
--- a/compiler/rustc_feature/src/removed.rs
+++ b/compiler/rustc_feature/src/removed.rs
@@ -144,6 +144,10 @@ declare_features! (
     (removed, external_doc, "1.54.0", Some(44732), None,
      Some("use #[doc = include_str!(\"filename\")] instead, which handles macro invocations")),
 
+     /// Allows casting raw pointers to `usize` during const eval.
+    (removed, const_raw_ptr_to_usize_cast, "1.55.0", Some(51910), None,
+     Some("at compile-time, pointers do not have an integer value, so these casts cannot be properly supported")),
+
     // -------------------------------------------------------------------------
     // feature-group-end: removed features
     // -------------------------------------------------------------------------
diff --git a/compiler/rustc_middle/src/traits/mod.rs b/compiler/rustc_middle/src/traits/mod.rs
index c9b73c68209..892a29e4e22 100644
--- a/compiler/rustc_middle/src/traits/mod.rs
+++ b/compiler/rustc_middle/src/traits/mod.rs
@@ -426,10 +426,10 @@ pub type SelectionResult<'tcx, T> = Result<Option<T>, SelectionError<'tcx>>;
 /// impl Clone for i32 { ... }                   // Impl_3
 ///
 /// fn foo<T: Clone>(concrete: Option<Box<i32>>, param: T, mixed: Option<T>) {
-///     // Case A: Vtable points at a specific impl. Only possible when
+///     // Case A: ImplSource points at a specific impl. Only possible when
 ///     // type is concretely known. If the impl itself has bounded
-///     // type parameters, Vtable will carry resolutions for those as well:
-///     concrete.clone(); // Vtable(Impl_1, [Vtable(Impl_2, [Vtable(Impl_3)])])
+///     // type parameters, ImplSource will carry resolutions for those as well:
+///     concrete.clone(); // ImpleSource(Impl_1, [ImplSource(Impl_2, [ImplSource(Impl_3)])])
 ///
 ///     // Case A: ImplSource points at a specific impl. Only possible when
 ///     // type is concretely known. If the impl itself has bounded
diff --git a/compiler/rustc_mir/src/transform/check_consts/ops.rs b/compiler/rustc_mir/src/transform/check_consts/ops.rs
index dcbc9c523dc..fd72ec4340f 100644
--- a/compiler/rustc_mir/src/transform/check_consts/ops.rs
+++ b/compiler/rustc_mir/src/transform/check_consts/ops.rs
@@ -397,6 +397,9 @@ impl NonConstOp for PanicNonStr {
     }
 }
 
+/// Comparing raw pointers for equality.
+/// Not currently intended to ever be allowed, even behind a feature gate: operation depends on
+/// allocation base addresses that are not known at compile-time.
 #[derive(Debug)]
 pub struct RawPtrComparison;
 impl NonConstOp for RawPtrComparison {
@@ -430,20 +433,22 @@ impl NonConstOp for RawPtrDeref {
     }
 }
 
+/// Casting raw pointer or function pointer to an integer.
+/// Not currently intended to ever be allowed, even behind a feature gate: operation depends on
+/// allocation base addresses that are not known at compile-time.
 #[derive(Debug)]
 pub struct RawPtrToIntCast;
 impl NonConstOp for RawPtrToIntCast {
-    fn status_in_item(&self, _: &ConstCx<'_, '_>) -> Status {
-        Status::Unstable(sym::const_raw_ptr_to_usize_cast)
-    }
-
     fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
-        feature_err(
-            &ccx.tcx.sess.parse_sess,
-            sym::const_raw_ptr_to_usize_cast,
-            span,
-            &format!("casting pointers to integers in {}s is unstable", ccx.const_kind(),),
-        )
+        let mut err = ccx
+            .tcx
+            .sess
+            .struct_span_err(span, "pointers cannot be cast to integers during const eval.");
+        err.note("at compile-time, pointers do not have an integer value");
+        err.note(
+            "avoiding this restriction via `transmute`, `union`, or raw pointers leads to compile-time undefined behavior",
+        );
+        err
     }
 }
 
diff --git a/compiler/rustc_mir/src/transform/check_unsafety.rs b/compiler/rustc_mir/src/transform/check_unsafety.rs
index 103ddda1a1d..1ff9bd15721 100644
--- a/compiler/rustc_mir/src/transform/check_unsafety.rs
+++ b/compiler/rustc_mir/src/transform/check_unsafety.rs
@@ -7,7 +7,6 @@ use rustc_hir::intravisit;
 use rustc_hir::Node;
 use rustc_middle::mir::visit::{MutatingUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::*;
-use rustc_middle::ty::cast::CastTy;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_session::lint::builtin::{UNSAFE_OP_IN_UNSAFE_FN, UNUSED_UNSAFE};
@@ -18,7 +17,6 @@ use std::ops::Bound;
 pub struct UnsafetyChecker<'a, 'tcx> {
     body: &'a Body<'tcx>,
     body_did: LocalDefId,
-    const_context: bool,
     violations: Vec<UnsafetyViolation>,
     source_info: SourceInfo,
     tcx: TyCtxt<'tcx>,
@@ -30,7 +28,6 @@ pub struct UnsafetyChecker<'a, 'tcx> {
 
