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new solver proof tree generation #112351

Merged
merged 9 commits into from
Jun 19, 2023
Merged

new solver proof tree generation #112351

merged 9 commits into from
Jun 19, 2023

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BoxyUwU
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@BoxyUwU BoxyUwU commented Jun 6, 2023 •
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Adds a new -Z flag -Zdump-solver-proof-tree which causes us to generate proof trees for each call to infcx.evaluate_root_goal. Currently these just get debug!'d out rather than put in a file.

Callers of infcx.evaluate_root_goal get the proof tree returned to them and can force one to be generated by passing in GenerateProofTree::Yes. Currently we do not disable the global cache or do anything about the provisional cache when generating proof trees is enabled, this is optimal for debugging but not so much for diagnostics.

Personally I think the exact formatting of proof trees here is not ideal but it's easy to change after this PR lands and would like to avoid bikeshedding the exact way we output this before we even have any of the logic merged to get all the information out of the solver.

This PR is best reviewed with whitespace changes hidden, there is also probably no point going commit by commit

r? @lcnr

Below is the proof tree output for the AliasRelate(TAIT, sub, Alias) case in rust-lang/trait-system-refactor-initiative#25 from the following command:
RUSTC_LOG="rustc_trait_selection::solve::inspect::dump=debug" RUSTFLAGS="-Ztrait-solver=next -Zverbose -Zdump-solver-proof-tree" cargo +stage1 check

