Merge from rustc

10 files changed, 179 insertions, 165 deletions

diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
index 970160ba212..b88040a0f98 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
@@ -841,16 +841,17 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                 return None;
             };
 
-        let (closure_def_id, found_args, by_ref_captures) = match *self_ty.kind() {
+        let (closure_def_id, found_args, has_self_borrows) = match *self_ty.kind() {
             ty::Closure(def_id, args) => {
-                (def_id, args.as_closure().sig().map_bound(|sig| sig.inputs()[0]), None)
+                (def_id, args.as_closure().sig().map_bound(|sig| sig.inputs()[0]), false)
             }
             ty::CoroutineClosure(def_id, args) => (
                 def_id,
                 args.as_coroutine_closure()
                     .coroutine_closure_sig()
                     .map_bound(|sig| sig.tupled_inputs_ty),
-                Some(args.as_coroutine_closure().coroutine_captures_by_ref_ty()),
+                !args.as_coroutine_closure().tupled_upvars_ty().is_ty_var()
+                    && args.as_coroutine_closure().has_self_borrows(),
             ),
             _ => return None,
         };
@@ -884,10 +885,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         // If the closure has captures, then perhaps the reason that the trait
         // is unimplemented is because async closures don't implement `Fn`/`FnMut`
         // if they have captures.
-        if let Some(by_ref_captures) = by_ref_captures
-            && let ty::FnPtr(sig_tys, _) = by_ref_captures.kind()
-            && !sig_tys.skip_binder().output().is_unit()
-        {
+        if has_self_borrows && expected_kind != ty::ClosureKind::FnOnce {
             let mut err = self.dcx().create_err(AsyncClosureNotFn {
                 span: self.tcx.def_span(closure_def_id),
                 kind: expected_kind.as_str(),
@@ -1503,11 +1501,11 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                     return None;
                 };
 
-                let Ok(Some(ImplSource::UserDefined(impl_data))) = SelectionContext::new(self)
-                    .poly_select(&obligation.with(
-                        self.tcx,
-                        predicate.kind().rebind(proj.projection_term.trait_ref(self.tcx)),
-                    ))
+                let trait_ref = self.enter_forall_and_leak_universe(
+                    predicate.kind().rebind(proj.projection_term.trait_ref(self.tcx)),
+                );
+                let Ok(Some(ImplSource::UserDefined(impl_data))) =
+                    SelectionContext::new(self).select(&obligation.with(self.tcx, trait_ref))
                 else {
                     return None;
                 };
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs
index d5ee6e2123a..37968386e9a 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs
@@ -429,7 +429,19 @@ impl<'tcx> OnUnimplementedDirective {
                 .next()
                 .ok_or_else(|| tcx.dcx().emit_err(InvalidOnClause::Empty { span }))?;
 
-            match OnUnimplementedCondition::parse(cond) {
+            let generics: Vec<Symbol> = tcx
+                .generics_of(item_def_id)
+                .own_params
+                .iter()
+                .filter_map(|param| {
+                    if matches!(param.kind, GenericParamDefKind::Lifetime) {
+                        None
+                    } else {
+                        Some(param.name)
+                    }
+                })
+                .collect();
+            match OnUnimplementedCondition::parse(cond, &generics) {
                 Ok(condition) => Some(condition),
                 Err(e) => return Err(tcx.dcx().emit_err(e)),
             }
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented_condition.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented_condition.rs
index 13753761f09..e8ea9f2d23e 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented_condition.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented_condition.rs
@@ -26,9 +26,12 @@ impl OnUnimplementedCondition {
         })
     }
 
-    pub(crate) fn parse(input: &MetaItemInner) -> Result<Self, InvalidOnClause> {
+    pub(crate) fn parse(
+        input: &MetaItemInner,
+        generics: &[Symbol],
+    ) -> Result<Self, InvalidOnClause> {
         let span = input.span();
-        let pred = Predicate::parse(input)?;
+        let pred = Predicate::parse(input, generics)?;
         Ok(OnUnimplementedCondition { span, pred })
     }
 }
@@ -52,7 +55,7 @@ enum Predicate {
 }
 
