Fix type instability in convs using CompoundPeriod

[ronisbr]

The functions toms, tons, and days uses sum over a vector of Periods to obtain the conversion of a CompoundPeriod. However, the compiler cannot infer the return type because those functions can return either Int or Float depending on the type of the Period. This PR forces the result of those functions to be Float64, fixing the type stability.

Before this PR we had:

julia> using Dates

julia> p = Dates.Second(1) + Dates.Minute(1) + Dates.Year(1)
1 year, 1 minute, 1 second

julia> @code_warntype Dates.tons(p)
MethodInstance for Dates.tons(::Dates.CompoundPeriod)
  from tons(c::Dates.CompoundPeriod) @ Dates ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.12/Dates/src/periods.jl:458
Arguments
  #self#::Core.Const(Dates.tons)
  c::Dates.CompoundPeriod
Body::Any
1 ─ %1  = Dates.isempty::Core.Const(isempty)
│   %2  = Base.getproperty(c, :periods)::Vector{Period}
│   %3  = (%1)(%2)::Bool
└──       goto #3 if not %3
2 ─       return 0.0
3 ─ %6  = Dates.Float64::Core.Const(Float64)
│   %7  = Dates.sum::Core.Const(sum)
│   %8  = Dates.tons::Core.Const(Dates.tons)
│   %9  = Base.getproperty(c, :periods)::Vector{Period}
│   %10 = (%7)(%8, %9)::Any
│   %11 = (%6)(%10)::Any
└──       return %11


julia> @code_warntype Dates.toms(p)
MethodInstance for Dates.toms(::Dates.CompoundPeriod)
  from toms(c::Dates.CompoundPeriod) @ Dates ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.12/Dates/src/periods.jl:454
Arguments
  #self#::Core.Const(Dates.toms)
  c::Dates.CompoundPeriod
Body::Any
1 ─ %1  = Dates.isempty::Core.Const(isempty)
│   %2  = Base.getproperty(c, :periods)::Vector{Period}
│   %3  = (%1)(%2)::Bool
└──       goto #3 if not %3
2 ─       return 0.0
3 ─ %6  = Dates.Float64::Core.Const(Float64)
│   %7  = Dates.sum::Core.Const(sum)
│   %8  = Dates.toms::Core.Const(Dates.toms)
│   %9  = Base.getproperty(c, :periods)::Vector{Period}
│   %10 = (%7)(%8, %9)::Any
│   %11 = (%6)(%10)::Any
└──       return %11


julia> @code_warntype Dates.days(p)
MethodInstance for Dates.days(::Dates.CompoundPeriod)
  from days(c::Dates.CompoundPeriod) @ Dates ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.12/Dates/src/periods.jl:468
Arguments
  #self#::Core.Const(Dates.days)
  c::Dates.CompoundPeriod
Body::Any
1 ─ %1  = Dates.isempty::Core.Const(isempty)
│   %2  = Base.getproperty(c, :periods)::Vector{Period}
│   %3  = (%1)(%2)::Bool
└──       goto #3 if not %3
2 ─       return 0.0
3 ─ %6  = Dates.Float64::Core.Const(Float64)
│   %7  = Dates.sum::Core.Const(sum)
│   %8  = Dates.days::Core.Const(Dates.days)
│   %9  = Base.getproperty(c, :periods)::Vector{Period}
│   %10 = (%7)(%8, %9)::Any
│   %11 = (%6)(%10)::Any
└──       return %11

After this PR we have:

julia> using Dates

julia> p = Dates.Second(1) + Dates.Minute(1) + Dates.Year(1)
1 year, 1 minute, 1 second

julia> @code_warntype Dates.tons(p)
MethodInstance for Dates.tons(::Dates.CompoundPeriod)
  from tons(c::Dates.CompoundPeriod) @ Dates ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.12/Dates/src/periods.jl:458
Arguments
  #self#::Core.Const(Dates.tons)
  c::Dates.CompoundPeriod
Body::Float64
1 ─ %1  = Dates.isempty::Core.Const(isempty)
│   %2  = Base.getproperty(c, :periods)::Vector{Period}
│   %3  = (%1)(%2)::Bool
└──       goto #3 if not %3
2 ─       return 0.0
3 ─ %6  = Dates.Float64::Core.Const(Float64)
│   %7  = Dates.sum::Core.Const(sum)
│   %8  = Dates.tons::Core.Const(Dates.tons)
│   %9  = Base.getproperty(c, :periods)::Vector{Period}
│   %10 = (%7)(%8, %9)::Any
│   %11 = (%6)(%10)::Any
│   %12 = Dates.Float64::Core.Const(Float64)
│   %13 = Core.typeassert(%11, %12)::Float64
└──       return %13


julia> @code_warntype Dates.toms(p)
MethodInstance for Dates.toms(::Dates.CompoundPeriod)
  from toms(c::Dates.CompoundPeriod) @ Dates ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.12/Dates/src/periods.jl:454
Arguments
  #self#::Core.Const(Dates.toms)
  c::Dates.CompoundPeriod
Body::Float64
1 ─ %1  = Dates.isempty::Core.Const(isempty)
│   %2  = Base.getproperty(c, :periods)::Vector{Period}
│   %3  = (%1)(%2)::Bool
└──       goto #3 if not %3
2 ─       return 0.0
3 ─ %6  = Dates.Float64::Core.Const(Float64)
│   %7  = Dates.sum::Core.Const(sum)
│   %8  = Dates.toms::Core.Const(Dates.toms)
│   %9  = Base.getproperty(c, :periods)::Vector{Period}
│   %10 = (%7)(%8, %9)::Any
│   %11 = (%6)(%10)::Any
│   %12 = Dates.Float64::Core.Const(Float64)
│   %13 = Core.typeassert(%11, %12)::Float64
└──       return %13


julia> @code_warntype Dates.days(p)
MethodInstance for Dates.days(::Dates.CompoundPeriod)
  from days(c::Dates.CompoundPeriod) @ Dates ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.12/Dates/src/periods.jl:468
Arguments
  #self#::Core.Const(Dates.days)
  c::Dates.CompoundPeriod
Body::Float64
1 ─ %1  = Dates.isempty::Core.Const(isempty)
│   %2  = Base.getproperty(c, :periods)::Vector{Period}
│   %3  = (%1)(%2)::Bool
└──       goto #3 if not %3
2 ─       return 0.0
3 ─ %6  = Dates.Float64::Core.Const(Float64)
│   %7  = Dates.sum::Core.Const(sum)
│   %8  = Dates.days::Core.Const(Dates.days)
│   %9  = Base.getproperty(c, :periods)::Vector{Period}
│   %10 = (%7)(%8, %9)::Any
│   %11 = (%6)(%10)::Any
│   %12 = Dates.Float64::Core.Const(Float64)
│   %13 = Core.typeassert(%11, %12)::Float64
└──       return %13

[ronisbr]

Bump!

[ronisbr]

Bump 2!

[oscardssmith]

looks reasonable to me. (this likely didn't receive attention because everyone was busy with JuliaCon last week)

[aviatesk]

Thanks for your contribution, @ronisbr !