`CompoundPeriod` uses dynamic dispatch

[charleskawczynski]

MWE

import JET, Dates
JET.@test_opt Dates.CompoundPeriod(Dates.Nanosecond(3e9))

Output

julia> JET.@test_opt Dates.CompoundPeriod(Dates.Nanosecond(3e9))
JET-test failed at REPL[15]:1
  Expression: #= REPL[15]:1 =# JET.@test_opt Dates.CompoundPeriod(Dates.Nanosecond(3.0e9))
  ═════ 17 possible errors found ═════
  ┌ Dates.CompoundPeriod(p::Dates.Nanosecond) @ Dates /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-HL2F7YQ3XH.0/build/default-honeycrisp-HL2F7YQ3XH-0/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/Dates/src/periods.jl:202
  │┌ Dates.CompoundPeriod(p::Vector{Dates.Period}) @ Dates /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-HL2F7YQ3XH.0/build/default-honeycrisp-HL2F7YQ3XH-0/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/Dates/src/periods.jl:141
  ││┌ kwcall(::@NamedTuple{rev::Bool, by::ComposedFunction{typeof(Dates.tons), typeof(oneunit)}}, ::typeof(sort!), v::Vector{Dates.Period}) @ Base.Sort ./sort.jl:1456
  │││┌ sort!(v::Vector{Dates.Period}; alg::Base.Sort.MissingOptimization{Base.Sort.BoolOptimization{Base.Sort.Small{10, Base.Sort.InsertionSortAlg, Base.Sort.IEEEFloatOptimization{Base.Sort.IsUIntMappable{Base.Sort.Small{40, Base.Sort.InsertionSortAlg, Base.Sort.CheckSorted{Base.Sort.ComputeExtrema{Base.Sort.ConsiderCountingSort{Base.Sort.CountingSort, Base.Sort.ConsiderRadixSort{Base.Sort.RadixSort, Base.Sort.Small{80, Base.Sort.InsertionSortAlg, Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}}}}}}}, Base.Sort.StableCheckSorted{Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}}}}}}}, lt::typeof(isless), by::ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, rev::Bool, order::Base.Order.ForwardOrdering, scratch::Nothing) @ Base.Sort ./sort.jl:1463
  ││││┌ _sort!(v::Vector{Dates.Period}, a::Base.Sort.MissingOptimization{Base.Sort.BoolOptimization{Base.Sort.Small{10, Base.Sort.InsertionSortAlg, Base.Sort.IEEEFloatOptimization{Base.Sort.IsUIntMappable{Base.Sort.Small{40, Base.Sort.InsertionSortAlg, Base.Sort.CheckSorted{Base.Sort.ComputeExtrema{Base.Sort.ConsiderCountingSort{Base.Sort.CountingSort, Base.Sort.ConsiderRadixSort{Base.Sort.RadixSort, Base.Sort.Small{80, Base.Sort.InsertionSortAlg, Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}}}}}}}, Base.Sort.StableCheckSorted{Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}}}}}}}, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, kw::@NamedTuple{scratch::Nothing}) @ Base.Sort ./sort.jl:636
  │││││┌ _sort!(v::Vector{Dates.Period}, a::Base.Sort.BoolOptimization{Base.Sort.Small{10, Base.Sort.InsertionSortAlg, Base.Sort.IEEEFloatOptimization{Base.Sort.IsUIntMappable{Base.Sort.Small{40, Base.Sort.InsertionSortAlg, Base.Sort.CheckSorted{Base.Sort.ComputeExtrema{Base.Sort.ConsiderCountingSort{Base.Sort.CountingSort, Base.Sort.ConsiderRadixSort{Base.Sort.RadixSort, Base.Sort.Small{80, Base.Sort.InsertionSortAlg, Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}}}}}}}, Base.Sort.StableCheckSorted{Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}}}}}}, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, kw::@NamedTuple{scratch::Nothing, lo::Int64, hi::Int64}) @ Base.Sort ./sort.jl:697
  ││││││┌ _sort!(v::Vector{Dates.Period}, a::Base.Sort.Small{10, Base.Sort.InsertionSortAlg, Base.Sort.IEEEFloatOptimization{Base.Sort.IsUIntMappable{Base.Sort.Small{40, Base.Sort.InsertionSortAlg, Base.Sort.CheckSorted{Base.Sort.ComputeExtrema{Base.Sort.ConsiderCountingSort{Base.Sort.CountingSort, Base.Sort.ConsiderRadixSort{Base.Sort.RadixSort, Base.Sort.Small{80, Base.Sort.InsertionSortAlg, Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}}}}}}}, Base.Sort.StableCheckSorted{Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}}}}}, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, kw::@NamedTuple{scratch::Nothing, lo::Int64, hi::Int64}) @ Base.Sort ./sort.jl:750