 impl Predicate {
-    fn parse(input: &MetaItemInner) -> Result<Self, InvalidOnClause> {
+    fn parse(input: &MetaItemInner, generics: &[Symbol]) -> Result<Self, InvalidOnClause> {
         let meta_item = match input {
             MetaItemInner::MetaItem(meta_item) => meta_item,
             MetaItemInner::Lit(lit) => {
@@ -69,10 +72,10 @@ impl Predicate {
 
         match meta_item.kind {
             MetaItemKind::List(ref mis) => match predicate.name {
-                sym::any => Ok(Predicate::Any(Predicate::parse_sequence(mis)?)),
-                sym::all => Ok(Predicate::All(Predicate::parse_sequence(mis)?)),
+                sym::any => Ok(Predicate::Any(Predicate::parse_sequence(mis, generics)?)),
+                sym::all => Ok(Predicate::All(Predicate::parse_sequence(mis, generics)?)),
                 sym::not => match &**mis {
-                    [one] => Ok(Predicate::Not(Box::new(Predicate::parse(one)?))),
+                    [one] => Ok(Predicate::Not(Box::new(Predicate::parse(one, generics)?))),
                     [first, .., last] => Err(InvalidOnClause::ExpectedOnePredInNot {
                         span: first.span().to(last.span()),
                     }),
@@ -83,7 +86,7 @@ impl Predicate {
                 }
             },
             MetaItemKind::NameValue(MetaItemLit { symbol, .. }) => {
-                let name = Name::parse(predicate);
+                let name = Name::parse(predicate, generics)?;
                 let value = FilterFormatString::parse(symbol);
                 let kv = NameValue { name, value };
                 Ok(Predicate::Match(kv))
@@ -95,8 +98,11 @@ impl Predicate {
         }
     }
 
-    fn parse_sequence(sequence: &[MetaItemInner]) -> Result<Vec<Self>, InvalidOnClause> {
-        sequence.iter().map(Predicate::parse).collect()
+    fn parse_sequence(
+        sequence: &[MetaItemInner],
+        generics: &[Symbol],
+    ) -> Result<Vec<Self>, InvalidOnClause> {
+        sequence.iter().map(|item| Predicate::parse(item, generics)).collect()
     }
 
     fn eval(&self, eval: &mut impl FnMut(FlagOrNv<'_>) -> bool) -> bool {
@@ -156,14 +162,13 @@ enum Name {
 }
 
 impl Name {
-    fn parse(Ident { name, .. }: Ident) -> Self {
+    fn parse(Ident { name, span }: Ident, generics: &[Symbol]) -> Result<Self, InvalidOnClause> {
         match name {
-            sym::_Self | kw::SelfUpper => Name::SelfUpper,
-            sym::from_desugaring => Name::FromDesugaring,
-            sym::cause => Name::Cause,
-            // FIXME(mejrs) Perhaps we should start checking that
-            // this actually is a valid generic parameter?
-            generic => Name::GenericArg(generic),
+            kw::SelfUpper => Ok(Name::SelfUpper),
+            sym::from_desugaring => Ok(Name::FromDesugaring),
+            sym::cause => Ok(Name::Cause),
+            generic if generics.contains(&generic) => Ok(Name::GenericArg(generic)),
+            invalid_name => Err(InvalidOnClause::InvalidName { invalid_name, span }),
         }
     }
 }
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented_format.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented_format.rs
index ce170f820e1..7c1dfc1728f 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented_format.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented_format.rs
@@ -2,8 +2,8 @@ use std::fmt;
 use std::ops::Range;
 
 use errors::*;
-use rustc_middle::ty::TyCtxt;
 use rustc_middle::ty::print::TraitRefPrintSugared;
+use rustc_middle::ty::{GenericParamDefKind, TyCtxt};
 use rustc_parse_format::{
     Alignment, Argument, Count, FormatSpec, ParseError, ParseMode, Parser, Piece as RpfPiece,
     Position,
@@ -232,48 +232,16 @@ fn parse_arg<'tcx>(
 ) -> FormatArg {
     let (Ctx::RustcOnUnimplemented { tcx, trait_def_id }
     | Ctx::DiagnosticOnUnimplemented { tcx, trait_def_id }) = ctx;
-    let trait_name = tcx.item_ident(*trait_def_id);
-    let generics = tcx.generics_of(trait_def_id);
+
     let span = slice_span(input_span, arg.position_span.clone());
 
