Auto merge of rust-lang#131988 - matthiaskrgr:rollup-tx173wn, r=matth…

…iaskrgr

Rollup of 4 pull requests

Successful merges:

 - rust-lang#126588 (Added more scenarios where comma to be removed in the function arg)
 - rust-lang#131728 (bootstrap: extract builder cargo to its own module)
 - rust-lang#131968 (Rip out old effects var handling code from traits)
 - rust-lang#131981 (Remove the `BoundConstness::NotConst` variant)

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

compiler/rustc_const_eval/src/check_consts/qualifs.rs

@@ -6,13 +6,10 @@ use rustc_errors::ErrorGuaranteed;
 use rustc_hir::LangItem;
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::mir::*;
-use rustc_middle::traits::BuiltinImplSource;
 use rustc_middle::ty::{self, AdtDef, GenericArgsRef, Ty};
 use rustc_middle::{bug, mir};
-use rustc_trait_selection::traits::{
-    ImplSource, Obligation, ObligationCause, ObligationCtxt, SelectionContext,
-};
-use tracing::{instrument, trace};
+use rustc_trait_selection::traits::{Obligation, ObligationCause, ObligationCtxt};
+use tracing::instrument;
 
 use super::ConstCx;
 
@@ -195,50 +192,8 @@ impl Qualif for NeedsNonConstDrop {
             return false;
         }
 
-        // FIXME(effects): If `destruct` is not a `const_trait`,
-        // or effects are disabled in this crate, then give up.
-        let destruct_def_id = cx.tcx.require_lang_item(LangItem::Destruct, Some(cx.body.span));
-        if !cx.tcx.has_host_param(destruct_def_id) || !cx.tcx.features().effects {
-            return NeedsDrop::in_any_value_of_ty(cx, ty);
-        }
-
-        let obligation = Obligation::new(
-            cx.tcx,
-            ObligationCause::dummy_with_span(cx.body.span),
-            cx.param_env,
-            ty::TraitRef::new(cx.tcx, destruct_def_id, [
-                ty::GenericArg::from(ty),
-                ty::GenericArg::from(cx.tcx.expected_host_effect_param_for_body(cx.def_id())),
-            ]),
-        );
-
-        let infcx = cx.tcx.infer_ctxt().build();
-        let mut selcx = SelectionContext::new(&infcx);
-        let Some(impl_src) = selcx.select(&obligation).ok().flatten() else {
-            // If we couldn't select a const destruct candidate, then it's bad
-            return true;
-        };
-
-        trace!(?impl_src);
-
-        if !matches!(
-            impl_src,
-            ImplSource::Builtin(BuiltinImplSource::Misc, _) | ImplSource::Param(_)
-        ) {
-            // If our const destruct candidate is not ConstDestruct or implied by the param env,
-            // then it's bad
-            return true;
-        }
-
-        if impl_src.borrow_nested_obligations().is_empty() {
-            return false;
-        }
-
-        // If we had any errors, then it's bad
-        let ocx = ObligationCtxt::new(&infcx);
-        ocx.register_obligations(impl_src.nested_obligations());
-        let errors = ocx.select_all_or_error();
-        !errors.is_empty()
+        // FIXME(effects): Reimplement const drop checking.
+        NeedsDrop::in_any_value_of_ty(cx, ty)
     }
 
     fn in_adt_inherently<'tcx>(

compiler/rustc_hir_analysis/src/bounds.rs

@@ -51,7 +51,7 @@ impl<'tcx> Bounds<'tcx> {
         bound_trait_ref: ty::PolyTraitRef<'tcx>,
         span: Span,
         polarity: ty::PredicatePolarity,
-        constness: ty::BoundConstness,
+        constness: Option<ty::BoundConstness>,
         predicate_filter: PredicateFilter,
     ) {
         let clause = (
@@ -88,19 +88,20 @@ impl<'tcx> Bounds<'tcx> {
         // associated type of `<T as Tr>` and make sure that the effect is compatible.
         let compat_val = match (tcx.def_kind(defining_def_id), constness) {
             // FIXME(effects): revisit the correctness of this
-            (_, ty::BoundConstness::Const) => tcx.consts.false_,
+            (_, Some(ty::BoundConstness::Const)) => tcx.consts.false_,
             // body owners that can have trait bounds
-            (DefKind::Const | DefKind::Fn | DefKind::AssocFn, ty::BoundConstness::ConstIfConst) => {
-                tcx.expected_host_effect_param_for_body(defining_def_id)
-            }
+            (
+                DefKind::Const | DefKind::Fn | DefKind::AssocFn,
+                Some(ty::BoundConstness::ConstIfConst),
+            ) => tcx.expected_host_effect_param_for_body(defining_def_id),
 