 impl<'a, 'tcx> UnsafetyChecker<'a, 'tcx> {
     fn new(
-        const_context: bool,
         body: &'a Body<'tcx>,
         body_did: LocalDefId,
         tcx: TyCtxt<'tcx>,
@@ -39,7 +36,6 @@ impl<'a, 'tcx> UnsafetyChecker<'a, 'tcx> {
         Self {
             body,
             body_did,
-            const_context,
             violations: vec![],
             source_info: SourceInfo::outermost(body.span),
             tcx,
@@ -136,25 +132,6 @@ impl<'a, 'tcx> Visitor<'tcx> for UnsafetyChecker<'a, 'tcx> {
                     self.register_violations(&violations, &unsafe_blocks);
                 }
             },
-            // casting pointers to ints is unsafe in const fn because the const evaluator cannot
-            // possibly know what the result of various operations like `address / 2` would be
-            // pointers during const evaluation have no integral address, only an abstract one
-            Rvalue::Cast(CastKind::Misc, ref operand, cast_ty)
-                if self.const_context && self.tcx.features().const_raw_ptr_to_usize_cast =>
-            {
-                let operand_ty = operand.ty(self.body, self.tcx);
-                let cast_in = CastTy::from_ty(operand_ty).expect("bad input type for cast");
-                let cast_out = CastTy::from_ty(cast_ty).expect("bad output type for cast");
-                match (cast_in, cast_out) {
-                    (CastTy::Ptr(_) | CastTy::FnPtr, CastTy::Int(_)) => {
-                        self.require_unsafe(
-                            UnsafetyViolationKind::General,
-                            UnsafetyViolationDetails::CastOfPointerToInt,
-                        );
-                    }
-                    _ => {}
-                }
-            }
             _ => {}
         }
         self.super_rvalue(rvalue, location);
@@ -469,13 +446,7 @@ fn unsafety_check_result<'tcx>(
 
     let param_env = tcx.param_env(def.did);
 
-    let id = tcx.hir().local_def_id_to_hir_id(def.did);
-    let const_context = match tcx.hir().body_owner_kind(id) {
-        hir::BodyOwnerKind::Closure => false,
-        hir::BodyOwnerKind::Fn => tcx.is_const_fn_raw(def.did.to_def_id()),
-        hir::BodyOwnerKind::Const | hir::BodyOwnerKind::Static(_) => true,
-    };
-    let mut checker = UnsafetyChecker::new(const_context, body, def.did, tcx, param_env);
+    let mut checker = UnsafetyChecker::new(body, def.did, tcx, param_env);
     checker.visit_body(&body);
 
     check_unused_unsafe(tcx, def.did, &checker.used_unsafe, &mut checker.inherited_blocks);
diff --git a/compiler/rustc_mir/src/transform/inline.rs b/compiler/rustc_mir/src/transform/inline.rs
index c8791ec227c..703ac39dc30 100644
--- a/compiler/rustc_mir/src/transform/inline.rs
+++ b/compiler/rustc_mir/src/transform/inline.rs
@@ -284,7 +284,7 @@ impl Inliner<'tcx> {
         &self,
         callsite: &CallSite<'tcx>,
         callee_attrs: &CodegenFnAttrs,
-    ) -> Result<(), &'satic str> {
+    ) -> Result<(), &'static str> {
         if let InlineAttr::Never = callee_attrs.inline {
             return Err("never inline hint");
         }
diff --git a/compiler/rustc_mir_build/src/check_unsafety.rs b/compiler/rustc_mir_build/src/check_unsafety.rs
index c3af98fae9d..38111527a4e 100644
--- a/compiler/rustc_mir_build/src/check_unsafety.rs
+++ b/compiler/rustc_mir_build/src/check_unsafety.rs
@@ -25,7 +25,6 @@ struct UnsafetyVisitor<'a, 'tcx> {
     /// The `#[target_feature]` attributes of the body. Used for checking
     /// calls to functions with `#[target_feature]` (RFC 2396).
     body_target_features: &'tcx Vec<Symbol>,
-    is_const: bool,
     in_possible_lhs_union_assign: bool,
     in_union_destructure: bool,
 }
@@ -315,16 +314,6 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
                 (Bound::Unbounded, Bound::Unbounded) => {}
                 _ => self.requires_unsafe(expr.span, InitializingTypeWith),
             },
-            ExprKind::Cast { source } => {
-                let source = &self.thir[source];
-                if self.tcx.features().const_raw_ptr_to_usize_cast
-                    && self.is_const
-                    && (source.ty.is_unsafe_ptr() || source.ty.is_fn_ptr())
-                    && expr.ty.is_integral()
-                {
-                    self.requires_unsafe(expr.span, CastOfPointerToInt);
-                }
-            }
             ExprKind::Closure {
                 closure_id,
                 substs: _,
@@ -413,7 +402,6 @@ enum UnsafeOpKind {
     CallToUnsafeFunction,
     UseOfInlineAssembly,
     InitializingTypeWith,
-    CastOfPointerToInt,
     UseOfMutableStatic,
     UseOfExternStatic,
     DerefOfRawPointer,
@@ -446,9 +434,6 @@ impl UnsafeOpKind {
                 "initializing a layout restricted type's field with a value outside the valid \
                  range is undefined behavior",
             ),
-            CastOfPointerToInt => {
-                ("cast of pointer to int", "casting pointers to integers in constants")
-            }
             UseOfMutableStatic => (
                 "use of mutable static",
                 "mutable statics can be mutated by multiple threads: aliasing violations or data \
@@ -526,11 +511,6 @@ pub fn check_unsafety<'tcx>(tcx: TyCtxt<'tcx>, def: ty::WithOptConstParam<LocalD
     let body_target_features = &tcx.codegen_fn_attrs(def.did).target_features;
     let safety_context =
         if body_unsafety.is_unsafe() { SafetyContext::UnsafeFn } else { SafetyContext::Safe };
-    let is_const = match tcx.hir().body_owner_kind(hir_id) {
-        hir::BodyOwnerKind::Closure => false,
-        hir::BodyOwnerKind::Fn => tcx.is_const_fn_raw(def.did.to_def_id()),
-        hir::BodyOwnerKind::Const | hir::BodyOwnerKind::Static(_) => true,
-    };
     let mut visitor = UnsafetyVisitor {
         tcx,
         thir,
@@ -538,7 +518,6 @@ pub fn check_unsafety<'tcx>(tcx: TyCtxt<'tcx>, def: ty::WithOptConstParam<LocalD
         hir_context: hir_id,
         body_unsafety,
         body_target_features,
-        is_const,
         in_possible_lhs_union_assign: false,
         in_union_destructure: false,
     };
diff --git a/library/std/src/thread/mod.rs b/library/std/src/thread/mod.rs
index da2d1160493..9f7e6b95dfb 100644
--- a/library/std/src/thread/mod.rs
+++ b/library/std/src/thread/mod.rs
@@ -999,11 +999,12 @@ impl ThreadId {
         static mut COUNTER: u64 = 1;
 
         unsafe {
-            let _guard = GUARD.lock();
+            let guard = GUARD.lock();
 