  │││││││┌ _sort!(v::Vector{Dates.Period}, ::Base.Sort.InsertionSortAlg, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, kw::@NamedTuple{scratch::Nothing, lo::Int64, hi::Int64}) @ Base.Sort ./sort.jl:785
  ││││││││┌ lt(o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, a::Dates.Period, b::Dates.Period) @ Base.Order ./ordering.jl:119
  │││││││││┌ (::ComposedFunction{typeof(Dates.tons), typeof(oneunit)})(x::Dates.Period) @ Base ./operators.jl:1041
  ││││││││││┌ (::ComposedFunction{typeof(Dates.tons), typeof(oneunit)})(x::Dates.Period; kw::@Kwargs{}) @ Base ./operators.jl:1041
  │││││││││││┌ call_composed(fs::Tuple{typeof(Dates.tons), typeof(oneunit)}, x::Tuple{Dates.Period}, kw::@Kwargs{}) @ Base ./operators.jl:1044
  ││││││││││││ runtime dispatch detected: Base.call_composed((oneunit,), x::Tuple{Dates.Period}, kw::@Kwargs{})::Any
  │││││││││││└────────────────────
  │││││││││││┌ call_composed(fs::Tuple{typeof(Dates.tons), typeof(oneunit)}, x::Tuple{Dates.Period}, kw::@Kwargs{}) @ Base ./operators.jl:1044
  ││││││││││││ runtime dispatch detected: tons(%1::Any)::Any
  │││││││││││└────────────────────
  │││││││┌ _sort!(v::Vector{Dates.Period}, ::Base.Sort.InsertionSortAlg, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, kw::@NamedTuple{scratch::Nothing, lo::Int64, hi::Int64}) @ Base.Sort ./sort.jl:785
  ││││││││ runtime dispatch detected: Base.Sort.lt(o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, %23::Dates.Period, %28::Dates.Period)::Any
  │││││││└────────────────────
  ││││││┌ _sort!(v::Vector{Dates.Period}, a::Base.Sort.Small{10, Base.Sort.InsertionSortAlg, Base.Sort.IEEEFloatOptimization{Base.Sort.IsUIntMappable{Base.Sort.Small{40, Base.Sort.InsertionSortAlg, Base.Sort.CheckSorted{Base.Sort.ComputeExtrema{Base.Sort.ConsiderCountingSort{Base.Sort.CountingSort, Base.Sort.ConsiderRadixSort{Base.Sort.RadixSort, Base.Sort.Small{80, Base.Sort.InsertionSortAlg, Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}}}}}}}, Base.Sort.StableCheckSorted{Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}}}}}, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, kw::@NamedTuple{scratch::Nothing, lo::Int64, hi::Int64}) @ Base.Sort ./sort.jl:752
  │││││││┌ _sort!(v::Vector{Dates.Period}, a::Base.Sort.IEEEFloatOptimization{Base.Sort.IsUIntMappable{Base.Sort.Small{40, Base.Sort.InsertionSortAlg, Base.Sort.CheckSorted{Base.Sort.ComputeExtrema{Base.Sort.ConsiderCountingSort{Base.Sort.CountingSort, Base.Sort.ConsiderRadixSort{Base.Sort.RadixSort, Base.Sort.Small{80, Base.Sort.InsertionSortAlg, Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}}}}}}}, Base.Sort.StableCheckSorted{Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}}}}, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, kw::@NamedTuple{scratch::Nothing, lo::Int64, hi::Int64}) @ Base.Sort ./sort.jl:681
  ││││││││┌ _sort!(v::Vector{Dates.Period}, a::Base.Sort.IsUIntMappable{Base.Sort.Small{40, Base.Sort.InsertionSortAlg, Base.Sort.CheckSorted{Base.Sort.ComputeExtrema{Base.Sort.ConsiderCountingSort{Base.Sort.CountingSort, Base.Sort.ConsiderRadixSort{Base.Sort.RadixSort, Base.Sort.Small{80, Base.Sort.InsertionSortAlg, Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}}}}}}}, Base.Sort.StableCheckSorted{Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}}}, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, kw::@NamedTuple{scratch::Nothing, lo::Int64, hi::Int64}) @ Base.Sort ./sort.jl:730
  │││││││││┌ _sort!(v::Vector{Dates.Period}, a::Base.Sort.StableCheckSorted{Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}}, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, kw::@NamedTuple{scratch::Nothing, lo::Int64, hi::Int64}) @ Base.Sort ./sort.jl:1123
  ││││││││││┌ _issorted(v::Vector{Dates.Period}, lo::Int64, hi::Int64, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}) @ Base.Sort ./sort.jl:1201
  │││││││││││ runtime dispatch detected: Base.Sort.lt(o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, %51::Dates.Period, %53::Dates.Period)::Any
  ││││││││││└────────────────────