Proof tree 


DEBUG rustc_trait_selection::solve::inspect::dump tree=GOAL: Goal { predicate: Binder(AliasRelate(Term::Ty(Opaque(DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), [])), Subtype, Term::Ty(<?8t as std::iter::IntoIterator>::IntoIter)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(AliasRelate(Term::Ty(Opaque(DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), [])), Subtype, Term::Ty(<^1_0 as std::iter::IntoIterator>::IntoIter)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
    INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(AliasRelate(Term::Ty(Opaque(DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), [])), Subtype, Term::Ty(<?0t as std::iter::IntoIterator>::IntoIter)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [] }, PrivateZst)) }
        CANDIDATE normalizes-to: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
            TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
            REVISION 0
                GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}) }, Term::Ty(<^1_0 as std::iter::IntoIterator>::IntoIter)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                    INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}) }, Term::Ty(<?0t as std::iter::IntoIterator>::IntoIter)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [] }, PrivateZst)) }
                        TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                        REVISION 0
                            GOAL: Goal { predicate: Binder(TraitPredicate(<<?0t as std::iter::IntoIterator>::IntoIter as std::marker::Sized>, polarity:Positive), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                            CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(TraitPredicate(<<^1_0 as std::iter::IntoIterator>::IntoIter as std::marker::Sized>, polarity:Positive), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                            REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(TraitPredicate(<<?0t as std::iter::IntoIterator>::IntoIter as std::marker::Sized>, polarity:Positive), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }
                                    NORMALIZING SELF TY FOR ASSEMBLY:
                                        TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                        REVISION 0
                                            GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                            CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                            REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }
                                                    TRY_EVALUATE_ADDED_GOALS: Ok(Yes)
                                                    REVISION 0
                                            RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                        TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                        REVISION 0
                                            GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                            CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                            GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                    CANDIDATE constituent tys: Err(NoSolution)
                                    CANDIDATE assumption: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                        TRY_EVALUATE_ADDED_GOALS: Ok(Yes)
                                        REVISION 0
                            RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                            GOAL: Goal { predicate: Binder(TraitPredicate(<<?0t as std::iter::IntoIterator>::IntoIter as std::iter::Iterator>, polarity:Positive), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                            CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(TraitPredicate(<<^1_0 as std::iter::IntoIterator>::IntoIter as std::iter::Iterator>, polarity:Positive), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                            REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(TraitPredicate(<<?0t as std::iter::IntoIterator>::IntoIter as std::iter::Iterator>, polarity:Positive), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }
                                    NORMALIZING SELF TY FOR ASSEMBLY:
                                        TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                        REVISION 0
                                            GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                            CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                            GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                        TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                        REVISION 0
                                            GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                            CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                            GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                    CANDIDATE assumption: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                        TRY_EVALUATE_ADDED_GOALS: Ok(Yes)
                                        REVISION 0
                            RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                            GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [<?0t as std::iter::IntoIterator>::IntoIter], def_id: DefId(2:7319 ~ core[b962]::iter::traits::iterator::Iterator::Item) }, Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                            CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [<^1_0 as std::iter::IntoIterator>::IntoIter], def_id: DefId(2:7319 ~ core[b962]::iter::traits::iterator::Iterator::Item) }, Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                            REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [(OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [<?0t as std::iter::IntoIterator>::IntoIter], def_id: DefId(2:7319 ~ core[b962]::iter::traits::iterator::Iterator::Item) }, Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }
                                    TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                    REVISION 0
                                        NORMALIZES-TO HACK GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [<?0t as std::iter::IntoIterator>::IntoIter], def_id: DefId(2:7319 ~ core[b962]::iter::traits::iterator::Iterator::Item) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                        CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [<^1_0 as std::iter::IntoIterator>::IntoIter], def_id: DefId(2:7319 ~ core[b962]::iter::traits::iterator::Iterator::Item) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                        REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, <^0 as std::iter::IntoIterator>::Item] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                            INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [<?0t as std::iter::IntoIterator>::IntoIter], def_id: DefId(2:7319 ~ core[b962]::iter::traits::iterator::Iterator::Item) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }
                                                NORMALIZING SELF TY FOR ASSEMBLY:
                                                    TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                                    REVISION 0
                                                        GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?2t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                                        CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                                        GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                    TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                                    REVISION 0
                                                        GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?2t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                                        CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                                        GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                CANDIDATE assumption: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, <^0 as std::iter::IntoIterator>::Item] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                    TRY_EVALUATE_ADDED_GOALS: Ok(Yes)
                                                    REVISION 0
                                        RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, <^0 as std::iter::IntoIterator>::Item] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                        GOAL: Goal { predicate: Binder(AliasRelate(Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), [])), Equate, Term::Ty(<?0t as std::iter::IntoIterator>::Item)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                        CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(AliasRelate(Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), [])), Equate, Term::Ty(<^1_0 as std::iter::IntoIterator>::Item)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                        REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [(OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                            INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(AliasRelate(Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), [])), Equate, Term::Ty(<?0t as std::iter::IntoIterator>::Item)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }
                                                CANDIDATE normalizes-to: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [(OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                    TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                                    REVISION 0
                                                        GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}) }, Term::Ty(<?0t as std::iter::IntoIterator>::Item)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                                        CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}) }, Term::Ty(<^1_0 as std::iter::IntoIterator>::Item)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                                        REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [(OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                            INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}) }, Term::Ty(<?0t as std::iter::IntoIterator>::Item)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }
                                                                TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                                                REVISION 0