-            (_, ty::BoundConstness::NotConst) => {
+            (_, None) => {
                 if !tcx.is_const_trait(bound_trait_ref.def_id()) {
                     return;
                 }
                 tcx.consts.true_
             }
-            (DefKind::Trait, ty::BoundConstness::ConstIfConst) => {
+            (DefKind::Trait, Some(ty::BoundConstness::ConstIfConst)) => {
                 // we are in a trait, where `bound_trait_ref` could be:
                 // (1) a super trait `trait Foo: ~const Bar`.
                 //     - This generates `<Self as Foo>::Effects: TyCompat<<Self as Bar>::Effects>`
@@ -138,7 +139,7 @@ impl<'tcx> Bounds<'tcx> {
                 return;
             }
 
-            (DefKind::Impl { of_trait: true }, ty::BoundConstness::ConstIfConst) => {
+            (DefKind::Impl { of_trait: true }, Some(ty::BoundConstness::ConstIfConst)) => {
                 // this is a where clause on an impl header.
                 // push `<T as Tr>::Effects` into the set for the `Min` bound.
                 let Some(assoc) = tcx.associated_type_for_effects(bound_trait_ref.def_id()) else {
@@ -172,12 +173,12 @@ impl<'tcx> Bounds<'tcx> {
             //
             // FIXME(effects) this is equality for now, which wouldn't be helpful for a non-const implementor
             // that uses a `Bar` that implements `Trait` with `Maybe` effects.
-            (DefKind::AssocTy, ty::BoundConstness::ConstIfConst) => {
+            (DefKind::AssocTy, Some(ty::BoundConstness::ConstIfConst)) => {
                 // FIXME(effects): implement this
                 return;
             }
             // probably illegal in this position.
-            (_, ty::BoundConstness::ConstIfConst) => {
+            (_, Some(ty::BoundConstness::ConstIfConst)) => {
                 tcx.dcx().span_delayed_bug(span, "invalid `~const` encountered");
                 return;
             }

compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs

@@ -171,16 +171,15 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 hir::GenericBound::Trait(poly_trait_ref) => {
                     let (constness, polarity) = match poly_trait_ref.modifiers {
                         hir::TraitBoundModifier::Const => {
-                            (ty::BoundConstness::Const, ty::PredicatePolarity::Positive)
-                        }
-                        hir::TraitBoundModifier::MaybeConst => {
-                            (ty::BoundConstness::ConstIfConst, ty::PredicatePolarity::Positive)
-                        }
-                        hir::TraitBoundModifier::None => {
-                            (ty::BoundConstness::NotConst, ty::PredicatePolarity::Positive)
+                            (Some(ty::BoundConstness::Const), ty::PredicatePolarity::Positive)
                         }
+                        hir::TraitBoundModifier::MaybeConst => (
+                            Some(ty::BoundConstness::ConstIfConst),
+                            ty::PredicatePolarity::Positive,
+                        ),
+                        hir::TraitBoundModifier::None => (None, ty::PredicatePolarity::Positive),
                         hir::TraitBoundModifier::Negative => {
-                            (ty::BoundConstness::NotConst, ty::PredicatePolarity::Negative)
+                            (None, ty::PredicatePolarity::Negative)
                         }
                         hir::TraitBoundModifier::Maybe => continue,
                     };

compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs

@@ -51,7 +51,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             } = self.lower_poly_trait_ref(
                 &trait_bound.trait_ref,
                 trait_bound.span,
-                ty::BoundConstness::NotConst,
+                None,
                 ty::PredicatePolarity::Positive,
                 dummy_self,
                 &mut bounds,

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -652,7 +652,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         &self,
         trait_ref: &hir::TraitRef<'tcx>,
         span: Span,
-        constness: ty::BoundConstness,
+        constness: Option<ty::BoundConstness>,
         polarity: ty::PredicatePolarity,
         self_ty: Ty<'tcx>,
         bounds: &mut Bounds<'tcx>,
@@ -675,7 +675,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             Some(self_ty),
         );
 