     match arg.position {
         // Something like "hello {name}"
         Position::ArgumentNamed(name) => match (ctx, Symbol::intern(name)) {
-            // accepted, but deprecated
-            (Ctx::RustcOnUnimplemented { .. }, sym::_Self) => {
-                warnings
-                    .push(FormatWarning::FutureIncompat { span, help: String::from("use {Self}") });
-                FormatArg::SelfUpper
-            }
-            (
-                Ctx::RustcOnUnimplemented { .. },
-                sym::from_desugaring
-                | sym::crate_local
-                | sym::direct
-                | sym::cause
-                | sym::float
-                | sym::integer_
-                | sym::integral,
-            ) => {
-                warnings.push(FormatWarning::FutureIncompat {
-                    span,
-                    help: String::from("don't use this in a format string"),
-                });
-                FormatArg::AsIs(String::new())
-            }
-
             // Only `#[rustc_on_unimplemented]` can use these
             (Ctx::RustcOnUnimplemented { .. }, sym::ItemContext) => FormatArg::ItemContext,
             (Ctx::RustcOnUnimplemented { .. }, sym::This) => FormatArg::This,
             (Ctx::RustcOnUnimplemented { .. }, sym::Trait) => FormatArg::Trait,
-            // `{ThisTraitsName}`. Some attrs in std use this, but I'd like to change it to the more general `{This}`
-            // because that'll be simpler to parse and extend in the future
-            (Ctx::RustcOnUnimplemented { .. }, name) if name == trait_name.name => {
-                warnings
-                    .push(FormatWarning::FutureIncompat { span, help: String::from("use {This}") });
-                FormatArg::This
-            }
-
             // Any attribute can use these
             (
                 Ctx::RustcOnUnimplemented { .. } | Ctx::DiagnosticOnUnimplemented { .. },
@@ -282,7 +250,10 @@ fn parse_arg<'tcx>(
             (
                 Ctx::RustcOnUnimplemented { .. } | Ctx::DiagnosticOnUnimplemented { .. },
                 generic_param,
-            ) if generics.own_params.iter().any(|param| param.name == generic_param) => {
+            ) if tcx.generics_of(trait_def_id).own_params.iter().any(|param| {
+                !matches!(param.kind, GenericParamDefKind::Lifetime) && param.name == generic_param
+            }) =>
+            {
                 FormatArg::GenericParam { generic_param }
             }
 
@@ -375,39 +346,4 @@ pub mod errors {
     #[diag(trait_selection_missing_options_for_on_unimplemented_attr)]
     #[help]
     pub struct MissingOptionsForOnUnimplementedAttr;
-
-    #[derive(LintDiagnostic)]
-    #[diag(trait_selection_ignored_diagnostic_option)]
-    pub struct IgnoredDiagnosticOption {
-        pub option_name: &'static str,
-        #[label]
-        pub span: Span,
-        #[label(trait_selection_other_label)]
-        pub prev_span: Span,
-    }
-
-    impl IgnoredDiagnosticOption {
-        pub fn maybe_emit_warning<'tcx>(
-            tcx: TyCtxt<'tcx>,
-            item_def_id: DefId,
-            new: Option<Span>,
-            old: Option<Span>,
-            option_name: &'static str,
-        ) {
-            if let (Some(new_item), Some(old_item)) = (new, old) {
-                if let Some(item_def_id) = item_def_id.as_local() {
-                    tcx.emit_node_span_lint(
-                        UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
-                        tcx.local_def_id_to_hir_id(item_def_id),
-                        new_item,
-                        IgnoredDiagnosticOption {
-                            span: new_item,
-                            prev_span: old_item,
-                            option_name,
-                        },
-                    );
-                }
-            }
-        }
-    }
 }
diff --git a/compiler/rustc_trait_selection/src/errors.rs b/compiler/rustc_trait_selection/src/errors.rs
index 8ab4d795c45..779c861637a 100644
--- a/compiler/rustc_trait_selection/src/errors.rs
+++ b/compiler/rustc_trait_selection/src/errors.rs
@@ -72,6 +72,13 @@ pub enum InvalidOnClause {
         span: Span,
         invalid_flag: Symbol,
     },
+    #[diag(trait_selection_rustc_on_unimplemented_invalid_name, code = E0232)]
+    InvalidName {
+        #[primary_span]
+        #[label]
+        span: Span,
+        invalid_name: Symbol,
+    },
 }
 
