[beta] backports and stage0 bump

compiler/rustc_borrowck/src/region_infer/opaque_types.rs

@@ -328,26 +328,19 @@ fn check_opaque_type_well_formed<'tcx>(
 
     // Require that the hidden type actually fulfills all the bounds of the opaque type, even without
     // the bounds that the function supplies.
-    let mut obligations = vec![];
-    infcx
-        .insert_hidden_type(
-            OpaqueTypeKey { def_id, args: identity_args },
-            &ObligationCause::misc(definition_span, def_id),
-            param_env,
-            definition_ty,
-            true,
-            &mut obligations,
-        )
-        .unwrap();
-    infcx.add_item_bounds_for_hidden_type(
-        def_id.to_def_id(),
-        identity_args,
-        ObligationCause::misc(definition_span, def_id),
-        param_env,
-        definition_ty,
-        &mut obligations,
-    );
-    ocx.register_obligations(obligations);
+    let opaque_ty = Ty::new_opaque(tcx, def_id.to_def_id(), identity_args);
+    ocx.eq(&ObligationCause::misc(definition_span, def_id), param_env, opaque_ty, definition_ty)
+        .map_err(|err| {
+            infcx
+                .err_ctxt()
+                .report_mismatched_types(
+                    &ObligationCause::misc(definition_span, def_id),
+                    opaque_ty,
+                    definition_ty,
+                    err,
+                )
+                .emit()
+        })?;
 
     // Require the hidden type to be well-formed with only the generics of the opaque type.
     // Defining use functions may have more bounds than the opaque type, which is ok, as long as the

compiler/rustc_infer/src/infer/opaque_types.rs

@@ -145,25 +145,7 @@ impl<'tcx> InferCtxt<'tcx> {
                             return None;
                         }
                     }
-                    DefiningAnchor::Bubble => {
-                        if let ty::Alias(ty::Opaque, _) = b.kind() {
-                            // In bubble mode we don't know which of the two opaque types is supposed to have the other
-                            // as a hidden type (both, none or either one of them could be in its defining scope).
-                            let predicate = ty::PredicateKind::AliasRelate(
-                                a.into(),
-                                b.into(),
-                                ty::AliasRelationDirection::Equate,
-                            );
-                            let obligation = traits::Obligation::new(
-                                self.tcx,
-                                cause.clone(),
-                                param_env,
-                                predicate,
-                            );
-                            let obligations = vec![obligation];
-                            return Some(Ok(InferOk { value: (), obligations }));
-                        }
-                    }
+                    DefiningAnchor::Bubble => {}
                     DefiningAnchor::Error => return None,
                 };
                 if let ty::Alias(ty::Opaque, ty::AliasTy { def_id: b_def_id, .. }) = *b.kind() {

compiler/rustc_passes/src/check_attr.rs

@@ -1767,6 +1767,7 @@ impl CheckAttrVisitor<'_> {
             .collect();
 
         let mut int_reprs = 0;
+        let mut is_explicit_rust = false;
         let mut is_c = false;
         let mut is_simd = false;
         let mut is_transparent = false;
@@ -1778,7 +1779,9 @@ impl CheckAttrVisitor<'_> {
             }
 
             match hint.name_or_empty() {
-                sym::Rust => {}
+                sym::Rust => {
+                    is_explicit_rust = true;
+                }
                 sym::C => {
                     is_c = true;
                     match target {
@@ -1888,12 +1891,16 @@ impl CheckAttrVisitor<'_> {
 
         // Error on repr(transparent, <anything else>).
         if is_transparent && hints.len() > 1 {
-            let hint_spans: Vec<_> = hint_spans.clone().collect();
+            let hint_spans = hint_spans.clone().collect();
             self.tcx.sess.emit_err(errors::TransparentIncompatible {
                 hint_spans,
                 target: target.to_string(),
             });
         }
+        if is_explicit_rust && (int_reprs > 0 || is_c || is_simd) {
+            let hint_spans = hint_spans.clone().collect();
+            self.tcx.sess.emit_err(errors::ReprConflicting { hint_spans });
+        }
         // Warn on repr(u8, u16), repr(C, simd), and c-like-enum-repr(C, u8)
         if (int_reprs > 1)
             || (is_simd && is_c)
@@ -1910,7 +1917,7 @@ impl CheckAttrVisitor<'_> {
                 CONFLICTING_REPR_HINTS,
                 hir_id,
                 hint_spans.collect::<Vec<Span>>(),
-                errors::ReprConflicting,
+                errors::ReprConflictingLint,
             );
         }
     }