-        if let ty::BoundConstness::Const | ty::BoundConstness::ConstIfConst = constness
+        if let Some(constness) = constness
             && !self.tcx().is_const_trait(trait_def_id)
         {
             self.dcx().emit_err(crate::errors::ConstBoundForNonConstTrait {

compiler/rustc_hir_typeck/src/callee.rs

@@ -537,40 +537,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 //
                 // This check is here because there is currently no way to express a trait bound for `FnDef` types only.
                 if let ty::FnDef(def_id, _args) = *arg_ty.kind() {
-                    let fn_once_def_id =
-                        self.tcx.require_lang_item(hir::LangItem::FnOnce, Some(span));
-                    let fn_once_output_def_id =
-                        self.tcx.require_lang_item(hir::LangItem::FnOnceOutput, Some(span));
-                    if self.tcx.has_host_param(fn_once_def_id) {
-                        let const_param: ty::GenericArg<'tcx> =
-                            ([self.tcx.consts.false_, self.tcx.consts.true_])[idx].into();
-                        self.register_predicate(traits::Obligation::new(
-                            self.tcx,
-                            self.misc(span),
-                            self.param_env,
-                            ty::TraitRef::new(self.tcx, fn_once_def_id, [
-                                arg_ty.into(),
-                                fn_sig.inputs()[0].into(),
-                                const_param,
-                            ]),
-                        ));
-
-                        self.register_predicate(traits::Obligation::new(
-                            self.tcx,
-                            self.misc(span),
-                            self.param_env,
-                            ty::ProjectionPredicate {
-                                projection_term: ty::AliasTerm::new(
-                                    self.tcx,
-                                    fn_once_output_def_id,
-                                    [arg_ty.into(), fn_sig.inputs()[0].into(), const_param],
-                                ),
-                                term: fn_sig.output().into(),
-                            },
-                        ));
-
-                        self.select_obligations_where_possible(|_| {});
-                    } else if idx == 0 && !self.tcx.is_const_fn_raw(def_id) {
+                    if idx == 0 && !self.tcx.is_const_fn_raw(def_id) {
                         self.dcx().emit_err(errors::ConstSelectMustBeConst { span });
                     }
                 } else {

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -1097,6 +1097,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let mut only_extras_so_far = errors
             .peek()
             .is_some_and(|first| matches!(first, Error::Extra(arg_idx) if arg_idx.index() == 0));
+        let mut prev_extra_idx = None;
         let mut suggestions = vec![];
         while let Some(error) = errors.next() {
             only_extras_so_far &= matches!(error, Error::Extra(_));
@@ -1165,11 +1166,29 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         //     fn f() {}
                         //   - f(0, 1,)
                         //   + f()
-                        if only_extras_so_far
-                            && !errors
-                                .peek()
-                                .is_some_and(|next_error| matches!(next_error, Error::Extra(_)))
-                        {
+                        let trim_next_comma = match errors.peek() {
+                            Some(Error::Extra(provided_idx))
+                                if only_extras_so_far
+                                    && provided_idx.index() > arg_idx.index() + 1 =>
+                            // If the next Error::Extra ("next") doesn't next to current ("current"),
+                            // fn foo(_: (), _: u32) {}
+                            // - foo("current", (), 1u32, "next")
+                            // + foo((), 1u32)
+                            // If the previous error is not a `Error::Extra`, then do not trim the next comma
+                            // - foo((), "current", 42u32, "next")
+                            // + foo((), 42u32)
+                            {
+                                prev_extra_idx.map_or(true, |prev_extra_idx| {
+                                    prev_extra_idx + 1 == arg_idx.index()
+                                })
+                            }
+                            // If no error left, we need to delete the next comma
+                            None if only_extras_so_far => true,
+                            // Not sure if other error type need to be handled as well
+                            _ => false,
+                        };
+
+                        if trim_next_comma {
                             let next = provided_arg_tys
                                 .get(arg_idx + 1)
                                 .map(|&(_, sp)| sp)
@@ -1192,6 +1211,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             SuggestionText::Remove(_) => SuggestionText::Remove(true),
                             _ => SuggestionText::DidYouMean,
                         };
+                        prev_extra_idx = Some(arg_idx.index())
                     }
                 }
                 Error::Missing(expected_idx) => {

compiler/rustc_middle/src/traits/select.rs

@@ -161,9 +161,7 @@ pub enum SelectionCandidate<'tcx> {
 
     /// Implementation of a `Fn`-family trait by one of the anonymous
     /// types generated for a fn pointer type (e.g., `fn(int) -> int`)
-    FnPointerCandidate {
-        fn_host_effect: ty::Const<'tcx>,
-    },
+    FnPointerCandidate,
 