             // If we somehow use up all our bits, panic so that we're not
             // covering up subtle bugs of IDs being reused.
             if COUNTER == u64::MAX {
+                drop(guard); // in case the panic handler ends up calling `ThreadId::new()`, avoid reentrant lock acquire.
                 panic!("failed to generate unique thread ID: bitspace exhausted");
             }
 
diff --git a/src/test/ui/attributes/nonterminal-expansion.rs b/src/test/ui/attributes/nonterminal-expansion.rs
index d663431d683..97bf225f0cc 100644
--- a/src/test/ui/attributes/nonterminal-expansion.rs
+++ b/src/test/ui/attributes/nonterminal-expansion.rs
@@ -2,7 +2,9 @@
 
 macro_rules! pass_nonterminal {
     ($n:expr) => {
-        #[repr(align($n))] //~ ERROR expected unsuffixed literal or identifier, found `n!()`
+        #[repr(align($n))]
+        //~^ ERROR expected unsuffixed literal or identifier, found `n!()`
+        //~| ERROR incorrect `repr(align)` attribute format
         struct S;
     };
 }
diff --git a/src/test/ui/attributes/nonterminal-expansion.stderr b/src/test/ui/attributes/nonterminal-expansion.stderr
index 4124f8cea8e..9bf36f3c58e 100644
--- a/src/test/ui/attributes/nonterminal-expansion.stderr
+++ b/src/test/ui/attributes/nonterminal-expansion.stderr
@@ -9,5 +9,17 @@ LL | pass_nonterminal!(n!());
    |
    = note: this error originates in the macro `pass_nonterminal` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: aborting due to previous error
+error[E0693]: incorrect `repr(align)` attribute format: `align` takes exactly one argument in parentheses
+  --> $DIR/nonterminal-expansion.rs:5:16
+   |
+LL |         #[repr(align($n))]
+   |                ^^^^^^^^^
+...
+LL | pass_nonterminal!(n!());
+   | ------------------------ in this macro invocation
+   |
+   = note: this error originates in the macro `pass_nonterminal` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 2 previous errors
 
