Auto merge of #129521 - matthiaskrgr:rollup-uigv77m, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - #128596 (stabilize const_fn_floating_point_arithmetic)
 - #129199 (make writes_through_immutable_pointer a hard error)
 - #129246 (Retroactively feature gate `ConstArgKind::Path`)
 - #129290 (Pin `cc` to 1.0.105)
 - #129323 (Implement `ptr::fn_addr_eq`)
 - #129500 (remove invalid `TyCompat` relation for effects)
 - #129501 (panicking: improve hint for Miri's RUST_BACKTRACE behavior)
 - #129505 (interpret: ImmTy: tighten sanity checks in offset logic)
 - #129510 (Fix `elided_named_lifetimes` in code)

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

6 files changed, 37 insertions, 68 deletions

diff --git a/compiler/rustc_const_eval/src/check_consts/check.rs b/compiler/rustc_const_eval/src/check_consts/check.rs
index 86a5afa65ba..c80b3e673b0 100644
--- a/compiler/rustc_const_eval/src/check_consts/check.rs
+++ b/compiler/rustc_const_eval/src/check_consts/check.rs
@@ -575,10 +575,8 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
 
             Rvalue::UnaryOp(_, operand) => {
                 let ty = operand.ty(self.body, self.tcx);
-                if is_int_bool_or_char(ty) {
-                    // Int, bool, and char operations are fine.
-                } else if ty.is_floating_point() {
-                    self.check_op(ops::FloatingPointOp);
+                if is_int_bool_float_or_char(ty) {
+                    // Int, bool, float, and char operations are fine.
                 } else {
                     span_bug!(self.span, "non-primitive type in `Rvalue::UnaryOp`: {:?}", ty);
                 }
@@ -588,8 +586,8 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                 let lhs_ty = lhs.ty(self.body, self.tcx);
                 let rhs_ty = rhs.ty(self.body, self.tcx);
 
-                if is_int_bool_or_char(lhs_ty) && is_int_bool_or_char(rhs_ty) {
-                    // Int, bool, and char operations are fine.
+                if is_int_bool_float_or_char(lhs_ty) && is_int_bool_float_or_char(rhs_ty) {
+                    // Int, bool, float, and char operations are fine.
                 } else if lhs_ty.is_fn_ptr() || lhs_ty.is_unsafe_ptr() {
                     assert_matches!(
                         op,
@@ -603,8 +601,6 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                     );
 
                     self.check_op(ops::RawPtrComparison);
-                } else if lhs_ty.is_floating_point() || rhs_ty.is_floating_point() {
-                    self.check_op(ops::FloatingPointOp);
                 } else {
                     span_bug!(
                         self.span,
@@ -1009,8 +1005,8 @@ fn place_as_reborrow<'tcx>(
     }
 }
 
-fn is_int_bool_or_char(ty: Ty<'_>) -> bool {
-    ty.is_bool() || ty.is_integral() || ty.is_char()
+fn is_int_bool_float_or_char(ty: Ty<'_>) -> bool {
+    ty.is_bool() || ty.is_integral() || ty.is_char() || ty.is_floating_point()
 }
 
 fn emit_unstable_in_stable_error(ccx: &ConstCx<'_, '_>, span: Span, gate: Symbol) {
diff --git a/compiler/rustc_const_eval/src/check_consts/ops.rs b/compiler/rustc_const_eval/src/check_consts/ops.rs
index 259114dbdc2..93fafa60557 100644
--- a/compiler/rustc_const_eval/src/check_consts/ops.rs
+++ b/compiler/rustc_const_eval/src/check_consts/ops.rs
@@ -55,28 +55,6 @@ pub trait NonConstOp<'tcx>: std::fmt::Debug {
     fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> Diag<'tcx>;
 }
 