  │││││││││┌ _sort!(v::Vector{Dates.Period}, a::Base.Sort.StableCheckSorted{Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}}, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, kw::@NamedTuple{scratch::Nothing, lo::Int64, hi::Int64}) @ Base.Sort ./sort.jl:1125
  ││││││││││┌ _issorted(v::Vector{Dates.Period}, lo::Int64, hi::Int64, o::Base.Order.Lt{Base.Sort.var"#26#27"{Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}}}) @ Base.Sort ./sort.jl:1201
  │││││││││││ runtime dispatch detected: Base.Sort.lt(o::Base.Order.Lt{Base.Sort.var"#26#27"{Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}}}, %51::Dates.Period, %53::Dates.Period)::Any
  ││││││││││└────────────────────
  │││││││││┌ _sort!(v::Vector{Dates.Period}, a::Base.Sort.StableCheckSorted{Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}}, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, kw::@NamedTuple{scratch::Nothing, lo::Int64, hi::Int64}) @ Base.Sort ./sort.jl:1131
  ││││││││││┌ _sort!(v::Vector{Dates.Period}, a::Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, kw::@NamedTuple{scratch::Nothing, lo::Int64, hi::Int64}) @ Base.Sort ./sort.jl:1063
  │││││││││││┌ _sort!(v::Vector{Dates.Period}, a::Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, kw::@NamedTuple{scratch::Nothing, lo::Int64, hi::Int64}; t::Nothing, offset::Nothing, swap::Bool, rev::Bool) @ Base.Sort ./sort.jl:1075
  ││││││││││││┌ partition!(t::Vector{Dates.Period}, lo::Int64, hi::Int64, offset::Int64, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, v::Vector{Dates.Period}, rev::Bool, pivot_dest::Vector{Dates.Period}, pivot_index_offset::Int64) @ Base.Sort ./sort.jl:1039
  │││││││││││││ runtime dispatch detected: Base.Sort.lt(o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, %43::Dates.Period, %38::Dates.Period)::Any
  ││││││││││││└────────────────────
  ││││││││││││┌ partition!(t::Vector{Dates.Period}, lo::Int64, hi::Int64, offset::Int64, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, v::Vector{Dates.Period}, rev::Bool, pivot_dest::Vector{Dates.Period}, pivot_index_offset::Int64) @ Base.Sort ./sort.jl:1039
  │││││││││││││ runtime dispatch detected: Base.Sort.:!(%45::Any)::Any
  ││││││││││││└────────────────────
  ││││││││││││┌ partition!(t::Vector{Dates.Period}, lo::Int64, hi::Int64, offset::Int64, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, v::Vector{Dates.Period}, rev::Bool, pivot_dest::Vector{Dates.Period}, pivot_index_offset::Int64) @ Base.Sort ./sort.jl:1039
  │││││││││││││ runtime dispatch detected: Base.Sort.lt(o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, %38::Dates.Period, %43::Dates.Period)::Any
  ││││││││││││└────────────────────
  ││││││││││││┌ partition!(t::Vector{Dates.Period}, lo::Int64, hi::Int64, offset::Int64, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, v::Vector{Dates.Period}, rev::Bool, pivot_dest::Vector{Dates.Period}, pivot_index_offset::Int64) @ Base.Sort ./sort.jl:1046
  │││││││││││││ runtime dispatch detected: Base.Sort.lt(o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, %38::Dates.Period, %67::Dates.Period)::Any
  ││││││││││││└────────────────────
  ││││││││││││┌ partition!(t::Vector{Dates.Period}, lo::Int64, hi::Int64, offset::Int64, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, v::Vector{Dates.Period}, rev::Bool, pivot_dest::Vector{Dates.Period}, pivot_index_offset::Int64) @ Base.Sort ./sort.jl:1046
  │││││││││││││ runtime dispatch detected: Base.Sort.lt(o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, %67::Dates.Period, %38::Dates.Period)::Any
  ││││││││││││└────────────────────
  ││││││││││││┌ partition!(t::Vector{Dates.Period}, lo::Int64, hi::Int64, offset::Int64, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, v::Vector{Dates.Period}, rev::Bool, pivot_dest::Vector{Dates.Period}, pivot_index_offset::Int64) @ Base.Sort ./sort.jl:1046
  │││││││││││││ runtime dispatch detected: Base.Sort.:!(%71::Any)::Any
  ││││││││││││└────────────────────