+For more information about this error, try `rustc --explain E0693`.
diff --git a/src/test/ui/cast/cast-ptr-to-int-const.mir.stderr b/src/test/ui/cast/cast-ptr-to-int-const.mir.stderr
deleted file mode 100644
index dcc9a243f0f..00000000000
--- a/src/test/ui/cast/cast-ptr-to-int-const.mir.stderr
+++ /dev/null
@@ -1,19 +0,0 @@
-error[E0133]: cast of pointer to int is unsafe and requires unsafe function or block
-  --> $DIR/cast-ptr-to-int-const.rs:10:9
-   |
-LL |         &Y as *const u32 as usize
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^ cast of pointer to int
-   |
-   = note: casting pointers to integers in constants
-
-error[E0133]: cast of pointer to int is unsafe and requires unsafe function or block
-  --> $DIR/cast-ptr-to-int-const.rs:17:5
-   |
-LL |     &0 as *const i32 as usize
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^ cast of pointer to int
-   |
-   = note: casting pointers to integers in constants
-
-error: aborting due to 2 previous errors
-
-For more information about this error, try `rustc --explain E0133`.
diff --git a/src/test/ui/cast/cast-ptr-to-int-const.rs b/src/test/ui/cast/cast-ptr-to-int-const.rs
deleted file mode 100644
index 01ea627679d..00000000000
--- a/src/test/ui/cast/cast-ptr-to-int-const.rs
+++ /dev/null
@@ -1,19 +0,0 @@
-// revisions: mir thir
-// [thir]compile-flags: -Z thir-unsafeck
-
-#![feature(const_raw_ptr_to_usize_cast)]
-
-fn main() {
-    const Y: u32 = 0;
-    // Cast in `const` without `unsafe` block
-    const SAFE: usize = {
-        &Y as *const u32 as usize
-        //~^ ERROR cast of pointer to int is unsafe and requires unsafe
-    };
-}
-
-// Cast in `const fn` without `unsafe` block
-const fn test() -> usize {
-    &0 as *const i32 as usize
-    //~^ ERROR cast of pointer to int is unsafe and requires unsafe
-}
diff --git a/src/test/ui/cast/cast-ptr-to-int-const.thir.stderr b/src/test/ui/cast/cast-ptr-to-int-const.thir.stderr
deleted file mode 100644
index dcc9a243f0f..00000000000
--- a/src/test/ui/cast/cast-ptr-to-int-const.thir.stderr
+++ /dev/null
@@ -1,19 +0,0 @@
-error[E0133]: cast of pointer to int is unsafe and requires unsafe function or block
-  --> $DIR/cast-ptr-to-int-const.rs:10:9
-   |
-LL |         &Y as *const u32 as usize
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^ cast of pointer to int
-   |
-   = note: casting pointers to integers in constants
-
-error[E0133]: cast of pointer to int is unsafe and requires unsafe function or block
-  --> $DIR/cast-ptr-to-int-const.rs:17:5
-   |
-LL |     &0 as *const i32 as usize
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^ cast of pointer to int
-   |
-   = note: casting pointers to integers in constants
-
-error: aborting due to 2 previous errors
-
-For more information about this error, try `rustc --explain E0133`.
diff --git a/src/test/ui/cast/feature-gate-const_raw_ptr_to_usize_cast.rs b/src/test/ui/cast/feature-gate-const_raw_ptr_to_usize_cast.rs
deleted file mode 100644
index 03e99eb7527..00000000000
--- a/src/test/ui/cast/feature-gate-const_raw_ptr_to_usize_cast.rs
+++ /dev/null
@@ -1,13 +0,0 @@
-fn main() {
-    const X: usize = unsafe {
-        main as usize //~ ERROR casting pointers to integers in constants is unstable
-    };
-    const Y: u32 = 0;
-    const Z: usize = unsafe {
-        &Y as *const u32 as usize //~ ERROR is unstable
-    };
-}
-
-const fn test() -> usize {
-    &0 as *const i32 as usize //~ ERROR is unstable
-}
diff --git a/src/test/ui/cast/feature-gate-const_raw_ptr_to_usize_cast.stderr b/src/test/ui/cast/feature-gate-const_raw_ptr_to_usize_cast.stderr
deleted file mode 100644
index 4a0b424e181..00000000000
--- a/src/test/ui/cast/feature-gate-const_raw_ptr_to_usize_cast.stderr
+++ /dev/null
@@ -1,30 +0,0 @@
-error[E0658]: casting pointers to integers in constants is unstable
-  --> $DIR/feature-gate-const_raw_ptr_to_usize_cast.rs:3:9
-   |
-LL |         main as usize
-   |         ^^^^^^^^^^^^^
-   |
-   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
-   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
-
-error[E0658]: casting pointers to integers in constants is unstable
-  --> $DIR/feature-gate-const_raw_ptr_to_usize_cast.rs:7:9
-   |
-LL |         &Y as *const u32 as usize
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
-   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
-
-error[E0658]: casting pointers to integers in constant functions is unstable
-  --> $DIR/feature-gate-const_raw_ptr_to_usize_cast.rs:12:5
-   |
-LL |     &0 as *const i32 as usize
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
-   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
-
-error: aborting due to 3 previous errors
-
-For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/const-ptr/ptr_to_usize_cast.rs b/src/test/ui/const-ptr/ptr_to_usize_cast.rs
deleted file mode 100644
index bf1e790b5dc..00000000000
--- a/src/test/ui/const-ptr/ptr_to_usize_cast.rs
+++ /dev/null
@@ -1,13 +0,0 @@
-#![feature(const_raw_ptr_to_usize_cast)]
-
-fn main() {
-    const OK: usize = unsafe { 0 as *const i32 as usize };
-
-    const _ERROR: usize = unsafe { &0 as *const i32 as usize };
-    //~^ ERROR [const_err]
-    //~| NOTE cannot cast pointer to integer because it was not created by cast from integer
-    //~| NOTE
-    //~| NOTE `#[deny(const_err)]` on by default
-    //~| WARN this was previously accepted by the compiler but is being phased out
-    //~| NOTE see issue #71800
-}
diff --git a/src/test/ui/const-ptr/ptr_to_usize_cast.stderr b/src/test/ui/const-ptr/ptr_to_usize_cast.stderr
deleted file mode 100644
index 48255860bb5..00000000000
--- a/src/test/ui/const-ptr/ptr_to_usize_cast.stderr
+++ /dev/null
@@ -1,14 +0,0 @@
-error: any use of this value will cause an error
-  --> $DIR/ptr_to_usize_cast.rs:6:36
-   |
-LL |     const _ERROR: usize = unsafe { &0 as *const i32 as usize };
-   |     -------------------------------^^^^^^^^^^^^^^^^^^^^^^^^^---
-   |                                    |
-   |                                    cannot cast pointer to integer because it was not created by cast from integer
-   |
-   = note: `#[deny(const_err)]` on by default
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
-
-error: aborting due to previous error
-
diff --git a/src/test/ui/consts/const-eval/const_raw_ptr_ops2.rs b/src/test/ui/consts/const-eval/const_raw_ptr_ops2.rs
index c6a623b2932..a177ed6b341 100644
--- a/src/test/ui/consts/const-eval/const_raw_ptr_ops2.rs
+++ b/src/test/ui/consts/const-eval/const_raw_ptr_ops2.rs
@@ -1,15 +1,11 @@
-#![feature(const_raw_ptr_to_usize_cast, const_raw_ptr_deref)]
+#![feature(const_raw_ptr_deref)]
 
 fn main() {}
 
-// unconst and fine
-const Y: usize = unsafe { 42usize as *const i32 as usize + 1 };
-// unconst and bad, will thus error in miri
-const Y2: usize = unsafe { &1 as *const i32 as usize + 1 }; //~ ERROR any use of this
-//~| WARN this was previously accepted by the compiler but is being phased out
-// unconst and fine
+// fine
 const Z: i32 = unsafe { *(&1 as *const i32) };
-// unconst and bad, will thus error in miri
+
+// bad, will thus error in miri
 const Z2: i32 = unsafe { *(42 as *const i32) }; //~ ERROR any use of this value will cause
 //~| WARN this was previously accepted by the compiler but is being phased out
 const Z3: i32 = unsafe { *(44 as *const i32) }; //~ ERROR any use of this value will cause
diff --git a/src/test/ui/consts/const-eval/const_raw_ptr_ops2.stderr b/src/test/ui/consts/const-eval/const_raw_ptr_ops2.stderr
index df8b33a0898..de54ea3b9fb 100644
--- a/src/test/ui/consts/const-eval/const_raw_ptr_ops2.stderr
+++ b/src/test/ui/consts/const-eval/const_raw_ptr_ops2.stderr
@@ -1,28 +1,17 @@
 error: any use of this value will cause an error
-  --> $DIR/const_raw_ptr_ops2.rs:8:28
-   |
-LL | const Y2: usize = unsafe { &1 as *const i32 as usize + 1 };
-   | ---------------------------^^^^^^^^^^^^^^^^^^^^^^^^^-------
-   |                            |
-   |                            cannot cast pointer to integer because it was not created by cast from integer
-   |
-   = note: `#[deny(const_err)]` on by default
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
-
-error: any use of this value will cause an error
-  --> $DIR/const_raw_ptr_ops2.rs:13:26
+  --> $DIR/const_raw_ptr_ops2.rs:9:26
    |
 LL | const Z2: i32 = unsafe { *(42 as *const i32) };
    | -------------------------^^^^^^^^^^^^^^^^^^^---
    |                          |
    |                          unable to turn bytes into a pointer
    |
+   = note: `#[deny(const_err)]` on by default
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
 