-#[derive(Debug)]
-pub struct FloatingPointOp;
-impl<'tcx> NonConstOp<'tcx> for FloatingPointOp {
-    fn status_in_item(&self, ccx: &ConstCx<'_, 'tcx>) -> Status {
-        if ccx.const_kind() == hir::ConstContext::ConstFn {
-            Status::Unstable(sym::const_fn_floating_point_arithmetic)
-        } else {
-            Status::Allowed
-        }
-    }
-
-    #[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> Diag<'tcx> {
-        feature_err(
-            &ccx.tcx.sess,
-            sym::const_fn_floating_point_arithmetic,
-            span,
-            format!("floating point arithmetic is not allowed in {}s", ccx.const_kind()),
-        )
-    }
-}
-
 /// A function call where the callee is a pointer.
 #[derive(Debug)]
 pub struct FnCallIndirect;
@@ -440,22 +418,12 @@ impl<'tcx> NonConstOp<'tcx> for CellBorrow {
         DiagImportance::Secondary
     }
     fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> Diag<'tcx> {
-        // FIXME: Maybe a more elegant solution to this if else case
-        if let hir::ConstContext::Static(_) = ccx.const_kind() {
-            ccx.dcx().create_err(errors::InteriorMutableDataRefer {
-                span,
-                opt_help: true,
-                kind: ccx.const_kind(),
-                teach: ccx.tcx.sess.teach(E0492),
-            })
-        } else {
-            ccx.dcx().create_err(errors::InteriorMutableDataRefer {
-                span,
-                opt_help: false,
-                kind: ccx.const_kind(),
-                teach: ccx.tcx.sess.teach(E0492),
-            })
-        }
+        ccx.dcx().create_err(errors::InteriorMutableDataRefer {
+            span,
+            opt_help: matches!(ccx.const_kind(), hir::ConstContext::Static(_)),
+            kind: ccx.const_kind(),
+            teach: ccx.tcx.sess.teach(E0492),
+        })
     }
 }
 
diff --git a/compiler/rustc_const_eval/src/const_eval/error.rs b/compiler/rustc_const_eval/src/const_eval/error.rs
index 00bbd9337f7..25b32785b7d 100644
--- a/compiler/rustc_const_eval/src/const_eval/error.rs
+++ b/compiler/rustc_const_eval/src/const_eval/error.rs
@@ -22,6 +22,7 @@ pub enum ConstEvalErrKind {
     RecursiveStatic,
     AssertFailure(AssertKind<ConstInt>),
     Panic { msg: Symbol, line: u32, col: u32, file: Symbol },
+    WriteThroughImmutablePointer,
 }
 
 impl MachineStopType for ConstEvalErrKind {
@@ -35,12 +36,16 @@ impl MachineStopType for ConstEvalErrKind {
             Panic { .. } => const_eval_panic,
             RecursiveStatic => const_eval_recursive_static,
             AssertFailure(x) => x.diagnostic_message(),
+            WriteThroughImmutablePointer => const_eval_write_through_immutable_pointer,
         }
     }
     fn add_args(self: Box<Self>, adder: &mut dyn FnMut(DiagArgName, DiagArgValue)) {
         use ConstEvalErrKind::*;
         match *self {
-            RecursiveStatic | ConstAccessesMutGlobal | ModifiedGlobal => {}
+            RecursiveStatic
+            | ConstAccessesMutGlobal
+            | ModifiedGlobal
+            | WriteThroughImmutablePointer => {}
             AssertFailure(kind) => kind.add_args(adder),
             Panic { msg, line, col, file } => {
                 adder("msg".into(), msg.into_diag_arg());
@@ -159,6 +164,7 @@ where
 
 /// Emit a lint from a const-eval situation, with a backtrace.
 // Even if this is unused, please don't remove it -- chances are we will need to emit a lint during const-eval again in the future!
+#[allow(unused)]
 pub(super) fn lint<'tcx, L>(
     tcx: TyCtxtAt<'tcx>,
     machine: &CompileTimeMachine<'tcx>,
diff --git a/compiler/rustc_const_eval/src/const_eval/machine.rs b/compiler/rustc_const_eval/src/const_eval/machine.rs
index c3d94ca0e59..9c1fef095f5 100644
--- a/compiler/rustc_const_eval/src/const_eval/machine.rs
+++ b/compiler/rustc_const_eval/src/const_eval/machine.rs
@@ -12,7 +12,6 @@ use rustc_middle::query::TyCtxtAt;
 use rustc_middle::ty::layout::{FnAbiOf, TyAndLayout};
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_middle::{bug, mir};
-use rustc_session::lint::builtin::WRITES_THROUGH_IMMUTABLE_POINTER;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
 use rustc_target::abi::{Align, Size};
@@ -732,8 +731,8 @@ impl<'tcx> interpret::Machine<'tcx> for CompileTimeMachine<'tcx> {
     }
 