     TraitAliasCandidate,
 
@@ -180,9 +178,6 @@ pub enum SelectionCandidate<'tcx> {
     BuiltinObjectCandidate,
 
     BuiltinUnsizeCandidate,
-
-    /// Implementation of `const Destruct`, optionally from a custom `impl const Drop`.
-    ConstDestructCandidate(Option<DefId>),
 }
 
 /// The result of trait evaluation. The order is important

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -1956,7 +1956,6 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
         define_scoped_cx!(self);
 
         match constness {
-            ty::BoundConstness::NotConst => {}
             ty::BoundConstness::Const => {
                 p!("const ");
             }
@@ -2948,7 +2947,10 @@ impl<'tcx> ty::TraitPredicate<'tcx> {
 }
 
 #[derive(Copy, Clone, TypeFoldable, TypeVisitable, Lift)]
-pub struct TraitPredPrintWithBoundConstness<'tcx>(ty::TraitPredicate<'tcx>, ty::BoundConstness);
+pub struct TraitPredPrintWithBoundConstness<'tcx>(
+    ty::TraitPredicate<'tcx>,
+    Option<ty::BoundConstness>,
+);
 
 impl<'tcx> fmt::Debug for TraitPredPrintWithBoundConstness<'tcx> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
@@ -2966,7 +2968,7 @@ impl<'tcx> ty::PolyTraitPredicate<'tcx> {
 
     fn print_with_bound_constness(
         self,
-        constness: ty::BoundConstness,
+        constness: Option<ty::BoundConstness>,
     ) -> ty::Binder<'tcx, TraitPredPrintWithBoundConstness<'tcx>> {
         self.map_bound(|trait_pred| TraitPredPrintWithBoundConstness(trait_pred, constness))
     }
@@ -3206,7 +3208,9 @@ define_print_and_forward_display! {
 
     TraitPredPrintWithBoundConstness<'tcx> {
         p!(print(self.0.trait_ref.self_ty()), ": ");
-        p!(pretty_print_bound_constness(self.1));
+        if let Some(constness) = self.1 {
+            p!(pretty_print_bound_constness(constness));
+        }
         if let ty::PredicatePolarity::Negative = self.0.polarity {
             p!("!");
         }

compiler/rustc_middle/src/ty/util.rs

@@ -907,24 +907,6 @@ impl<'tcx> TyCtxt<'tcx> {
         }
     }
 
-    /// Constructs generic args for an item, optionally appending a const effect param type
-    pub fn with_opt_host_effect_param(
-        self,
-        caller_def_id: LocalDefId,
-        callee_def_id: DefId,
-        args: impl IntoIterator<Item: Into<ty::GenericArg<'tcx>>>,
-    ) -> ty::GenericArgsRef<'tcx> {
-        let generics = self.generics_of(callee_def_id);
-        assert_eq!(generics.parent, None);
-
-        let opt_const_param = generics
-            .host_effect_index
-            .is_some()
-            .then(|| ty::GenericArg::from(self.expected_host_effect_param_for_body(caller_def_id)));
-
-        self.mk_args_from_iter(args.into_iter().map(|arg| arg.into()).chain(opt_const_param))
-    }
-
     /// Expand any [weak alias types][weak] contained within the given `value`.
     ///
     /// This should be used over other normalization routines in situations where

compiler/rustc_mir_build/src/build/matches/test.rs

@@ -454,12 +454,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         };
 
         let eq_def_id = self.tcx.require_lang_item(LangItem::PartialEq, Some(source_info.span));
-        let method = trait_method(
-            self.tcx,
-            eq_def_id,
-            sym::eq,
-            self.tcx.with_opt_host_effect_param(self.def_id, eq_def_id, [compare_ty, compare_ty]),
-        );
+        let method = trait_method(self.tcx, eq_def_id, sym::eq, [compare_ty, compare_ty]);
 
         let bool_ty = self.tcx.types.bool;
         let eq_result = self.temp(bool_ty, source_info.span);