 error: any use of this value will cause an error
-  --> $DIR/const_raw_ptr_ops2.rs:15:26
+  --> $DIR/const_raw_ptr_ops2.rs:11:26
    |
 LL | const Z3: i32 = unsafe { *(44 as *const i32) };
    | -------------------------^^^^^^^^^^^^^^^^^^^---
@@ -32,5 +21,5 @@ LL | const Z3: i32 = unsafe { *(44 as *const i32) };
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/consts/const-eval/issue-52442.rs b/src/test/ui/consts/const-eval/issue-52442.rs
deleted file mode 100644
index 159b48d42b6..00000000000
--- a/src/test/ui/consts/const-eval/issue-52442.rs
+++ /dev/null
@@ -1,4 +0,0 @@
-fn main() {
-    [();  { &loop { break } as *const _ as usize } ];
-    //~^ ERROR casting pointers to integers in constants is unstable
-}
diff --git a/src/test/ui/consts/const-eval/issue-52442.stderr b/src/test/ui/consts/const-eval/issue-52442.stderr
deleted file mode 100644
index 2a8f34279c3..00000000000
--- a/src/test/ui/consts/const-eval/issue-52442.stderr
+++ /dev/null
@@ -1,12 +0,0 @@
-error[E0658]: casting pointers to integers in constants is unstable
-  --> $DIR/issue-52442.rs:2:13
-   |
-LL |     [();  { &loop { break } as *const _ as usize } ];
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
-   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/consts/const-eval/match-test-ptr-null.rs b/src/test/ui/consts/const-eval/match-test-ptr-null.rs
index d980eb92a24..4af97b54879 100644
--- a/src/test/ui/consts/const-eval/match-test-ptr-null.rs
+++ b/src/test/ui/consts/const-eval/match-test-ptr-null.rs
@@ -4,7 +4,7 @@ fn main() {
     // bytes.
     let _: [u8; 0] = [4; {
         match &1 as *const i32 as usize {
-            //~^ ERROR casting pointers to integers in constants
+            //~^ ERROR pointers cannot be cast to integers during const eval
             0 => 42,
             n => n,
         }
diff --git a/src/test/ui/consts/const-eval/match-test-ptr-null.stderr b/src/test/ui/consts/const-eval/match-test-ptr-null.stderr
index 22d6bb16944..4e55b36da73 100644
--- a/src/test/ui/consts/const-eval/match-test-ptr-null.stderr
+++ b/src/test/ui/consts/const-eval/match-test-ptr-null.stderr
@@ -1,12 +1,11 @@
-error[E0658]: casting pointers to integers in constants is unstable
+error: pointers cannot be cast to integers during const eval.
   --> $DIR/match-test-ptr-null.rs:6:15
    |
 LL |         match &1 as *const i32 as usize {
    |               ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
-   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
+   = note: at compile-time, pointers do not have an integer value
+   = note: avoiding this restriction via `transmute`, `union`, or raw pointers leads to compile-time undefined behavior
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/consts/const-eval/promoted_raw_ptr_ops.rs b/src/test/ui/consts/const-eval/promoted_raw_ptr_ops.rs
index d724fe3060b..c7d84303fe5 100644
--- a/src/test/ui/consts/const-eval/promoted_raw_ptr_ops.rs
+++ b/src/test/ui/consts/const-eval/promoted_raw_ptr_ops.rs
@@ -1,4 +1,4 @@
-#![feature(const_raw_ptr_to_usize_cast, const_raw_ptr_deref)]
+#![feature(const_raw_ptr_deref)]
 
 fn main() {
     let x: &'static bool = &(42 as *const i32 == 43 as *const i32);
diff --git a/src/test/ui/consts/const-extern-fn/const-extern-fn-min-const-fn.rs b/src/test/ui/consts/const-extern-fn/const-extern-fn-min-const-fn.rs
index 76380ebcb65..46748673067 100644
--- a/src/test/ui/consts/const-extern-fn/const-extern-fn-min-const-fn.rs
+++ b/src/test/ui/consts/const-extern-fn/const-extern-fn-min-const-fn.rs
@@ -7,7 +7,7 @@ const unsafe extern "C" fn closure() -> fn() { || {} }
 const unsafe extern "C" fn use_float() { 1.0 + 1.0; }
 //~^ ERROR floating point arithmetic
 const extern "C" fn ptr_cast(val: *const u8) { val as usize; }
-//~^ ERROR casting pointers to integers
+//~^ ERROR pointers cannot be cast to integers
 
 
 fn main() {}
diff --git a/src/test/ui/consts/const-extern-fn/const-extern-fn-min-const-fn.stderr b/src/test/ui/consts/const-extern-fn/const-extern-fn-min-const-fn.stderr
index 80d234b0e88..2e52bae2b67 100644
--- a/src/test/ui/consts/const-extern-fn/const-extern-fn-min-const-fn.stderr
+++ b/src/test/ui/consts/const-extern-fn/const-extern-fn-min-const-fn.stderr
@@ -25,14 +25,14 @@ LL | const unsafe extern "C" fn use_float() { 1.0 + 1.0; }
    = note: see issue #57241 <https://github.com/rust-lang/rust/issues/57241> for more information
    = help: add `#![feature(const_fn_floating_point_arithmetic)]` to the crate attributes to enable
 