     fn before_memory_write(
-        tcx: TyCtxtAt<'tcx>,
-        machine: &mut Self,
+        _tcx: TyCtxtAt<'tcx>,
+        _machine: &mut Self,
         _alloc_extra: &mut Self::AllocExtra,
         (_alloc_id, immutable): (AllocId, bool),
         range: AllocRange,
@@ -744,9 +743,7 @@ impl<'tcx> interpret::Machine<'tcx> for CompileTimeMachine<'tcx> {
         }
         // Reject writes through immutable pointers.
         if immutable {
-            super::lint(tcx, machine, WRITES_THROUGH_IMMUTABLE_POINTER, |frames| {
-                crate::errors::WriteThroughImmutablePointer { frames }
-            });
+            return Err(ConstEvalErrKind::WriteThroughImmutablePointer.into());
         }
         // Everything else is fine.
         Ok(())
diff --git a/compiler/rustc_const_eval/src/errors.rs b/compiler/rustc_const_eval/src/errors.rs
index 6075f3f84cd..0b366b43f95 100644
--- a/compiler/rustc_const_eval/src/errors.rs
+++ b/compiler/rustc_const_eval/src/errors.rs
@@ -407,13 +407,6 @@ pub struct ConstEvalError {
     pub frame_notes: Vec<FrameNote>,
 }
 
-#[derive(LintDiagnostic)]
-#[diag(const_eval_write_through_immutable_pointer)]
-pub struct WriteThroughImmutablePointer {
-    #[subdiagnostic]
-    pub frames: Vec<FrameNote>,
-}
-
 #[derive(Diagnostic)]
 #[diag(const_eval_nullary_intrinsic_fail)]
 pub struct NullaryIntrinsicError {
diff --git a/compiler/rustc_const_eval/src/interpret/operand.rs b/compiler/rustc_const_eval/src/interpret/operand.rs
index ad87d6953d3..9a8ccaa7cc5 100644
--- a/compiler/rustc_const_eval/src/interpret/operand.rs
+++ b/compiler/rustc_const_eval/src/interpret/operand.rs
@@ -319,6 +319,7 @@ impl<'tcx, Prov: Provenance> ImmTy<'tcx, Prov> {
             // some fieldless enum variants can have non-zero size but still `Aggregate` ABI... try
             // to detect those here and also give them no data
             _ if matches!(layout.abi, Abi::Aggregate { .. })
+                && matches!(layout.variants, abi::Variants::Single { .. })
                 && matches!(&layout.fields, abi::FieldsShape::Arbitrary { offsets, .. } if offsets.len() == 0) =>
             {
                 Immediate::Uninit
@@ -328,8 +329,9 @@ impl<'tcx, Prov: Provenance> ImmTy<'tcx, Prov> {
                 assert_eq!(offset.bytes(), 0);
                 assert!(
                     match (self.layout.abi, layout.abi) {
-                        (Abi::Scalar(..), Abi::Scalar(..)) => true,
-                        (Abi::ScalarPair(..), Abi::ScalarPair(..)) => true,
+                        (Abi::Scalar(l), Abi::Scalar(r)) => l.size(cx) == r.size(cx),
+                        (Abi::ScalarPair(l1, l2), Abi::ScalarPair(r1, r2)) =>
+                            l1.size(cx) == r1.size(cx) && l2.size(cx) == r2.size(cx),
                         _ => false,
                     },
                     "cannot project into {} immediate with equally-sized field {}\nouter ABI: {:#?}\nfield ABI: {:#?}",
@@ -344,16 +346,23 @@ impl<'tcx, Prov: Provenance> ImmTy<'tcx, Prov> {
             (Immediate::ScalarPair(a_val, b_val), Abi::ScalarPair(a, b)) => {
                 assert_matches!(layout.abi, Abi::Scalar(..));
                 Immediate::from(if offset.bytes() == 0 {
-                    debug_assert_eq!(layout.size, a.size(cx));
+                    // It is "okay" to transmute from `usize` to a pointer (GVN relies on that).
+                    // So only compare the size.
+                    assert_eq!(layout.size, a.size(cx));
                     a_val
                 } else {
-                    debug_assert_eq!(offset, a.size(cx).align_to(b.align(cx).abi));
-                    debug_assert_eq!(layout.size, b.size(cx));
+                    assert_eq!(offset, a.size(cx).align_to(b.align(cx).abi));
+                    assert_eq!(layout.size, b.size(cx));
                     b_val
                 })
             }
             // everything else is a bug
-            _ => bug!("invalid field access on immediate {}, layout {:#?}", self, self.layout),
+            _ => bug!(
+                "invalid field access on immediate {} at offset {}, original layout {:#?}",
+                self,
+                offset.bytes(),
+                self.layout
+            ),
         };
 
         ImmTy::from_immediate(inner_val, layout)