  │││││││││││┌ _sort!(v::Vector{Dates.Period}, a::Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, kw::@NamedTuple{scratch::Nothing, lo::Int64, hi::Int64}; t::Nothing, offset::Nothing, swap::Bool, rev::Bool) @ Base.Sort ./sort.jl:1094
  ││││││││││││┌ kwcall(::@NamedTuple{t::Vector{Dates.Period}, offset::Int64, swap::Bool, rev::Bool}, ::typeof(Base.Sort._sort!), v::Vector{Dates.Period}, a::Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, kw::@NamedTuple{scratch::Vector{Dates.Period}, lo::Int64, hi::Int64}) @ Base.Sort ./sort.jl:1063
  │││││││││││││┌ _sort!(v::Vector{Dates.Period}, a::Base.Sort.ScratchQuickSort{Missing, Missing, Base.Sort.InsertionSortAlg}, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, kw::@NamedTuple{scratch::Vector{Dates.Period}, lo::Int64, hi::Int64}; t::Vector{Dates.Period}, offset::Int64, swap::Bool, rev::Bool) @ Base.Sort ./sort.jl:1105
  ││││││││││││││┌ _sort!(v::Vector{Dates.Period}, ::Base.Sort.InsertionSortAlg, o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, kw::@NamedTuple{scratch::Vector{Dates.Period}, lo::Int64, hi::Int64}) @ Base.Sort ./sort.jl:785
  │││││││││││││││ runtime dispatch detected: Base.Sort.lt(o::Base.Order.By{ComposedFunction{typeof(Dates.tons), typeof(oneunit)}, Base.Order.ReverseOrdering{Base.Order.ForwardOrdering}}, %24::Dates.Period, %29::Dates.Period)::Any
  ││││││││││││││└────────────────────
  │┌ Dates.CompoundPeriod(p::Vector{Dates.Period}) @ Dates /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-HL2F7YQ3XH.0/build/default-honeycrisp-HL2F7YQ3XH-0/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/Dates/src/periods.jl:147
  ││ runtime dispatch detected: (%26::Dates.Period Dates.:+ %27::Dates.Period)::Any
  │└────────────────────
  │┌ Dates.CompoundPeriod(p::Vector{Dates.Period}) @ Dates /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-HL2F7YQ3XH.0/build/default-honeycrisp-HL2F7YQ3XH-0/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/Dates/src/periods.jl:147
  ││ runtime dispatch detected: ((p::Vector{Dates.Period})[%10::Int64] = %28::Any::Any)
  │└────────────────────
  │┌ Dates.CompoundPeriod(p::Vector{Dates.Period}) @ Dates /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-HL2F7YQ3XH.0/build/default-honeycrisp-HL2F7YQ3XH-0/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/Dates/src/periods.jl:150
  ││ runtime dispatch detected: Dates.iszero(%32::Dates.Period)::Any
  │└────────────────────
  │┌ Dates.CompoundPeriod(p::Vector{Dates.Period}) @ Dates /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-HL2F7YQ3XH.0/build/default-honeycrisp-HL2F7YQ3XH-0/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/Dates/src/periods.jl:150
  ││ runtime dispatch detected: Dates.:!(%33::Any)::Any
  │└────────────────────
  │┌ Dates.CompoundPeriod(p::Vector{Dates.Period}) @ Dates /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-HL2F7YQ3XH.0/build/default-honeycrisp-HL2F7YQ3XH-0/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/Dates/src/periods.jl:158
  ││ runtime dispatch detected: (%89::Any Dates.:(==) 0)::Any
  │└────────────────────
  
ERROR: There was an error during testing

[LilithHafner]

Type instability is when the output type of a function cannot be determined based on the input type. The CompoundPeriod constructor returns something of type CompoundPeriod (or errors) for all inputs so it is type stable. What you have found is dynamic dispatch which is due to the use of a container with abstract eltype. Specifically, the field of CompoundPeriod is:

julia/stdlib/Dates/src/periods.jl

Line 130 in 5b6a94d

periods::Vector{Period}

And pretty much any operation on the elements of a vector with abstract eltype will require dynamic dispatch.

[charleskawczynski]

To be fair, getindex(::Vector{Period}, ::Int) is type-unstable, and that appears in CompoundPeriod. So I would argue that CompoundPeriod (the method, not the type) is internally type-unstable.

[charleskawczynski]

But you're right that the root issue is the abstract eltype.