-error[E0658]: casting pointers to integers in constant functions is unstable
+error: pointers cannot be cast to integers during const eval.
   --> $DIR/const-extern-fn-min-const-fn.rs:9:48
    |
 LL | const extern "C" fn ptr_cast(val: *const u8) { val as usize; }
    |                                                ^^^^^^^^^^^^
    |
-   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
-   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
+   = note: at compile-time, pointers do not have an integer value
+   = note: avoiding this restriction via `transmute`, `union`, or raw pointers leads to compile-time undefined behavior
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/consts/issue-17458.rs b/src/test/ui/consts/issue-17458.rs
index d56ffebad7d..44125a1c3df 100644
--- a/src/test/ui/consts/issue-17458.rs
+++ b/src/test/ui/consts/issue-17458.rs
@@ -1,5 +1,5 @@
 static X: usize = unsafe { core::ptr::null::<usize>() as usize };
-//~^ ERROR: casting pointers to integers in statics is unstable
+//~^ ERROR: pointers cannot be cast to integers during const eval
 
 fn main() {
     assert_eq!(X, 0);
diff --git a/src/test/ui/consts/issue-17458.stderr b/src/test/ui/consts/issue-17458.stderr
index 68e86ea21bd..aab7d798db2 100644
--- a/src/test/ui/consts/issue-17458.stderr
+++ b/src/test/ui/consts/issue-17458.stderr
@@ -1,12 +1,11 @@
-error[E0658]: casting pointers to integers in statics is unstable
+error: pointers cannot be cast to integers during const eval.
   --> $DIR/issue-17458.rs:1:28
    |
 LL | static X: usize = unsafe { core::ptr::null::<usize>() as usize };
    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
-   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
+   = note: at compile-time, pointers do not have an integer value
+   = note: avoiding this restriction via `transmute`, `union`, or raw pointers leads to compile-time undefined behavior
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/consts/issue-51559.rs b/src/test/ui/consts/issue-51559.rs
deleted file mode 100644
index cc644404f7d..00000000000
--- a/src/test/ui/consts/issue-51559.rs
+++ /dev/null
@@ -1,8 +0,0 @@
-#![feature(const_raw_ptr_to_usize_cast)]
-
-const BAR: *mut () = ((|| 3) as fn() -> i32) as *mut ();
-pub const FOO: usize = unsafe { BAR as usize };
-//~^ ERROR any use of this value will cause an error
-//~| WARN this was previously accepted by the compiler but is being phased out
-
-fn main() {}
diff --git a/src/test/ui/consts/issue-51559.stderr b/src/test/ui/consts/issue-51559.stderr
deleted file mode 100644
index d571eb54963..00000000000
--- a/src/test/ui/consts/issue-51559.stderr
+++ /dev/null
@@ -1,14 +0,0 @@
-error: any use of this value will cause an error
-  --> $DIR/issue-51559.rs:4:33
-   |
-LL | pub const FOO: usize = unsafe { BAR as usize };
-   | --------------------------------^^^^^^^^^^^^---
-   |                                 |
-   |                                 cannot cast pointer to integer because it was not created by cast from integer
-   |
-   = note: `#[deny(const_err)]` on by default
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
-
-error: aborting due to previous error
-
diff --git a/src/test/ui/consts/issue-52023-array-size-pointer-cast.rs b/src/test/ui/consts/issue-52023-array-size-pointer-cast.rs
index cc756ce815f..2249d9879f5 100644
--- a/src/test/ui/consts/issue-52023-array-size-pointer-cast.rs
+++ b/src/test/ui/consts/issue-52023-array-size-pointer-cast.rs
@@ -1,3 +1,3 @@
 fn main() {
-    let _ = [0; (&0 as *const i32) as usize]; //~ ERROR casting pointers to integers in constants
+    let _ = [0; (&0 as *const i32) as usize]; //~ ERROR pointers cannot be cast to integers during const eval
 }
diff --git a/src/test/ui/consts/issue-52023-array-size-pointer-cast.stderr b/src/test/ui/consts/issue-52023-array-size-pointer-cast.stderr
index 68b5cbd9bd7..363c7b2c8e4 100644
--- a/src/test/ui/consts/issue-52023-array-size-pointer-cast.stderr
+++ b/src/test/ui/consts/issue-52023-array-size-pointer-cast.stderr
@@ -1,12 +1,11 @@
-error[E0658]: casting pointers to integers in constants is unstable
+error: pointers cannot be cast to integers during const eval.
   --> $DIR/issue-52023-array-size-pointer-cast.rs:2:17
    |
 LL |     let _ = [0; (&0 as *const i32) as usize];
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
-   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
+   = note: at compile-time, pointers do not have an integer value
+   = note: avoiding this restriction via `transmute`, `union`, or raw pointers leads to compile-time undefined behavior
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/consts/issue-52432.rs b/src/test/ui/consts/issue-52432.rs
deleted file mode 100644
index d719bf1b971..00000000000
--- a/src/test/ui/consts/issue-52432.rs
+++ /dev/null
@@ -1,10 +0,0 @@
-#![feature(const_raw_ptr_to_usize_cast)]
-
-fn main() {
-    [(); &(static |x| {}) as *const _ as usize];
-    //~^ ERROR: closures cannot be static
-    //~| ERROR: type annotations needed
-    [(); &(static || {}) as *const _ as usize];
-    //~^ ERROR: closures cannot be static
-    //~| ERROR evaluation of constant value failed
-}
diff --git a/src/test/ui/consts/issue-52432.stderr b/src/test/ui/consts/issue-52432.stderr
deleted file mode 100644
index 29998950552..00000000000
--- a/src/test/ui/consts/issue-52432.stderr
+++ /dev/null
@@ -1,28 +0,0 @@
-error[E0697]: closures cannot be static
-  --> $DIR/issue-52432.rs:4:12
-   |
-LL |     [(); &(static |x| {}) as *const _ as usize];
-   |            ^^^^^^^^^^
-
-error[E0697]: closures cannot be static
-  --> $DIR/issue-52432.rs:7:12
-   |
-LL |     [(); &(static || {}) as *const _ as usize];
-   |            ^^^^^^^^^
-
-error[E0282]: type annotations needed
-  --> $DIR/issue-52432.rs:4:20
-   |
-LL |     [(); &(static |x| {}) as *const _ as usize];
-   |                    ^ consider giving this closure parameter a type
-
-error[E0080]: evaluation of constant value failed
-  --> $DIR/issue-52432.rs:7:10
-   |
-LL |     [(); &(static || {}) as *const _ as usize];
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot cast pointer to integer because it was not created by cast from integer
-
-error: aborting due to 4 previous errors
-
-Some errors have detailed explanations: E0080, E0282, E0697.
-For more information about an error, try `rustc --explain E0080`.
diff --git a/src/test/ui/consts/min_const_fn/min_const_fn.rs b/src/test/ui/consts/min_const_fn/min_const_fn.rs
index b7904e6841b..bb525d57197 100644
--- a/src/test/ui/consts/min_const_fn/min_const_fn.rs
+++ b/src/test/ui/consts/min_const_fn/min_const_fn.rs
@@ -90,13 +90,13 @@ static BAR: u32 = 42;
 const fn foo25() -> u32 { BAR } //~ ERROR cannot refer to statics
 const fn foo26() -> &'static u32 { &BAR } //~ ERROR cannot refer to statics
 const fn foo30(x: *const u32) -> usize { x as usize }
-//~^ ERROR casting pointers to integers
+//~^ ERROR pointers cannot be cast to integers
 const fn foo30_with_unsafe(x: *const u32) -> usize { unsafe { x as usize } }
-//~^ ERROR casting pointers to integers
+//~^ ERROR pointers cannot be cast to integers
 const fn foo30_2(x: *mut u32) -> usize { x as usize }
-//~^ ERROR casting pointers to integers
+//~^ ERROR pointers cannot be cast to integers
 const fn foo30_2_with_unsafe(x: *mut u32) -> usize { unsafe { x as usize } }
-//~^ ERROR casting pointers to integers
+//~^ ERROR pointers cannot be cast to integers
 const fn foo30_6() -> bool { let x = true; x }
 const fn inc(x: &mut i32) { *x += 1 }
 //~^ ERROR mutable references
diff --git a/src/test/ui/consts/min_const_fn/min_const_fn.stderr b/src/test/ui/consts/min_const_fn/min_const_fn.stderr
index d31d4121936..fcbf39d3869 100644
--- a/src/test/ui/consts/min_const_fn/min_const_fn.stderr
+++ b/src/test/ui/consts/min_const_fn/min_const_fn.stderr
@@ -164,41 +164,41 @@ LL | const fn foo26() -> &'static u32 { &BAR }
    |
    = help: consider extracting the value of the `static` to a `const`, and referring to that
 
