Auto merge of #132943 - matthiaskrgr:rollup-164l3ej, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - #132651 (Remove attributes from generics in built-in derive macros)
 - #132668 (Feature gate yield expressions not in 2024)
 - #132771 (test(configure): cover `parse_args` in `src/bootstrap/configure.py`)
 - #132895 (Generalize `NonNull::from_raw_parts` per ACP362)
 - #132914 (Update grammar in std::cell docs.)
 - #132927 (Consolidate type system const evaluation under `traits::evaluate_const`)
 - #132935 (Make sure to ignore elided lifetimes when pointing at args for fulfillment errors)
 - #132941 (Subtree update of `rust-analyzer`)

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

Author: bors

Diff for: compiler/rustc_ast_passes/src/feature_gate.rs

@@ -523,9 +523,18 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
         "consider removing `for<...>`"
     );
     gate_all!(more_qualified_paths, "usage of qualified paths in this context is experimental");
-    for &span in spans.get(&sym::yield_expr).iter().copied().flatten() {
-        if !span.at_least_rust_2024() {
-            gate!(&visitor, coroutines, span, "yield syntax is experimental");
+    // yield can be enabled either by `coroutines` or `gen_blocks`
+    if let Some(spans) = spans.get(&sym::yield_expr) {
+        for span in spans {
+            if (!visitor.features.coroutines() && !span.allows_unstable(sym::coroutines))
+                && (!visitor.features.gen_blocks() && !span.allows_unstable(sym::gen_blocks))
+            {
+                #[allow(rustc::untranslatable_diagnostic)]
+                // Don't know which of the two features to include in the
+                // error message, so I am arbitrarily picking one.
+                feature_err(&visitor.sess, sym::coroutines, *span, "yield syntax is experimental")
+                    .emit();
+            }
         }
     }
     gate_all!(gen_blocks, "gen blocks are experimental");

Diff for: compiler/rustc_builtin_macros/src/deriving/generic/mod.rs

@@ -680,6 +680,12 @@ impl<'a> TraitDef<'a> {
                     param_clone
                 }
             })
+            .map(|mut param| {
+                // Remove all attributes, because there might be helper attributes
+                // from other macros that will not be valid in the expanded implementation.
+                param.attrs.clear();
+                param
+            })
             .collect();
 
         // and similarly for where clauses

Diff for: compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -1477,7 +1477,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 }
             }
         } else if self.tcx.features().generic_const_exprs() {
-            ct.normalize_internal(self.tcx, self.param_env)
+            rustc_trait_selection::traits::evaluate_const(&self.infcx, ct, self.param_env)
         } else {
             ct
         }

Diff for: compiler/rustc_hir_typeck/src/fn_ctxt/adjust_fulfillment_errors.rs

@@ -316,12 +316,24 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             .tcx
             .generics_of(def_id)
             .own_args(ty::GenericArgs::identity_for_item(self.tcx, def_id));
-        let Some((index, _)) =
-            own_args.iter().enumerate().find(|(_, arg)| **arg == param_to_point_at)
-        else {
+        let Some(mut index) = own_args.iter().position(|arg| *arg == param_to_point_at) else {
             return false;
         };
-        let Some(arg) = segment.args().args.get(index) else {
+        // SUBTLE: We may or may not turbofish lifetime arguments, which will
+        // otherwise be elided. if our "own args" starts with a lifetime, but
+        // the args list does not, then we should chop off all of the lifetimes,
+        // since they're all elided.
+        let segment_args = segment.args().args;
+        if matches!(own_args[0].unpack(), ty::GenericArgKind::Lifetime(_))
+            && segment_args.first().is_some_and(|arg| arg.is_ty_or_const())
+            && let Some(offset) = own_args.iter().position(|arg| {
+                matches!(arg.unpack(), ty::GenericArgKind::Type(_) | ty::GenericArgKind::Const(_))
+            })
+            && let Some(new_index) = index.checked_sub(offset)
+        {
+            index = new_index;
+        }
+        let Some(arg) = segment_args.get(index) else {
             return false;
         };
         error.obligation.cause.span = arg