                                                                    GOAL: Goal { predicate: Binder(TraitPredicate(<<?0t as std::iter::IntoIterator>::Item as std::marker::Sized>, polarity:Positive), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                                                    CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(TraitPredicate(<<^1_0 as std::iter::IntoIterator>::Item as std::marker::Sized>, polarity:Positive), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                                                    REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                                        INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(TraitPredicate(<<?0t as std::iter::IntoIterator>::Item as std::marker::Sized>, polarity:Positive), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::Item)] }, PrivateZst)) }
                                                                            NORMALIZING SELF TY FOR ASSEMBLY:
                                                                                TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                                                                REVISION 0
                                                                                    GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                                                                    CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                                                                    REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                                                        INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::Item)] }, PrivateZst)) }
                                                                                            TRY_EVALUATE_ADDED_GOALS: Ok(Yes)
                                                                                            REVISION 0
                                                                                    RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                                                TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                                                                REVISION 0
                                                                                    GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                                                                    CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                                                                    GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                                            CANDIDATE constituent tys: Err(NoSolution)
                                                                            CANDIDATE assumption: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                                                TRY_EVALUATE_ADDED_GOALS: Ok(Yes)
                                                                                REVISION 0
                                                                    RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                                    GOAL: Goal { predicate: Binder(TraitPredicate(<<?0t as std::iter::IntoIterator>::Item as std::marker::Sized>, polarity:Positive), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                                                    CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(TraitPredicate(<<^1_0 as std::iter::IntoIterator>::Item as std::marker::Sized>, polarity:Positive), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                                                    GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                        RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [(OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                    REVISION 1
                                                        GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}) }, Term::Ty(<?0t as std::iter::IntoIterator>::Item)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                                        CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}) }, Term::Ty(<^1_0 as std::iter::IntoIterator>::Item)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                                        GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                CANDIDATE normalizes-to: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                    TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                                    REVISION 0
                                                        GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                                        CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                                        REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                            INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }
                                                                TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                                                REVISION 0
                                                                    NORMALIZES-TO HACK GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                                                    CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                                                    REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                                        INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }
                                                                            TRY_EVALUATE_ADDED_GOALS: Ok(Yes)
                                                                            REVISION 0
                                                                    RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                        RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                CANDIDATE substs relate: Err(NoSolution)
                                                CANDIDATE bidir normalizes-to: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [(OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                    TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                                    REVISION 0
                                                        GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}) }, Term::Ty(<?0t as std::iter::IntoIterator>::Item)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                                        CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}) }, Term::Ty(<^1_0 as std::iter::IntoIterator>::Item)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                                        GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [(OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                        GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                                        CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                                        REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                            INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::Item)] }, PrivateZst)) }
                                                                TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                                                REVISION 0
                                                                    NORMALIZES-TO HACK GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                                                    CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                                                    GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                        RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                    REVISION 1
                                                        GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}) }, Term::Ty(<?0t as std::iter::IntoIterator>::Item)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                                        CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}) }, Term::Ty(<^1_0 as std::iter::IntoIterator>::Item)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                                        GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                        GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                                        CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7203 ~ core[b962]::iter::traits::collect::IntoIterator::Item) }, Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                                        GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                        RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [(OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                    REVISION 1
                                        NORMALIZES-TO HACK GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [<?0t as std::iter::IntoIterator>::IntoIter], def_id: DefId(2:7319 ~ core[b962]::iter::traits::iterator::Iterator::Item) }, Term::Ty(?2t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                        CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [<^1_0 as std::iter::IntoIterator>::IntoIter], def_id: DefId(2:7319 ~ core[b962]::iter::traits::iterator::Iterator::Item) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                        REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, <^0 as std::iter::IntoIterator>::Item] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                            INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [<?0t as std::iter::IntoIterator>::IntoIter], def_id: DefId(2:7319 ~ core[b962]::iter::traits::iterator::Iterator::Item) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::Item)] }, PrivateZst)) }
                                                NORMALIZING SELF TY FOR ASSEMBLY:
                                                    TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                                    REVISION 0
                                                        GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?2t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                                        CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                                        REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                            INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::Item)] }, PrivateZst)) }
                                                                TRY_EVALUATE_ADDED_GOALS: Ok(Yes)
                                                                REVISION 0
