Rollup of 7 pull requests

compiler/rustc_const_eval/src/interpret/call.rs

@@ -272,8 +272,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         caller_args: &mut impl Iterator<
             Item = (&'x FnArg<'tcx, M::Provenance>, &'y ArgAbi<'tcx, Ty<'tcx>>),
         >,
-        callee_abi: &ArgAbi<'tcx, Ty<'tcx>>,
-        callee_arg_idx: usize,
+        callee_args_abis: &mut impl Iterator<Item = (usize, &'y ArgAbi<'tcx, Ty<'tcx>>)>,
         callee_arg: &mir::Place<'tcx>,
         callee_ty: Ty<'tcx>,
         already_live: bool,
@@ -282,15 +281,10 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         'tcx: 'x,
         'tcx: 'y,
     {
+        // Get next callee arg.
+        let (callee_arg_idx, callee_abi) = callee_args_abis.next().unwrap();
         assert_eq!(callee_ty, callee_abi.layout.ty);
-        if callee_abi.is_ignore() {
-            // This one is skipped. Still must be made live though!
-            if !already_live {
-                self.storage_live(callee_arg.as_local().unwrap())?;
-            }
-            return interp_ok(());
-        }
-        // Find next caller arg.
+        // Get next caller arg.
         let Some((caller_arg, caller_abi)) = caller_args.next() else {
             throw_ub_format!("calling a function with fewer arguments than it requires");
         };
@@ -348,6 +342,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         mut cont: ReturnContinuation,
     ) -> InterpResult<'tcx> {
         let _trace = enter_trace_span!(M, step::init_stack_frame, %instance, tracing_separate_thread = Empty);
+        let def_id = instance.def_id();
 
         // The first order of business is to figure out the callee signature.
         // However, that requires the list of variadic arguments.
@@ -423,10 +418,25 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
             "spread_arg: {:?}, locals: {:#?}",
             body.spread_arg,
             body.args_iter()
-                .map(|local| (local, self.layout_of_local(self.frame(), local, None).unwrap().ty,))
+                .map(|local| (local, self.layout_of_local(self.frame(), local, None).unwrap().ty))
                 .collect::<Vec<_>>()
         );
 
+        // Determine whether there is a special VaList argument. This is always the
+        // last argument, and since arguments start at index 1 that's `arg_count`.
+        let va_list_arg = callee_fn_abi.c_variadic.then(|| mir::Local::from_usize(body.arg_count));
+        // Determine whether this is a non-capturing closure. That's relevant as their first
+        // argument can be skipped (and that's the only kind of argument skipping we allow).
+        let is_non_capturing_closure =
+            (matches!(instance.def, ty::InstanceKind::ClosureOnceShim { .. })
+                || self.tcx.is_closure_like(def_id))
+                && {
+                    let arg = &callee_fn_abi.args[0];
+                    matches!(arg.layout.ty.kind(), ty::Closure (_def, closure_args) if {
+                        closure_args.as_closure().upvar_tys().is_empty()
+                    })
+                };
+
         // In principle, we have two iterators: Where the arguments come from, and where
         // they go to.
 
@@ -439,21 +449,13 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
             caller_fn_abi.args.len(),
             "mismatch between caller ABI and caller arguments",
         );
-        let mut caller_args = args
-            .iter()
-            .zip(caller_fn_abi.args.iter())
-            .filter(|arg_and_abi| !arg_and_abi.1.is_ignore());
+        let mut caller_args = args.iter().zip(caller_fn_abi.args.iter());
 