Diff for: compiler/rustc_infer/src/infer/mod.rs

@@ -25,10 +25,10 @@ use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_macros::extension;
 pub use rustc_macros::{TypeFoldable, TypeVisitable};
+use rustc_middle::bug;
 use rustc_middle::infer::canonical::{CanonicalQueryInput, CanonicalVarValues};
 use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableValue, ConstVidKey};
 use rustc_middle::mir::ConstraintCategory;
-use rustc_middle::mir::interpret::{ErrorHandled, EvalToValTreeResult};
 use rustc_middle::traits::select;
 pub use rustc_middle::ty::IntVarValue;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
@@ -40,7 +40,6 @@ use rustc_middle::ty::{
     self, ConstVid, FloatVid, GenericArg, GenericArgKind, GenericArgs, GenericArgsRef,
     GenericParamDefKind, InferConst, IntVid, Ty, TyCtxt, TyVid, TypingMode,
 };
-use rustc_middle::{bug, span_bug};
 use rustc_span::Span;
 use rustc_span::symbol::Symbol;
 use rustc_type_ir::solve::Reveal;
@@ -1279,84 +1278,6 @@ impl<'tcx> InferCtxt<'tcx> {
         u
     }
 
-    pub fn try_const_eval_resolve(
-        &self,
-        param_env: ty::ParamEnv<'tcx>,
-        unevaluated: ty::UnevaluatedConst<'tcx>,
-        span: Span,
-    ) -> Result<ty::Const<'tcx>, ErrorHandled> {
-        match self.const_eval_resolve(param_env, unevaluated, span) {
-            Ok(Ok(val)) => Ok(ty::Const::new_value(
-                self.tcx,
-                val,
-                self.tcx.type_of(unevaluated.def).instantiate(self.tcx, unevaluated.args),
-            )),
-            Ok(Err(bad_ty)) => {
-                let tcx = self.tcx;
-                let def_id = unevaluated.def;
-                span_bug!(
-                    tcx.def_span(def_id),
-                    "unable to construct a valtree for the unevaluated constant {:?}: type {bad_ty} is not valtree-compatible",
-                    unevaluated
-                );
-            }
-            Err(err) => Err(err),
-        }
-    }
-
-    /// Resolves and evaluates a constant.
-    ///
-    /// The constant can be located on a trait like `<A as B>::C`, in which case the given
-    /// generic parameters and environment are used to resolve the constant. Alternatively if the
-    /// constant has generic parameters in scope the instantiations are used to evaluate the value
-    /// of the constant. For example in `fn foo<T>() { let _ = [0; bar::<T>()]; }` the repeat count
-    /// constant `bar::<T>()` requires a instantiation for `T`, if the instantiation for `T` is
-    /// still too generic for the constant to be evaluated then `Err(ErrorHandled::TooGeneric)` is
-    /// returned.
-    ///
-    /// This handles inferences variables within both `param_env` and `args` by
-    /// performing the operation on their respective canonical forms.
-    #[instrument(skip(self), level = "debug")]
-    pub fn const_eval_resolve(
-        &self,
-        mut param_env: ty::ParamEnv<'tcx>,
-        unevaluated: ty::UnevaluatedConst<'tcx>,
-        span: Span,
-    ) -> EvalToValTreeResult<'tcx> {
-        let mut args = self.resolve_vars_if_possible(unevaluated.args);
-        debug!(?args);
-
-        // Postpone the evaluation of constants whose args depend on inference
-        // variables
-        let tcx = self.tcx;
-        if args.has_non_region_infer() {
-            if let Some(ct) = tcx.thir_abstract_const(unevaluated.def)? {
-                let ct = tcx.expand_abstract_consts(ct.instantiate(tcx, args));
-                if let Err(e) = ct.error_reported() {
-                    return Err(ErrorHandled::Reported(e.into(), span));
-                } else if ct.has_non_region_infer() || ct.has_non_region_param() {
-                    return Err(ErrorHandled::TooGeneric(span));
-                } else {
-                    args = replace_param_and_infer_args_with_placeholder(tcx, args);
-                }
-            } else {
-                args = GenericArgs::identity_for_item(tcx, unevaluated.def);
-                param_env = tcx.param_env(unevaluated.def);
-            }
-        }
-
-        let param_env_erased = tcx.erase_regions(param_env);
-        let args_erased = tcx.erase_regions(args);
-        debug!(?param_env_erased);
-        debug!(?args_erased);
-
-        let unevaluated = ty::UnevaluatedConst { def: unevaluated.def, args: args_erased };
-
-        // The return value is the evaluated value which doesn't contain any reference to inference
-        // variables, thus we don't need to instantiate back the original values.
-        tcx.const_eval_resolve_for_typeck(param_env_erased, unevaluated, span)
-    }
-
     /// The returned function is used in a fast path. If it returns `true` the variable is
     /// unchanged, `false` indicates that the status is unknown.
     #[inline]
@@ -1622,61 +1543,6 @@ impl RegionVariableOrigin {
     }
 }
 