compiler/rustc_passes/src/errors.rs

@@ -558,9 +558,16 @@ pub struct ReprIdent {
     pub span: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(passes_repr_conflicting, code = "E0566")]
+pub struct ReprConflicting {
+    #[primary_span]
+    pub hint_spans: Vec<Span>,
+}
+
 #[derive(LintDiagnostic)]
 #[diag(passes_repr_conflicting, code = "E0566")]
-pub struct ReprConflicting;
+pub struct ReprConflictingLint;
 
 #[derive(Diagnostic)]
 #[diag(passes_used_static)]

compiler/rustc_trait_selection/src/traits/fulfill.rs

@@ -6,7 +6,6 @@ use rustc_infer::infer::DefineOpaqueTypes;
 use rustc_infer::traits::ProjectionCacheKey;
 use rustc_infer::traits::{PolyTraitObligation, SelectionError, TraitEngine};
 use rustc_middle::mir::interpret::ErrorHandled;
-use rustc_middle::traits::DefiningAnchor;
 use rustc_middle::ty::abstract_const::NotConstEvaluatable;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_middle::ty::GenericArgsRef;
@@ -626,27 +625,9 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                     }
                 }
                 ty::PredicateKind::Ambiguous => ProcessResult::Unchanged,
-                ty::PredicateKind::AliasRelate(..)
-                    if matches!(self.selcx.infcx.defining_use_anchor, DefiningAnchor::Bubble) =>
-                {
-                    ProcessResult::Unchanged
+                ty::PredicateKind::AliasRelate(..) => {
+                    bug!("AliasRelate is only used for new solver")
                 }
-                ty::PredicateKind::AliasRelate(a, b, relate) => match relate {
-                    ty::AliasRelationDirection::Equate => match self
-                        .selcx
-                        .infcx
-                        .at(&obligation.cause, obligation.param_env)
-                        .eq(DefineOpaqueTypes::Yes, a, b)
-                    {
-                        Ok(inf_ok) => ProcessResult::Changed(mk_pending(inf_ok.into_obligations())),
-                        Err(_) => ProcessResult::Error(FulfillmentErrorCode::CodeSelectionError(
-                            SelectionError::Unimplemented,
-                        )),
-                    },
-                    ty::AliasRelationDirection::Subtype => {
-                        bug!("AliasRelate with subtyping is only used for new solver")
-                    }
-                },
                 ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(ct, ty)) => {
                     match self.selcx.infcx.at(&obligation.cause, obligation.param_env).eq(
                         DefineOpaqueTypes::No,

compiler/rustc_trait_selection/src/traits/project.rs

@@ -1233,7 +1233,7 @@ fn opt_normalize_projection_type<'a, 'b, 'tcx>(
 
             let projected_term = selcx.infcx.resolve_vars_if_possible(projected_term);
 
-            let result = if projected_term.has_projections() {
+            let mut result = if projected_term.has_projections() {
                 let mut normalizer = AssocTypeNormalizer::new(
                     selcx,
                     param_env,
@@ -1243,14 +1243,14 @@ fn opt_normalize_projection_type<'a, 'b, 'tcx>(
                 );
                 let normalized_ty = normalizer.fold(projected_term);
 
-                let mut deduped = SsoHashSet::with_capacity(projected_obligations.len());
-                projected_obligations.retain(|obligation| deduped.insert(obligation.clone()));
-
                 Normalized { value: normalized_ty, obligations: projected_obligations }
             } else {
                 Normalized { value: projected_term, obligations: projected_obligations }
             };
 
+            let mut deduped = SsoHashSet::with_capacity(result.obligations.len());
+            result.obligations.retain(|obligation| deduped.insert(obligation.clone()));
+
             if use_cache {
                 infcx.inner.borrow_mut().projection_cache().insert_term(cache_key, result.clone());
             }