         // Now we have to spread them out across the callee's locals,
         // taking into account the `spread_arg`. If we could write
         // this is a single iterator (that handles `spread_arg`), then
-        // `pass_argument` would be the loop body. It takes care to
-        // not advance `caller_iter` for ignored arguments.
+        // `pass_argument` would be the loop body.
         let mut callee_args_abis = callee_fn_abi.args.iter().enumerate();
-        // Determine whether there is a special VaList argument. This is always the
-        // last argument, and since arguments start at index 1 that's `arg_count`.
-        let va_list_arg = callee_fn_abi.c_variadic.then(|| mir::Local::from_usize(body.arg_count));
-
         // During argument passing, we want retagging with protectors.
         M::with_retag_mode(self, RetagMode::FnEntry, |ecx| {
             for local in body.args_iter() {
@@ -466,7 +468,32 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 // type, but the result gets cached so this avoids calling the instantiation
                 // query *again* the next time this local is accessed.
                 let ty = ecx.layout_of_local(ecx.frame(), local, None)?.ty;
-                if Some(local) == va_list_arg {
+
+                // Some arguments are special: the first (`self`) argument of a non-capturing
+                // closure; the va_list argument; and the spread_arg.
+                if is_non_capturing_closure && local == mir::Local::arg(0) {
+                    assert!(va_list_arg.is_none());
+                    assert!(Some(local) != body.spread_arg);
+                    // This argument might be missing on the caller side. So just initialize it in
+                    // the callee.
+                    let (callee_arg_idx, callee_abi) = callee_args_abis.next().unwrap();
+                    assert!(callee_abi.layout.is_1zst() && callee_abi.is_ignore());
+                    ecx.storage_live(local)?;
+                    // And skip it in the caller, if present. We can tell whether it is present by
+                    // comparing the number of arguments on the caller and callee side.
+                    if caller_fn_abi.args.len() == callee_fn_abi.args.len() {
+                        let (_caller_arg, caller_abi) = caller_args.next().unwrap();
+                        if !caller_abi.layout.is_1zst() {
+                            // The caller gave us some other, non-ignorable argument.
+                            throw_ub!(AbiMismatchArgument {
+                                arg_idx: callee_arg_idx,
+                                caller_ty: caller_abi.layout.ty,
+                                callee_ty: callee_abi.layout.ty
+                            });
+                        }
+                        assert!(caller_abi.is_ignore());
+                    }
+                } else if Some(local) == va_list_arg {
                     // This is the last callee-side argument of a variadic function.
                     // This argument is a VaList holding the remaining caller-side arguments.
                     ecx.storage_live(local)?;
@@ -476,12 +503,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
 
                     // Consume the remaining arguments by putting them into the variable argument
                     // list.
-                    let varargs = ecx.allocate_varargs(
-                        &mut caller_args,
-                        // "Ignored" arguments aren't actually passed, so the callee should also
-                        // ignore them. (`pass_argument` does this for regular arguments.)
-                        (&mut callee_args_abis).filter(|(_, abi)| !abi.is_ignore()),
-                    )?;
+                    let varargs = ecx.allocate_varargs(&mut caller_args, &mut callee_args_abis)?;
                     // When the frame is dropped, these variable arguments are deallocated.
                     ecx.frame_mut().va_list = varargs.clone();
                     let key = ecx.va_list_ptr(varargs.into());
@@ -507,23 +529,19 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                             &[mir::ProjectionElem::Field(FieldIdx::from_usize(i), field_ty)],
                             *ecx.tcx,
                         );
-                        let (idx, callee_abi) = callee_args_abis.next().unwrap();
                         ecx.pass_argument(
                             &mut caller_args,
-                            callee_abi,
-                            idx,
+                            &mut callee_args_abis,
                             &dest,
                             field_ty,
                             /* already_live */ true,
                         )?;
                     }
                 } else {
                     // Normal argument. Cannot mark it as live yet, it might be unsized!
-                    let (idx, callee_abi) = callee_args_abis.next().unwrap();
                     ecx.pass_argument(
                         &mut caller_args,
-                        callee_abi,
-                        idx,
+                        &mut callee_args_abis,
                         &dest,
                         ty,
                         /* already_live */ false,

compiler/rustc_target/src/target_features.rs

@@ -1,6 +1,44 @@
 //! Declares Rust's target feature names for each target.
 //! Note that these are similar to but not always identical to LLVM's feature names,
 //! and Rust adds some features that do not correspond to LLVM features at all.
+//!
+//! The target features listed here can be used in `#[target_feature]` and `#[cfg(target_feature)]`.
+//! They also do not trigger any warnings when used with `-Ctarget-feature`.
+//!
+//! Note that even unstable (and even entirely unlisted) features can be used with `-Ctarget-feature`
+//! on stable. Using a feature not on the list of Rust target features only emits a warning.
+//! Only `cfg(target_feature)` and `#[target_feature]` actually do any stability gating.
+//! `cfg(target_feature)` for unstable features just works on nightly without any feature gate.
+//! `#[target_feature]` requires a feature gate.
+//!
+//! When adding features to the below lists
+//! check whether they're named already elsewhere in rust
+//! e.g. in stdarch and whether the given name matches LLVM's
+//! if it doesn't, to_llvm_feature in llvm_util in rustc_codegen_llvm needs to be adapted.
+//! Additionally, if the feature is not available in older version of LLVM supported by the current
+//! rust, the same function must be updated to filter out these features to avoid triggering
+//! warnings.
+//!
+//! Also note that all target features listed here must be purely additive: for target_feature 1.1 to
+//! be sound, we can never allow features like `+soft-float` (on x86) to be controlled on a
+//! per-function level, since we would then allow safe calls from functions with `+soft-float` to
+//! functions without that feature!
+//!
+//! It is important for soundness to consider the interaction of target features and the function
+//! call ABI. For example, disabling the `x87` feature on x86 changes how scalar floats are passed as
+//! arguments, so letting people toggle that feature would be unsound. To this end, the
+//! [`Target::abi_required_features`] function computes which target features must and must not be
+//! enabled for any given target, and individual features can also be marked as [`Forbidden`]. See
+//! <https://github.com/rust-lang/rust/issues/116344> for some more context.
+//!
+//! The one exception to features that change the ABI is features that enable larger vector
+//! registers. Those are permitted to be listed here. The `*_FOR_CORRECT_VECTOR_ABI` arrays store
+//! information about which target feature is ABI-required for which vector size; this is used to
+//! ensure that vectors can only be passed via `extern "C"` when the right feature is enabled. (For
+//! the "Rust" ABI we generally pass vectors by-ref exactly to avoid these issues.)
+//! Also see <https://github.com/rust-lang/rust/issues/116558>.
+//!
+//! Stabilizing a target feature requires t-lang approval.
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_macros::StableHash;
 use rustc_span::{Symbol, sym};
@@ -32,9 +70,12 @@ pub enum Stability {
         Symbol,
     ),
     /// This feature can not be set via `-Ctarget-feature` or `#[target_feature]`, it can only be
-    /// set in the target spec. It is never set in `cfg(target_feature)`. Used in
-    /// particular for features are actually ABI configuration flags (not all targets are as nice as
-    /// RISC-V and have an explicit way to set the ABI separate from target features).
+    /// set in the target spec. It is never set in `cfg(target_feature)`. Used in particular for
+    /// features are actually ABI configuration flags (such as "soft-float" on many targets).
+    /// However, "forbidden" target features can still sometimes be enabled via `-Ctarget-cpu` or
+    /// target feature implications (on the Rust/LLVM level). To prevent that, ABI-relevant target
+    /// features are ideally pinned down (required or forbidden) in
+    /// [`Target::abi_required_features`].
     Forbidden {
         reason: &'static str,
         /// True if this is always an error, false if this can be reported as a warning when set via
@@ -102,50 +143,11 @@ impl Stability {
     }
 }
 