                                                        RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                    TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                                    REVISION 0
                                                        GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?2t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                                        CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                                        GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                CANDIDATE assumption: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, <^0 as std::iter::IntoIterator>::Item] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                                    TRY_EVALUATE_ADDED_GOALS: Ok(Yes)
                                                    REVISION 0
                                        RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, <^0 as std::iter::IntoIterator>::Item] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                        GOAL: Goal { predicate: Binder(AliasRelate(Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), [])), Equate, Term::Ty(<?0t as std::iter::IntoIterator>::Item)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                        CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(AliasRelate(Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), [])), Equate, Term::Ty(<^1_0 as std::iter::IntoIterator>::Item)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                        GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                        GOAL: Goal { predicate: Binder(AliasRelate(Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), [])), Equate, Term::Ty(<?0t as std::iter::IntoIterator>::Item)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                        CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(AliasRelate(Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), [])), Equate, Term::Ty(<^1_0 as std::iter::IntoIterator>::Item)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                        GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                            RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [(OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                        REVISION 1
                            GOAL: Goal { predicate: Binder(TraitPredicate(<<?0t as std::iter::IntoIterator>::IntoIter as std::marker::Sized>, polarity:Positive), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                            CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(TraitPredicate(<<^1_0 as std::iter::IntoIterator>::IntoIter as std::marker::Sized>, polarity:Positive), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                            REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(TraitPredicate(<<?0t as std::iter::IntoIterator>::IntoIter as std::marker::Sized>, polarity:Positive), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::Item)] }, PrivateZst)) }
                                    NORMALIZING SELF TY FOR ASSEMBLY:
                                        TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                        REVISION 0
                                            GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                            CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                            GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                        TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                        REVISION 0
                                            GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                            CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                            GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                    CANDIDATE constituent tys: Err(NoSolution)
                                    CANDIDATE assumption: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                        TRY_EVALUATE_ADDED_GOALS: Ok(Yes)
                                        REVISION 0
                            RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                            GOAL: Goal { predicate: Binder(TraitPredicate(<<?0t as std::iter::IntoIterator>::IntoIter as std::iter::Iterator>, polarity:Positive), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                            CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(TraitPredicate(<<^1_0 as std::iter::IntoIterator>::IntoIter as std::iter::Iterator>, polarity:Positive), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                            REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(TraitPredicate(<<?0t as std::iter::IntoIterator>::IntoIter as std::iter::Iterator>, polarity:Positive), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::Item)] }, PrivateZst)) }
                                    NORMALIZING SELF TY FOR ASSEMBLY:
                                        TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                        REVISION 0
                                            GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                            CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                            GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                        TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                                        REVISION 0
                                            GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                                            CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                                            GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                    CANDIDATE assumption: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                                        TRY_EVALUATE_ADDED_GOALS: Ok(Yes)
                                        REVISION 0
                            RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                            GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [<?0t as std::iter::IntoIterator>::IntoIter], def_id: DefId(2:7319 ~ core[b962]::iter::traits::iterator::Iterator::Item) }, Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                            CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [<^1_0 as std::iter::IntoIterator>::IntoIter], def_id: DefId(2:7319 ~ core[b962]::iter::traits::iterator::Iterator::Item) }, Term::Ty(Opaque(DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                            GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
            REVISION 1
                GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}) }, Term::Ty(<^1_0 as std::iter::IntoIterator>::IntoIter)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
        CANDIDATE normalizes-to: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
            TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
            REVISION 0
                GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(Opaque(DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                    INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(Opaque(DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [] }, PrivateZst)) }
                        TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                        REVISION 0
                            NORMALIZES-TO HACK GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                            CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                            GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
        CANDIDATE substs relate: Err(NoSolution)
        CANDIDATE bidir normalizes-to: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
            TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
            REVISION 0
                GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}) }, Term::Ty(<^1_0 as std::iter::IntoIterator>::IntoIter)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?2t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(Opaque(DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                REVISION 0: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                    INSTANTIATED: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(Opaque(DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <?0t as std::iter::IntoIterator>::Item)] }, PrivateZst)) }
                        TRY_EVALUATE_ADDED_GOALS: Ok(Maybe(Ambiguity))
                        REVISION 0
                            NORMALIZES-TO HACK GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                            CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(^1_1)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }
                            GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0, ^1] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] })
                RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
            REVISION 1
                GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}) }, Term::Ty(?1t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [], def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}) }, Term::Ty(<^1_0 as std::iter::IntoIterator>::IntoIter)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
                GOAL: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [?0t], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(?2t)), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }
                CANONICALIZED: Canonical { value: QueryInput { goal: Goal { predicate: Binder(ProjectionPredicate(AliasTy { substs: [^1_0], def_id: DefId(2:7204 ~ core[b962]::iter::traits::collect::IntoIterator::IntoIter) }, Term::Ty(Opaque(DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), []))), []), param_env: ParamEnv { caller_bounds: [], reveal: UserFacing, constness: NotConst } }, anchor: Bind(DefId(0:6 ~ playground_proof_tree[b494]::a)), predefined_opaques_in_body: PredefinedOpaques(Interned(PredefinedOpaquesData { opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
                GLOBAL CACHE HIT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })
RESULT: Ok(Canonical { value: Response { certainty: Maybe(Ambiguity), var_values: CanonicalVarValues { var_values: [^0] }, external_constraints: ExternalConstraints(Interned(ExternalConstraintsData { region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, opaque_types: [(OpaqueTypeKey { def_id: DefId(0:8 ~ playground_proof_tree[b494]::Tait::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::IntoIter), (OpaqueTypeKey { def_id: DefId(0:9 ~ playground_proof_tree[b494]::Tait::{opaque#0}::{opaque#0}), substs: [] }, <^0 as std::iter::IntoIterator>::Item)] }, PrivateZst)) }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] })