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -38,7 +38,6 @@ use rustc_infer::traits::TraitObligation;
 use rustc_middle::dep_graph::dep_kinds;
 use rustc_middle::dep_graph::DepNodeIndex;
 use rustc_middle::mir::interpret::ErrorHandled;
-use rustc_middle::traits::DefiningAnchor;
 use rustc_middle::ty::abstract_const::NotConstEvaluatable;
 use rustc_middle::ty::fold::BottomUpFolder;
 use rustc_middle::ty::relate::TypeRelation;
@@ -1003,27 +1002,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                         }
                     }
                 }
-                ty::PredicateKind::AliasRelate(..)
-                    if matches!(self.infcx.defining_use_anchor, DefiningAnchor::Bubble) =>
-                {
-                    Ok(EvaluatedToAmbig)
+                ty::PredicateKind::AliasRelate(..) => {
+                    bug!("AliasRelate is only used for new solver")
                 }
-                ty::PredicateKind::AliasRelate(a, b, relate) => match relate {
-                    ty::AliasRelationDirection::Equate => match self
-                        .infcx
-                        .at(&obligation.cause, obligation.param_env)
-                        .eq(DefineOpaqueTypes::Yes, a, b)
-                    {
-                        Ok(inf_ok) => self.evaluate_predicates_recursively(
-                            previous_stack,
-                            inf_ok.into_obligations(),
-                        ),
-                        Err(_) => Ok(EvaluatedToErr),
-                    },
-                    ty::AliasRelationDirection::Subtype => {
-                        bug!("AliasRelate subtyping is only used for new solver")
-                    }
-                },
                 ty::PredicateKind::Ambiguous => Ok(EvaluatedToAmbig),
                 ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(ct, ty)) => {
                     match self.infcx.at(&obligation.cause, obligation.param_env).eq(

library/core/src/lib.rs

@@ -196,7 +196,6 @@
 //
 // Language features:
 // tidy-alphabetical-start
-#![cfg_attr(not(bootstrap), feature(effects))]
 #![feature(abi_unadjusted)]
 #![feature(adt_const_params)]
 #![feature(allow_internal_unsafe)]

src/librustdoc/clean/mod.rs

@@ -542,7 +542,7 @@ fn clean_generic_param_def<'tcx>(
                 },
             )
         }
-        ty::GenericParamDefKind::Const { has_default, .. } => (
+        ty::GenericParamDefKind::Const { has_default, is_host_effect } => (
             def.name,
             GenericParamDefKind::Const {
                 ty: Box::new(clean_middle_ty(
@@ -562,6 +562,7 @@ fn clean_generic_param_def<'tcx>(
                     )),
                     false => None,
                 },
+                is_host_effect,
             },
         ),
     };
@@ -618,6 +619,7 @@ fn clean_generic_param<'tcx>(
                 ty: Box::new(clean_ty(ty, cx)),
                 default: default
                     .map(|ct| Box::new(ty::Const::from_anon_const(cx.tcx, ct.def_id).to_string())),
+                is_host_effect: cx.tcx.has_attr(param.def_id, sym::rustc_host),
             },
         ),
     };
@@ -2540,14 +2542,22 @@ fn clean_generic_args<'tcx>(
         let args = generic_args
             .args
             .iter()
-            .map(|arg| match arg {
-                hir::GenericArg::Lifetime(lt) if !lt.is_anonymous() => {
-                    GenericArg::Lifetime(clean_lifetime(*lt, cx))
-                }
-                hir::GenericArg::Lifetime(_) => GenericArg::Lifetime(Lifetime::elided()),
-                hir::GenericArg::Type(ty) => GenericArg::Type(clean_ty(ty, cx)),
-                hir::GenericArg::Const(ct) => GenericArg::Const(Box::new(clean_const(ct, cx))),
-                hir::GenericArg::Infer(_inf) => GenericArg::Infer,
+            .filter_map(|arg| {
+                Some(match arg {
+                    hir::GenericArg::Lifetime(lt) if !lt.is_anonymous() => {
+                        GenericArg::Lifetime(clean_lifetime(*lt, cx))
+                    }
+                    hir::GenericArg::Lifetime(_) => GenericArg::Lifetime(Lifetime::elided()),
+                    hir::GenericArg::Type(ty) => GenericArg::Type(clean_ty(ty, cx)),
+                    // FIXME(effects): This will still emit `<true>` for non-const impls of const traits
+                    hir::GenericArg::Const(ct)
+                        if cx.tcx.has_attr(ct.value.def_id, sym::rustc_host) =>
+                    {
+                        return None;
+                    }
+                    hir::GenericArg::Const(ct) => GenericArg::Const(Box::new(clean_const(ct, cx))),
+                    hir::GenericArg::Infer(_inf) => GenericArg::Infer,
+                })
             })
             .collect::<Vec<_>>()
             .into();