-/// Replaces args that reference param or infer variables with suitable
-/// placeholders. This function is meant to remove these param and infer
-/// args when they're not actually needed to evaluate a constant.
-fn replace_param_and_infer_args_with_placeholder<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    args: GenericArgsRef<'tcx>,
-) -> GenericArgsRef<'tcx> {
-    struct ReplaceParamAndInferWithPlaceholder<'tcx> {
-        tcx: TyCtxt<'tcx>,
-        idx: u32,
-    }
-
-    impl<'tcx> TypeFolder<TyCtxt<'tcx>> for ReplaceParamAndInferWithPlaceholder<'tcx> {
-        fn cx(&self) -> TyCtxt<'tcx> {
-            self.tcx
-        }
-
-        fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
-            if let ty::Infer(_) = t.kind() {
-                let idx = {
-                    let idx = self.idx;
-                    self.idx += 1;
-                    idx
-                };
-                Ty::new_placeholder(self.tcx, ty::PlaceholderType {
-                    universe: ty::UniverseIndex::ROOT,
-                    bound: ty::BoundTy {
-                        var: ty::BoundVar::from_u32(idx),
-                        kind: ty::BoundTyKind::Anon,
-                    },
-                })
-            } else {
-                t.super_fold_with(self)
-            }
-        }
-
-        fn fold_const(&mut self, c: ty::Const<'tcx>) -> ty::Const<'tcx> {
-            if let ty::ConstKind::Infer(_) = c.kind() {
-                ty::Const::new_placeholder(self.tcx, ty::PlaceholderConst {
-                    universe: ty::UniverseIndex::ROOT,
-                    bound: ty::BoundVar::from_u32({
-                        let idx = self.idx;
-                        self.idx += 1;
-                        idx
-                    }),
-                })
-            } else {
-                c.super_fold_with(self)
-            }
-        }
-    }
-
-    args.fold_with(&mut ReplaceParamAndInferWithPlaceholder { tcx, idx: 0 })
-}
-
 impl<'tcx> InferCtxt<'tcx> {
     /// Given a [`hir::Block`], get the span of its last expression or
     /// statement, peeling off any inner blocks.

Diff for: compiler/rustc_middle/src/mir/consts.rs

@@ -1,17 +1,17 @@
 use std::fmt::{self, Debug, Display, Formatter};
 
-use either::Either;
 use rustc_abi::{HasDataLayout, Size};
 use rustc_hir::def_id::DefId;
 use rustc_macros::{HashStable, Lift, TyDecodable, TyEncodable, TypeFoldable, TypeVisitable};
 use rustc_session::RemapFileNameExt;
 use rustc_session::config::RemapPathScopeComponents;
 use rustc_span::{DUMMY_SP, Span};
+use rustc_type_ir::visit::TypeVisitableExt;
 
 use crate::mir::interpret::{AllocId, ConstAllocation, ErrorHandled, Scalar, alloc_range};
 use crate::mir::{Promoted, pretty_print_const_value};
 use crate::ty::print::{pretty_print_const, with_no_trimmed_paths};
-use crate::ty::{self, GenericArgsRef, ScalarInt, Ty, TyCtxt};
+use crate::ty::{self, ConstKind, GenericArgsRef, ScalarInt, Ty, TyCtxt};
 
 ///////////////////////////////////////////////////////////////////////////
 /// Evaluated Constants
@@ -319,15 +319,13 @@ impl<'tcx> Const<'tcx> {
     ) -> Result<ConstValue<'tcx>, ErrorHandled> {
         match self {
             Const::Ty(_, c) => {
-                // We want to consistently have a "clean" value for type system constants (i.e., no
-                // data hidden in the padding), so we always go through a valtree here.
-                match c.eval_valtree(tcx, param_env, span) {
-                    Ok((ty, val)) => Ok(tcx.valtree_to_const_val((ty, val))),
-                    Err(Either::Left(_bad_ty)) => Err(tcx
-                        .dcx()
-                        .delayed_bug("`mir::Const::eval` called on a non-valtree-compatible type")
-                        .into()),
-                    Err(Either::Right(e)) => Err(e),
+                if c.has_non_region_param() {
+                    return Err(ErrorHandled::TooGeneric(span));
+                }
+
+                match c.kind() {
+                    ConstKind::Value(ty, val) => Ok(tcx.valtree_to_const_val((ty, val))),
+                    _ => Err(tcx.dcx().delayed_bug("Unevaluated `ty::Const` in MIR body").into()),
                 }
             }
             Const::Unevaluated(uneval, _) => {