@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. WG-trait-system-refactor The Rustc Trait System Refactor Initiative labels Jun 6, 2023
@BoxyUwU BoxyUwU force-pushed the proof_tree_generation branch 2 times, most recently from 858ba62 to 71244d7 Compare June 8, 2023 03:26
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@BoxyUwU BoxyUwU force-pushed the proof_tree_generation branch 3 times, most recently from 625c2ee to 2ce5c7e Compare June 8, 2023 18:24
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@BoxyUwU BoxyUwU marked this pull request as ready for review June 8, 2023 23:49
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rustbot commented Jun 8, 2023

Some changes occurred to the core trait solver

cc @rust-lang/initiative-trait-system-refactor

@BoxyUwU BoxyUwU force-pushed the proof_tree_generation branch 2 times, most recently from 4c2cc0e to 40353ab Compare June 16, 2023 15:04
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bors commented Jun 17, 2023

☔ The latest upstream changes (presumably #112716) made this pull request unmergeable. Please resolve the merge conflicts.

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lcnr commented Jun 19, 2023

have a bunch of nits but given that none of them change the general structure here, r=me after fixing the merge conflicts.

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lcnr commented Jun 19, 2023

this pretty much conflicts with everything which touches the trait solver, even just by renaming some shared types or whatever, so

@bors r+ rollup=never

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bors commented Jun 19, 2023

📌 Commit 3a6ce74 has been approved by lcnr

It is now in the queue for this repository.

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 19, 2023
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bors commented Jun 19, 2023

⌛ Testing commit 3a6ce74 with merge 18a6d91...

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bors commented Jun 19, 2023

☀️ Test successful - checks-actions
Approved by: lcnr
Pushing 18a6d91 to master...

@bors bors added the merged-by-bors This PR was explicitly merged by bors. label Jun 19, 2023
@bors bors merged commit 18a6d91 into rust-lang:master Jun 19, 2023
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@rustbot rustbot added this to the 1.72.0 milestone Jun 19, 2023
This was referenced Jun 19, 2023
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Finished benchmarking commit (18a6d91): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

mean range count
Regressions ❌
(primary)		 - - 0
Regressions ❌
(secondary)		 - - 0
Improvements ✅
(primary)		 -0.5% [-0.8%, -0.2%] 9
Improvements ✅
(secondary)		 -1.2% [-1.6%, -0.5%] 8
All ❌✅ (primary) -0.5% [-0.8%, -0.2%] 9

Max RSS (memory usage)

This benchmark run did not return any relevant results for this metric.

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

mean range count
Regressions ❌
(primary)		 - - 0
Regressions ❌
(secondary)		 - - 0
Improvements ✅
(primary)		 -0.8% [-0.8%, -0.8%] 1
Improvements ✅
(secondary)		 - - 0
All ❌✅ (primary) -0.8% [-0.8%, -0.8%] 1

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 657.557s -> 658.179s (0.09%)

@BoxyUwU BoxyUwU mentioned this pull request Jun 20, 2023
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