src/librustdoc/clean/types.rs

@@ -1315,7 +1315,7 @@ impl WherePredicate {
 pub(crate) enum GenericParamDefKind {
     Lifetime { outlives: Vec<Lifetime> },
     Type { did: DefId, bounds: Vec<GenericBound>, default: Option<Box<Type>>, synthetic: bool },
-    Const { ty: Box<Type>, default: Option<Box<String>> },
+    Const { ty: Box<Type>, default: Option<Box<String>>, is_host_effect: bool },
 }
 
 impl GenericParamDefKind {
@@ -1335,9 +1335,10 @@ impl GenericParamDef {
         Self { name, kind: GenericParamDefKind::Lifetime { outlives: Vec::new() } }
     }
 
-    pub(crate) fn is_synthetic_type_param(&self) -> bool {
+    pub(crate) fn is_synthetic_param(&self) -> bool {
         match self.kind {
-            GenericParamDefKind::Lifetime { .. } | GenericParamDefKind::Const { .. } => false,
+            GenericParamDefKind::Lifetime { .. } => false,
+            GenericParamDefKind::Const { is_host_effect, .. } => is_host_effect,
             GenericParamDefKind::Type { synthetic, .. } => synthetic,
         }
     }

src/librustdoc/clean/utils.rs

@@ -104,6 +104,10 @@ pub(crate) fn ty_args_to_args<'tcx>(
                     arg: index,
                 }),
             ))),
+            // FIXME(effects): this relies on the host effect being called `host`, which users could also name
+            // their const generics.
+            // FIXME(effects): this causes `host = true` and `host = false` generics to also be emitted.
+            GenericArgKind::Const(ct) if let ty::ConstKind::Param(p) = ct.kind() && p.name == sym::host => None,
             GenericArgKind::Const(ct) => {
                 Some(GenericArg::Const(Box::new(clean_middle_const(kind.rebind(ct), cx))))
             }

src/librustdoc/html/format.rs

@@ -250,8 +250,7 @@ impl clean::Generics {
         cx: &'a Context<'tcx>,
     ) -> impl fmt::Display + 'a + Captures<'tcx> {
         display_fn(move |f| {
-            let mut real_params =
-                self.params.iter().filter(|p| !p.is_synthetic_type_param()).peekable();
+            let mut real_params = self.params.iter().filter(|p| !p.is_synthetic_param()).peekable();
             if real_params.peek().is_none() {
                 return Ok(());
             }

src/librustdoc/json/conversions.rs

@@ -453,7 +453,7 @@ impl FromWithTcx<clean::GenericParamDefKind> for GenericParamDefKind {
                 default: default.map(|x| (*x).into_tcx(tcx)),
                 synthetic,
             },
-            Const { ty, default } => GenericParamDefKind::Const {
+            Const { ty, default, is_host_effect: _ } => GenericParamDefKind::Const {
                 type_: (*ty).into_tcx(tcx),
                 default: default.map(|x| *x),
             },
@@ -491,12 +491,14 @@ impl FromWithTcx<clean::WherePredicate> for WherePredicate {
                                 default: default.map(|ty| (*ty).into_tcx(tcx)),
                                 synthetic,
                             },
-                            clean::GenericParamDefKind::Const { ty, default } => {
-                                GenericParamDefKind::Const {
-                                    type_: (*ty).into_tcx(tcx),
-                                    default: default.map(|d| *d),
-                                }
-                            }
+                            clean::GenericParamDefKind::Const {
+                                ty,
+                                default,
+                                is_host_effect: _,
+                            } => GenericParamDefKind::Const {
+                                type_: (*ty).into_tcx(tcx),
+                                default: default.map(|d| *d),
+                            },
                         };
                         GenericParamDef { name, kind }
                     })

src/librustdoc/lib.rs

@@ -6,6 +6,7 @@
 #![feature(array_methods)]
 #![feature(assert_matches)]
 #![feature(box_patterns)]
+#![feature(if_let_guard)]
 #![feature(impl_trait_in_assoc_type)]
 #![feature(iter_intersperse)]
 #![feature(lazy_cell)]