-// Here we list target features that rustc "understands": they can be used in `#[target_feature]`
-// and `#[cfg(target_feature)]`. They also do not trigger any warnings when used with
-// `-Ctarget-feature`.
-//
-// Note that even unstable (and even entirely unlisted) features can be used with `-Ctarget-feature`
-// on stable. Using a feature not on the list of Rust target features only emits a warning.
-// Only `cfg(target_feature)` and `#[target_feature]` actually do any stability gating.
-// `cfg(target_feature)` for unstable features just works on nightly without any feature gate.
-// `#[target_feature]` requires a feature gate.
-//
-// When adding features to the below lists
-// check whether they're named already elsewhere in rust
-// e.g. in stdarch and whether the given name matches LLVM's
-// if it doesn't, to_llvm_feature in llvm_util in rustc_codegen_llvm needs to be adapted.
-// Additionally, if the feature is not available in older version of LLVM supported by the current
-// rust, the same function must be updated to filter out these features to avoid triggering
-// warnings.
-//
-// Also note that all target features listed here must be purely additive: for target_feature 1.1 to
-// be sound, we can never allow features like `+soft-float` (on x86) to be controlled on a
-// per-function level, since we would then allow safe calls from functions with `+soft-float` to
-// functions without that feature!
-//
-// It is important for soundness to consider the interaction of targets features and the function
-// call ABI. For example, disabling the `x87` feature on x86 changes how scalar floats are passed as
-// arguments, so letting people toggle that feature would be unsound. To this end, the
-// `abi_required_features` function computes which target features must and must not be enabled for
-// any given target, and individual features can also be marked as `Forbidden`.
-// See https://github.com/rust-lang/rust/issues/116344 for some more context.
-//
-// The one exception to features that change the ABI is features that enable larger vector
-// registers. Those are permitted to be listed here. The `*_FOR_CORRECT_VECTOR_ABI` arrays store
-// information about which target feature is ABI-required for which vector size; this is used to
-// ensure that vectors can only be passed via `extern "C"` when the right feature is enabled. (For
-// the "Rust" ABI we generally pass vectors by-ref exactly to avoid these issues.)
-// Also see https://github.com/rust-lang/rust/issues/116558.
-//
-// Stabilizing a target feature requires t-lang approval.
-
-// If feature A "implies" feature B, then:
-// - when A gets enabled (via `-Ctarget-feature` or `#[target_feature]`), we also enable B
-// - when B gets disabled (via `-Ctarget-feature`), we also disable A
-//
-// Both of these are also applied transitively.
+/// If feature A "implies" feature B, then:
+/// - when A gets enabled (via `-Ctarget-feature` or `#[target_feature]`), we also enable B
+/// - when B gets disabled (via `-Ctarget-feature`), we also disable A
+///
+/// Both of these are also applied transitively.
 type ImpliedFeatures = &'static [&'static str];
 