Diff for: compiler/rustc_middle/src/ty/consts.rs

@@ -1,4 +1,3 @@
-use either::Either;
 use rustc_data_structures::intern::Interned;
 use rustc_error_messages::MultiSpan;
 use rustc_hir::def::{DefKind, Res};
@@ -9,7 +8,7 @@ use rustc_type_ir::{self as ir, TypeFlags, WithCachedTypeInfo};
 use tracing::{debug, instrument};
 
 use crate::middle::resolve_bound_vars as rbv;
-use crate::mir::interpret::{ErrorHandled, LitToConstInput, Scalar};
+use crate::mir::interpret::{LitToConstInput, Scalar};
 use crate::ty::{self, GenericArgs, ParamEnv, ParamEnvAnd, Ty, TyCtxt, TypeVisitableExt};
 
 mod int;
@@ -18,7 +17,7 @@ mod valtree;
 
 pub use int::*;
 pub use kind::*;
-use rustc_span::{DUMMY_SP, ErrorGuaranteed, Span};
+use rustc_span::{DUMMY_SP, ErrorGuaranteed};
 pub use valtree::*;
 
 pub type ConstKind<'tcx> = ir::ConstKind<TyCtxt<'tcx>>;
@@ -363,60 +362,6 @@ impl<'tcx> Const<'tcx> {
         Self::from_bits(tcx, n as u128, ParamEnv::empty().and(tcx.types.usize))
     }
 
-    /// Returns the evaluated constant as a valtree;
-    /// if that fails due to a valtree-incompatible type, indicate which type that is
-    /// by returning `Err(Left(bad_type))`.
-    #[inline]
-    pub fn eval_valtree(
-        self,
-        tcx: TyCtxt<'tcx>,
-        param_env: ParamEnv<'tcx>,
-        span: Span,
-    ) -> Result<(Ty<'tcx>, ValTree<'tcx>), Either<Ty<'tcx>, ErrorHandled>> {
-        assert!(!self.has_escaping_bound_vars(), "escaping vars in {self:?}");
-        match self.kind() {
-            ConstKind::Unevaluated(unevaluated) => {
-                // FIXME(eddyb) maybe the `const_eval_*` methods should take
-                // `ty::ParamEnvAnd` instead of having them separate.
-                let (param_env, unevaluated) = unevaluated.prepare_for_eval(tcx, param_env);
-                // try to resolve e.g. associated constants to their definition on an impl, and then
-                // evaluate the const.
-                match tcx.const_eval_resolve_for_typeck(param_env, unevaluated, span) {
-                    Ok(Ok(c)) => {
-                        Ok((tcx.type_of(unevaluated.def).instantiate(tcx, unevaluated.args), c))
-                    }
-                    Ok(Err(bad_ty)) => Err(Either::Left(bad_ty)),
-                    Err(err) => Err(Either::Right(err)),
-                }
-            }
-            ConstKind::Value(ty, val) => Ok((ty, val)),
-            ConstKind::Error(g) => Err(Either::Right(g.into())),
-            ConstKind::Param(_)
-            | ConstKind::Infer(_)
-            | ConstKind::Bound(_, _)
-            | ConstKind::Placeholder(_)
-            | ConstKind::Expr(_) => Err(Either::Right(ErrorHandled::TooGeneric(span))),
-        }
-    }
-
-    /// Normalizes the constant to a value or an error if possible.
-    #[inline]
-    pub fn normalize_internal(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Self {
-        match self.eval_valtree(tcx, param_env, DUMMY_SP) {
-            Ok((ty, val)) => Self::new_value(tcx, val, ty),
-            Err(Either::Left(_bad_ty)) => {
-                // This can happen when we run on ill-typed code.
-                Self::new_error(
-                    tcx,
-                    tcx.dcx()
-                        .delayed_bug("`ty::Const::eval` called on a non-valtree-compatible type"),
-                )
-            }
-            Err(Either::Right(ErrorHandled::Reported(r, _span))) => Self::new_error(tcx, r.into()),
-            Err(Either::Right(ErrorHandled::TooGeneric(_span))) => self,
-        }
-    }
-
     /// Panics if self.kind != ty::ConstKind::Value
     pub fn to_valtree(self) -> (ty::ValTree<'tcx>, Ty<'tcx>) {
         match self.kind() {