 #[derive(Diagnostic)]
diff --git a/compiler/rustc_trait_selection/src/solve/delegate.rs b/compiler/rustc_trait_selection/src/solve/delegate.rs
index a60642b953c..b68a7845366 100644
--- a/compiler/rustc_trait_selection/src/solve/delegate.rs
+++ b/compiler/rustc_trait_selection/src/solve/delegate.rs
@@ -5,7 +5,7 @@ use rustc_hir::LangItem;
 use rustc_hir::def_id::{CRATE_DEF_ID, DefId};
 use rustc_infer::infer::canonical::query_response::make_query_region_constraints;
 use rustc_infer::infer::canonical::{
-    Canonical, CanonicalExt as _, CanonicalQueryInput, CanonicalVarInfo, CanonicalVarValues,
+    Canonical, CanonicalExt as _, CanonicalQueryInput, CanonicalVarKind, CanonicalVarValues,
 };
 use rustc_infer::infer::{InferCtxt, RegionVariableOrigin, SubregionOrigin, TyCtxtInferExt};
 use rustc_infer::traits::solve::Goal;
@@ -190,11 +190,11 @@ impl<'tcx> rustc_next_trait_solver::delegate::SolverDelegate for SolverDelegate<
 
     fn instantiate_canonical_var_with_infer(
         &self,
-        cv_info: CanonicalVarInfo<'tcx>,
+        kind: CanonicalVarKind<'tcx>,
         span: Span,
         universe_map: impl Fn(ty::UniverseIndex) -> ty::UniverseIndex,
     ) -> ty::GenericArg<'tcx> {
-        self.0.instantiate_canonical_var(span, cv_info, universe_map)
+        self.0.instantiate_canonical_var(span, kind, universe_map)
     }
 
     fn add_item_bounds_for_hidden_type(
diff --git a/compiler/rustc_trait_selection/src/solve/select.rs b/compiler/rustc_trait_selection/src/solve/select.rs
index 4fdaf740287..1f3168fafb1 100644
--- a/compiler/rustc_trait_selection/src/solve/select.rs
+++ b/compiler/rustc_trait_selection/src/solve/select.rs
@@ -5,7 +5,7 @@ use rustc_infer::traits::solve::inspect::ProbeKind;
 use rustc_infer::traits::solve::{CandidateSource, Certainty, Goal};
 use rustc_infer::traits::{
     BuiltinImplSource, ImplSource, ImplSourceUserDefinedData, Obligation, ObligationCause,
-    PolyTraitObligation, Selection, SelectionError, SelectionResult,
+    Selection, SelectionError, SelectionResult, TraitObligation,
 };
 use rustc_macros::extension;
 use rustc_middle::{bug, span_bug};
@@ -17,7 +17,7 @@ use crate::solve::inspect::{self, ProofTreeInferCtxtExt};
 impl<'tcx> InferCtxt<'tcx> {
     fn select_in_new_trait_solver(
         &self,
-        obligation: &PolyTraitObligation<'tcx>,
+        obligation: &TraitObligation<'tcx>,
     ) -> SelectionResult<'tcx, Selection<'tcx>> {
         assert!(self.next_trait_solver());
 
diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs
index f73603c0053..a9bdb909bdc 100644
--- a/compiler/rustc_trait_selection/src/traits/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/mod.rs
@@ -540,10 +540,13 @@ pub fn try_evaluate_const<'tcx>(
         | ty::ConstKind::Placeholder(_)
         | ty::ConstKind::Expr(_) => Err(EvaluateConstErr::HasGenericsOrInfers),
         ty::ConstKind::Unevaluated(uv) => {
+            let opt_anon_const_kind =
+                (tcx.def_kind(uv.def) == DefKind::AnonConst).then(|| tcx.anon_const_kind(uv.def));
+
             // Postpone evaluation of constants that depend on generic parameters or
             // inference variables.
             //
-            // We use `TypingMode::PostAnalysis`  here which is not *technically* correct
+            // We use `TypingMode::PostAnalysis` here which is not *technically* correct
             // to be revealing opaque types here as borrowcheck has not run yet. However,
             // CTFE itself uses `TypingMode::PostAnalysis` unconditionally even during
             // typeck and not doing so has a lot of (undesirable) fallout (#101478, #119821).
@@ -551,65 +554,95 @@ pub fn try_evaluate_const<'tcx>(
             //
             // FIXME: `const_eval_resolve_for_typeck` should probably just modify the env itself
             // instead of having this logic here
-            let (args, typing_env) = if tcx.features().generic_const_exprs()
-                && uv.has_non_region_infer()
-            {
-                // `feature(generic_const_exprs)` causes anon consts to inherit all parent generics. This can cause
-                // inference variables and generic parameters to show up in `ty::Const` even though the anon const
-                // does not actually make use of them. We handle this case specially and attempt to evaluate anyway.
-                match tcx.thir_abstract_const(uv.def) {
-                    Ok(Some(ct)) => {
-                        let ct = tcx.expand_abstract_consts(ct.instantiate(tcx, uv.args));
-                        if let Err(e) = ct.error_reported() {
-                            return Err(EvaluateConstErr::EvaluationFailure(e));
-                        } else if ct.has_non_region_infer() || ct.has_non_region_param() {
-                            // If the anon const *does* actually use generic parameters or inference variables from
-                            // the generic arguments provided for it, then we should *not* attempt to evaluate it.
-                            return Err(EvaluateConstErr::HasGenericsOrInfers);
-                        } else {
-                            let args = replace_param_and_infer_args_with_placeholder(tcx, uv.args);
-                            let typing_env = infcx
-                                .typing_env(tcx.erase_regions(param_env))
-                                .with_post_analysis_normalized(tcx);
-                            (args, typing_env)
+            let (args, typing_env) = match opt_anon_const_kind {
+                // We handle `generic_const_exprs` separately as reasonable ways of handling constants in the type system
+                // completely fall apart under `generic_const_exprs` and makes this whole function Really hard to reason
+                // about if you have to consider gce whatsoever.
+                Some(ty::AnonConstKind::GCE) => {
+                    if uv.has_non_region_infer() || uv.has_non_region_param() {
+                        // `feature(generic_const_exprs)` causes anon consts to inherit all parent generics. This can cause
+                        // inference variables and generic parameters to show up in `ty::Const` even though the anon const
+                        // does not actually make use of them. We handle this case specially and attempt to evaluate anyway.
+                        match tcx.thir_abstract_const(uv.def) {
+                            Ok(Some(ct)) => {
+                                let ct = tcx.expand_abstract_consts(ct.instantiate(tcx, uv.args));
+                                if let Err(e) = ct.error_reported() {
+                                    return Err(EvaluateConstErr::EvaluationFailure(e));
+                                } else if ct.has_non_region_infer() || ct.has_non_region_param() {
+                                    // If the anon const *does* actually use generic parameters or inference variables from
+                                    // the generic arguments provided for it, then we should *not* attempt to evaluate it.
+                                    return Err(EvaluateConstErr::HasGenericsOrInfers);
+                                } else {
+                                    let args =
+                                        replace_param_and_infer_args_with_placeholder(tcx, uv.args);
+                                    let typing_env = infcx
+                                        .typing_env(tcx.erase_regions(param_env))
+                                        .with_post_analysis_normalized(tcx);
+                                    (args, typing_env)
+                                }
+                            }
+                            Err(_) | Ok(None) => {
+                                let args = GenericArgs::identity_for_item(tcx, uv.def);
+                                let typing_env = ty::TypingEnv::post_analysis(tcx, uv.def);
+                                (args, typing_env)
+                            }
                         }
+                    } else {
+                        let typing_env = infcx
+                            .typing_env(tcx.erase_regions(param_env))
+                            .with_post_analysis_normalized(tcx);
+                        (uv.args, typing_env)
                     }
-                    Err(_) | Ok(None) => {
-                        let args = GenericArgs::identity_for_item(tcx, uv.def);
-                        let typing_env = ty::TypingEnv::post_analysis(tcx, uv.def);
-                        (args, typing_env)
+                }
+                Some(ty::AnonConstKind::RepeatExprCount) => {
+                    if uv.has_non_region_infer() {
+                        // Diagnostics will sometimes replace the identity args of anon consts in
+                        // array repeat expr counts with inference variables so we have to handle this
+                        // even though it is not something we should ever actually encounter.
+                        //
+                        // Array repeat expr counts are allowed to syntactically use generic parameters
+                        // but must not actually depend on them in order to evalaute successfully. This means
+                        // that it is actually fine to evalaute them in their own environment rather than with
+                        // the actually provided generic arguments.
+                        tcx.dcx().delayed_bug("AnonConst with infer args but no error reported");
                     }
+
+                    // The generic args of repeat expr counts under `min_const_generics` are not supposed to
+                    // affect evaluation of the constant as this would make it a "truly" generic const arg.
+                    // To prevent this we discard all the generic arguments and evalaute with identity args
+                    // and in its own environment instead of the current environment we are normalizing in.
+                    let args = GenericArgs::identity_for_item(tcx, uv.def);
+                    let typing_env = ty::TypingEnv::post_analysis(tcx, uv.def);
+
+                    (args, typing_env)
+                }
+                _ => {
+                    // We are only dealing with "truly" generic/uninferred constants here:
+                    // - GCEConsts have been handled separately
+                    // - Repeat expr count back compat consts have also been handled separately
+                    // So we are free to simply defer evaluation here.
+                    //
+                    // FIXME: This assumes that `args` are normalized which is not necessarily true
+                    //
+                    // Const patterns are converted to type system constants before being
+                    // evaluated. However, we don't care about them here as pattern evaluation
+                    // logic does not go through type system normalization. If it did this would
+                    // be a backwards compatibility problem as we do not enforce "syntactic" non-
+                    // usage of generic parameters like we do here.
+                    if uv.args.has_non_region_param() || uv.args.has_non_region_infer() {
+                        return Err(EvaluateConstErr::HasGenericsOrInfers);
+                    }
+
+                    let typing_env = infcx
+                        .typing_env(tcx.erase_regions(param_env))
+                        .with_post_analysis_normalized(tcx);
+                    (uv.args, typing_env)
                 }
-            } else if tcx.def_kind(uv.def) == DefKind::AnonConst && uv.has_non_region_infer() {
-                // FIXME: remove this when `const_evaluatable_unchecked` is a hard error.
-                //
-                // Diagnostics will sometimes replace the identity args of anon consts in
-                // array repeat expr counts with inference variables so we have to handle this
-                // even though it is not something we should ever actually encounter.
-                //
-                // Array repeat expr counts are allowed to syntactically use generic parameters
-                // but must not actually depend on them in order to evalaute successfully. This means
-                // that it is actually fine to evalaute them in their own environment rather than with
-                // the actually provided generic arguments.
-                tcx.dcx().delayed_bug(
-                    "Encountered anon const with inference variable args but no error reported",
-                );
-
-                let args = GenericArgs::identity_for_item(tcx, uv.def);
-                let typing_env = ty::TypingEnv::post_analysis(tcx, uv.def);
-                (args, typing_env)
-            } else {
-                // FIXME: This codepath is reachable under `associated_const_equality` and in the
-                // future will be reachable by `min_generic_const_args`. We should handle inference
-                // variables and generic parameters properly instead of doing nothing.
-                let typing_env = infcx
-                    .typing_env(tcx.erase_regions(param_env))
-                    .with_post_analysis_normalized(tcx);
-                (uv.args, typing_env)
             };
-            let uv = ty::UnevaluatedConst::new(uv.def, args);
 