 static ARM_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[

library/alloc/src/lib.rs

@@ -73,6 +73,7 @@
 // Lints:
 #![deny(unsafe_op_in_unsafe_fn)]
 #![deny(fuzzy_provenance_casts)]
+#![deny(lossy_provenance_casts)]
 #![warn(deprecated_in_future)]
 #![warn(missing_debug_implementations)]
 #![warn(missing_docs)]

library/alloctests/benches/lib.rs

@@ -7,6 +7,7 @@
 #![feature(strict_provenance_lints)]
 #![feature(test)]
 #![deny(fuzzy_provenance_casts)]
+#![deny(lossy_provenance_casts)]
 
 extern crate test;
 

library/alloctests/tests/boxed.rs

@@ -47,9 +47,9 @@ fn box_clone_from_ptr_stability() {
     for size in (0..8).map(|i| 2usize.pow(i)) {
         let control = vec![Dummy { _data: 42 }; size].into_boxed_slice();
         let mut copy = vec![Dummy { _data: 84 }; size].into_boxed_slice();
-        let copy_raw = copy.as_ptr() as usize;
+        let copy_raw = copy.as_ptr();
         copy.clone_from(&control);
-        assert_eq!(copy.as_ptr() as usize, copy_raw);
+        assert_eq!(copy.as_ptr(), copy_raw);
     }
 }
 

library/alloctests/tests/heap.rs

@@ -25,7 +25,7 @@ fn check_overalign_requests<T: Allocator>(allocator: T) {
                     .collect();
                 for &ptr in &pointers {
                     assert_eq!(
-                        (ptr.as_non_null_ptr().as_ptr() as usize) % align,
+                        ptr.as_non_null_ptr().as_ptr().addr() % align,
                         0,
                         "Got a pointer less aligned than requested"
                     )

library/alloctests/tests/lib.rs

@@ -44,6 +44,7 @@
 #![feature(ptr_cast_slice)]
 #![allow(internal_features)]
 #![deny(fuzzy_provenance_casts)]
+#![deny(lossy_provenance_casts)]
 #![deny(unsafe_op_in_unsafe_fn)]
 
 extern crate alloc;

library/alloctests/tests/sort/tests.rs

@@ -746,7 +746,7 @@ fn self_cmp<T: Ord + Clone + Debug, S: Sort>(
         pattern_fn(len).into_iter().map(|val| type_into_fn(val)).collect::<Vec<_>>();
 
     let comparison_fn = |a: &T, b: &T| {
-        assert_ne!(a as *const T as usize, b as *const T as usize);
+        assert_ne!(a as *const T, b as *const T);
         a.cmp(b)
     };
 

library/alloctests/tests/vec.rs

@@ -1110,7 +1110,7 @@ fn test_into_iter_zst() {
     struct AlignedZstWithDrop([u64; 0]);
     impl Drop for AlignedZstWithDrop {
         fn drop(&mut self) {
-            let addr = self as *mut _ as usize;
+            let addr = (self as *mut Self).addr();
             assert!(hint::black_box(addr) % align_of::<u64>() == 0);
         }
     }
@@ -1356,10 +1356,10 @@ fn overaligned_allocations() {
     for i in 0..0x1000 {
         v.reserve_exact(i);
         assert!(v[0].0 == 273);
-        assert!(v.as_ptr() as usize & 0xff == 0);
+        assert!(v.as_ptr().addr() & 0xff == 0);
         v.shrink_to_fit();
         assert!(v[0].0 == 273);
-        assert!(v.as_ptr() as usize & 0xff == 0);
+        assert!(v.as_ptr().addr() & 0xff == 0);
     }
 }
 
@@ -2574,7 +2574,7 @@ fn test_box_zero_allocator() {
 
         unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
             if layout.size() == 0 {
-                let addr = ptr.as_ptr() as usize;
+                let addr = ptr.as_ptr().addr();
                 let mut state = self.state.borrow_mut();
                 std::println!("freeing {addr}");
                 assert!(state.0.remove(&addr), "ZST free that wasn't allocated");

library/core/src/lib.rs

@@ -80,6 +80,7 @@
 #![deny(rust_2021_incompatible_or_patterns)]
 #![deny(unsafe_op_in_unsafe_fn)]
 #![deny(fuzzy_provenance_casts)]
+#![deny(lossy_provenance_casts)]
 #![warn(deprecated_in_future)]
 #![warn(missing_debug_implementations)]
 #![warn(missing_docs)]

library/core/src/ptr/const_ptr.rs

@@ -183,6 +183,7 @@ impl<T: PointeeSized> *const T {
     /// [`with_exposed_provenance`]: with_exposed_provenance
     #[inline(always)]
     #[stable(feature = "exposed_provenance", since = "1.84.0")]
+    #[expect(lossy_provenance_casts, reason = "this *is* the replacement")]
     pub fn expose_provenance(self) -> usize {
         self.cast::<()>() as usize
     }