-error[E0658]: casting pointers to integers in constant functions is unstable
+error: pointers cannot be cast to integers during const eval.
   --> $DIR/min_const_fn.rs:92:42
    |
 LL | const fn foo30(x: *const u32) -> usize { x as usize }
    |                                          ^^^^^^^^^^
    |
-   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
-   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
+   = note: at compile-time, pointers do not have an integer value
+   = note: avoiding this restriction via `transmute`, `union`, or raw pointers leads to compile-time undefined behavior
 
-error[E0658]: casting pointers to integers in constant functions is unstable
+error: pointers cannot be cast to integers during const eval.
   --> $DIR/min_const_fn.rs:94:63
    |
 LL | const fn foo30_with_unsafe(x: *const u32) -> usize { unsafe { x as usize } }
    |                                                               ^^^^^^^^^^
    |
-   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
-   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
+   = note: at compile-time, pointers do not have an integer value
+   = note: avoiding this restriction via `transmute`, `union`, or raw pointers leads to compile-time undefined behavior
 
-error[E0658]: casting pointers to integers in constant functions is unstable
+error: pointers cannot be cast to integers during const eval.
   --> $DIR/min_const_fn.rs:96:42
    |
 LL | const fn foo30_2(x: *mut u32) -> usize { x as usize }
    |                                          ^^^^^^^^^^
    |
-   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
-   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
+   = note: at compile-time, pointers do not have an integer value
+   = note: avoiding this restriction via `transmute`, `union`, or raw pointers leads to compile-time undefined behavior
 
-error[E0658]: casting pointers to integers in constant functions is unstable
+error: pointers cannot be cast to integers during const eval.
   --> $DIR/min_const_fn.rs:98:63
    |
 LL | const fn foo30_2_with_unsafe(x: *mut u32) -> usize { unsafe { x as usize } }
    |                                                               ^^^^^^^^^^
    |
-   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
-   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
+   = note: at compile-time, pointers do not have an integer value
+   = note: avoiding this restriction via `transmute`, `union`, or raw pointers leads to compile-time undefined behavior
 