+            let uv = ty::UnevaluatedConst::new(uv.def, args);
             let erased_uv = tcx.erase_regions(uv);
+
             use rustc_middle::mir::interpret::ErrorHandled;
             match tcx.const_eval_resolve_for_typeck(typing_env, erased_uv, DUMMY_SP) {
                 Ok(Ok(val)) => Ok(ty::Const::new_value(
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index ca58da5ca6d..ed0f34b5aa9 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -378,6 +378,7 @@ pub(super) fn opt_normalize_projection_term<'a, 'b, 'tcx>(
             term: projected_term,
             obligations: mut projected_obligations,
         })) => {
+            debug!("opt_normalize_projection_type: progress");
             // if projection succeeded, then what we get out of this
             // is also non-normalized (consider: it was derived from
             // an impl, where-clause etc) and hence we must
@@ -408,6 +409,7 @@ pub(super) fn opt_normalize_projection_term<'a, 'b, 'tcx>(
             Ok(Some(result.value))
         }
         Ok(Projected::NoProgress(projected_ty)) => {
+            debug!("opt_normalize_projection_type: no progress");
             let result =
                 Normalized { value: projected_ty, obligations: PredicateObligations::new() };
             infcx.inner.borrow_mut().projection_cache().insert_term(cache_key, result.clone());
@@ -621,8 +623,17 @@ struct Progress<'tcx> {
 }
 
 impl<'tcx> Progress<'tcx> {
-    fn error(tcx: TyCtxt<'tcx>, guar: ErrorGuaranteed) -> Self {
-        Progress { term: Ty::new_error(tcx, guar).into(), obligations: PredicateObligations::new() }
+    fn error_for_term(
+        tcx: TyCtxt<'tcx>,
+        alias_term: ty::AliasTerm<'tcx>,
+        guar: ErrorGuaranteed,
+    ) -> Self {
+        let err_term = if alias_term.kind(tcx).is_type() {
+            Ty::new_error(tcx, guar).into()
+        } else {
+            ty::Const::new_error(tcx, guar).into()
+        };
+        Progress { term: err_term, obligations: PredicateObligations::new() }
     }
 
     fn with_addl_obligations(mut self, mut obligations: PredicateObligations<'tcx>) -> Self {
@@ -650,7 +661,11 @@ fn project<'cx, 'tcx>(
     }
 
     if let Err(guar) = obligation.predicate.error_reported() {
-        return Ok(Projected::Progress(Progress::error(selcx.tcx(), guar)));
+        return Ok(Projected::Progress(Progress::error_for_term(
+            selcx.tcx(),
+            obligation.predicate,
+            guar,
+        )));
     }
 
     let mut candidates = ProjectionCandidateSet::None;
@@ -1965,7 +1980,13 @@ fn confirm_impl_candidate<'cx, 'tcx>(
     let param_env = obligation.param_env;
     let assoc_term = match specialization_graph::assoc_def(tcx, impl_def_id, assoc_item_id) {
         Ok(assoc_term) => assoc_term,
-        Err(guar) => return Ok(Projected::Progress(Progress::error(tcx, guar))),
+        Err(guar) => {
+            return Ok(Projected::Progress(Progress::error_for_term(
+                tcx,
+                obligation.predicate,
+                guar,
+            )));
+        }
     };
 
     // This means that the impl is missing a definition for the
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 44a76f6e083..2be799735a8 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -265,9 +265,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         &mut self,
         obligation: &PolyTraitObligation<'tcx>,
     ) -> SelectionResult<'tcx, Selection<'tcx>> {
-        if self.infcx.next_trait_solver() {
-            return self.infcx.select_in_new_trait_solver(obligation);
-        }
+        assert!(!self.infcx.next_trait_solver());
 
         let candidate = match self.select_from_obligation(obligation) {
             Err(SelectionError::Overflow(OverflowError::Canonical)) => {
@@ -299,6 +297,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         &mut self,
         obligation: &TraitObligation<'tcx>,
     ) -> SelectionResult<'tcx, Selection<'tcx>> {
+        if self.infcx.next_trait_solver() {
+            return self.infcx.select_in_new_trait_solver(obligation);
+        }
+
         self.poly_select(&Obligation {
             cause: obligation.cause.clone(),
             param_env: obligation.param_env,
@@ -2866,7 +2868,7 @@ fn rebind_coroutine_witness_types<'tcx>(
     let shifted_coroutine_types =
         tcx.shift_bound_var_indices(bound_vars.len(), bound_coroutine_types.skip_binder());
     ty::Binder::bind_with_vars(
-        ty::EarlyBinder::bind(shifted_coroutine_types.to_vec()).instantiate(tcx, args),
+        ty::EarlyBinder::bind(shifted_coroutine_types.types.to_vec()).instantiate(tcx, args),
         tcx.mk_bound_variable_kinds_from_iter(
             bound_vars.iter().chain(bound_coroutine_types.bound_vars()),
         ),