 error[E0658]: mutable references are not allowed in constant functions
   --> $DIR/min_const_fn.rs:101:14
diff --git a/src/test/ui/issues/issue-18294.rs b/src/test/ui/issues/issue-18294.rs
index 1c2229fb9ea..77355f0d7c9 100644
--- a/src/test/ui/issues/issue-18294.rs
+++ b/src/test/ui/issues/issue-18294.rs
@@ -1,5 +1,5 @@
 fn main() {
     const X: u32 = 1;
-    const Y: usize = unsafe { &X as *const u32 as usize }; //~ ERROR is unstable
+    const Y: usize = unsafe { &X as *const u32 as usize }; //~ ERROR pointers cannot be cast to integers
     println!("{}", Y);
 }
diff --git a/src/test/ui/issues/issue-18294.stderr b/src/test/ui/issues/issue-18294.stderr
index 52df558bfce..432e9a65187 100644
--- a/src/test/ui/issues/issue-18294.stderr
+++ b/src/test/ui/issues/issue-18294.stderr
@@ -1,12 +1,11 @@
-error[E0658]: casting pointers to integers in constants is unstable
+error: pointers cannot be cast to integers during const eval.
   --> $DIR/issue-18294.rs:3:31
    |
 LL |     const Y: usize = unsafe { &X as *const u32 as usize };
    |                               ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
-   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
+   = note: at compile-time, pointers do not have an integer value
+   = note: avoiding this restriction via `transmute`, `union`, or raw pointers leads to compile-time undefined behavior
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/repr/issue-83921-ice.rs b/src/test/ui/repr/issue-83921-ice.rs
new file mode 100644
index 00000000000..70583eb9bd3
--- /dev/null
+++ b/src/test/ui/repr/issue-83921-ice.rs
@@ -0,0 +1,34 @@
+// Regression test for various ICEs inspired by
+// https://github.com/rust-lang/rust/issues/83921#issuecomment-814640734
+
+// compile-flags: -Zdeduplicate-diagnostics=yes
+
+#[repr(packed())]
+//~^ ERROR: incorrect `repr(packed)` attribute format
+struct S1;
+
+#[repr(align)]
+//~^ ERROR: invalid `repr(align)` attribute
+struct S2;
+
+#[repr(align(2, 4))]
+//~^ ERROR: incorrect `repr(align)` attribute format
+struct S3;
+
+#[repr(align())]
+//~^ ERROR: incorrect `repr(align)` attribute format
+struct S4;
+
+#[repr(i8())]
+//~^ ERROR: invalid representation hint
+enum E1 { A, B }
+
+#[repr(u32(42))]
+//~^ ERROR: invalid representation hint
+enum E2 { A, B }
+
+#[repr(i64 = 2)]
+//~^ ERROR: invalid representation hint
+enum E3 { A, B }
+
+fn main() {}
diff --git a/src/test/ui/repr/issue-83921-ice.stderr b/src/test/ui/repr/issue-83921-ice.stderr
new file mode 100644
index 00000000000..32c450410ea
--- /dev/null
+++ b/src/test/ui/repr/issue-83921-ice.stderr
@@ -0,0 +1,46 @@
+error[E0552]: incorrect `repr(packed)` attribute format: `packed` takes exactly one parenthesized argument, or no parentheses at all
+  --> $DIR/issue-83921-ice.rs:6:8
+   |
+LL | #[repr(packed())]
+   |        ^^^^^^^^
+
+error[E0589]: invalid `repr(align)` attribute: `align` needs an argument
+  --> $DIR/issue-83921-ice.rs:10:8
+   |
+LL | #[repr(align)]
+   |        ^^^^^ help: supply an argument here: `align(...)`
+
+error[E0693]: incorrect `repr(align)` attribute format: `align` takes exactly one argument in parentheses
+  --> $DIR/issue-83921-ice.rs:14:8
+   |
+LL | #[repr(align(2, 4))]
+   |        ^^^^^^^^^^^
+
+error[E0693]: incorrect `repr(align)` attribute format: `align` takes exactly one argument in parentheses
+  --> $DIR/issue-83921-ice.rs:18:8
+   |
+LL | #[repr(align())]
+   |        ^^^^^^^
+
+error[E0552]: invalid representation hint: `i8` does not take a parenthesized argument list
+  --> $DIR/issue-83921-ice.rs:22:8
+   |
+LL | #[repr(i8())]
+   |        ^^^^
+
+error[E0552]: invalid representation hint: `u32` does not take a parenthesized argument list
+  --> $DIR/issue-83921-ice.rs:26:8
+   |
+LL | #[repr(u32(42))]
+   |        ^^^^^^^
+
+error[E0552]: invalid representation hint: `i64` does not take a value
+  --> $DIR/issue-83921-ice.rs:30:8
+   |
+LL | #[repr(i64 = 2)]
+   |        ^^^^^^^
+
+error: aborting due to 7 previous errors
+
+Some errors have detailed explanations: E0552, E0589, E0693.
+For more information about an error, try `rustc --explain E0552`.
diff --git a/src/test/ui/repr/issue-83921-pretty.normal.stderr b/src/test/ui/repr/issue-83921-pretty.normal.stderr
new file mode 100644
index 00000000000..6b7e831ed2f
--- /dev/null
+++ b/src/test/ui/repr/issue-83921-pretty.normal.stderr
@@ -0,0 +1,9 @@
+error[E0565]: meta item in `repr` must be an identifier
+  --> $DIR/issue-83921-pretty.rs:10:8
+   |
+LL | #[repr("C")]
+   |        ^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0565`.
diff --git a/src/test/ui/repr/issue-83921-pretty.pretty.stdout b/src/test/ui/repr/issue-83921-pretty.pretty.stdout
new file mode 100644
index 00000000000..dad3641f0f5
--- /dev/null
+++ b/src/test/ui/repr/issue-83921-pretty.pretty.stdout
@@ -0,0 +1,19 @@
+#![feature(prelude_import)]
+#![no_std]
+#[prelude_import]
+use ::std::prelude::rust_2015::*;
+#[macro_use]
+extern crate std;
+// Regression test for #83921. A `delay_span_bug()` call was issued, but the
+// error was never reported because the pass responsible for detecting and
+// reporting the error does not run in certain modes of pretty-printing.
+
+// Make sure the error is reported if we do not just pretty-print:
+// revisions: pretty normal
+// [pretty]compile-flags: -Zunpretty=everybody_loops
+// [pretty]check-pass
+#[repr("C")]
+struct A {
+}
+
+fn main() { loop { } }
diff --git a/src/test/ui/repr/issue-83921-pretty.rs b/src/test/ui/repr/issue-83921-pretty.rs
new file mode 100644
index 00000000000..d5d36470f11
--- /dev/null
+++ b/src/test/ui/repr/issue-83921-pretty.rs
@@ -0,0 +1,14 @@
+// Regression test for #83921. A `delay_span_bug()` call was issued, but the
+// error was never reported because the pass responsible for detecting and
+// reporting the error does not run in certain modes of pretty-printing.
+
+// Make sure the error is reported if we do not just pretty-print:
+// revisions: pretty normal
+// [pretty]compile-flags: -Zunpretty=everybody_loops
+// [pretty]check-pass
+
+#[repr("C")]
+//[normal]~^ ERROR: meta item in `repr` must be an identifier [E0565]
+struct A {}
+
+fn main() {}