apply_type_with_promotion

[jumerckx]

While in my testing traced_type now does the typevar promotion we talked about, it doesn't yet work for make_tracer as the result from traced_types isn't used to guide make_tracer AFAICT.

using Reactant

struct Bar{T}
    b::T
end
struct Foo{T, B<:Bar{T}, AT<:AbstractArray{T}}
    a::AT
    b::B
end

foo = Reactant.to_rarray(Foo(rand(3), Bar(1.)))

Reactant.traced_type(typeof(foo), Val(Reactant.ConcreteToTraced), Union{}, nothing, nothing)
# returns: Foo{Reactant.TracedRNumber{Float64}, Bar{Reactant.TracedRNumber{Float64}}, Reactant.TracedRArray{Float64, 1}}

Reactant.make_tracer(Reactant.OrderedIdDict(), foo, (), Reactant.ConcreteToTraced) # fails

ERROR: AssertionError: Could not recursively make tracer of object of type Foo{Float64, Bar{Float64}, ConcretePJRTArray{Float64, 1, 1, Reactant.Sharding.ShardInfo{Reactant.Sharding.NoSharding, Nothing}}} into Foo{Reactant.TracedRNumber{Float64}, Bar{Reactant.TracedRNumber{Float64}}, Reactant.TracedRArray{Float64, 1}} at field 2 (named b), need object of type Bar{Reactant.TracedRNumber{Float64}} found object of type Bar{Float64} 
Stacktrace:
 [1] make_tracer_unknown(seen::Reactant.OrderedIdDict{…}, prev::Any, path::Any, mode::Reactant.TraceMode; track_numbers::Type, sharding::Any, runtime::Any, kwargs::@Kwargs{})
   @ Reactant ~/Reactant2/src/Tracing.jl:1197
 [2] make_tracer_unknown
   @ ~/Reactant2/src/Tracing.jl:1095 [inlined]
 [3] #make_tracer#139
   @ ~/Reactant2/src/Tracing.jl:1232 [inlined]
 [4] make_tracer(seen::Reactant.OrderedIdDict{Any, Any}, prev::Any, path::Any, mode::Reactant.TraceMode)
   @ Reactant ~/Reactant2/src/Tracing.jl:1222
 [5] top-level scope
   @ ~/Reactant2/make_tracer_debuggin.jl:12
Some type information was truncated. Use `show(err)` to see complete types.

[wsmoses]

don't we still need to check below that the subtype matches, even if constrained? just to confirm we did do the typevar solve correctly?

[jumerckx]

I'm not sure...
The reason I added this early return is for e.g.:
Foo{Float64, Bar{Float64}, ConcretePJRTArray{Float64, 1}}
Which, with ConcreteToTraced is now converted to:
Foo{TracedRNumber{Float64}, Bar{TracedRNumber{Float64}}, TracedRArray{Float64, 1}}

The field b of the original type is Bar{Float64}. When tracing this, it just returns Bar{Float64} because of lack of constraints. So what should we compare the fieldtype against?

[wsmoses]

struct T
   d::Array
end

[wsmoses]

struct T{D<:Array}
   d::D
end


struct T{D<:AbstractArray{Float64}}
   d::D
end

[wsmoses]

check can be skipped when an unconstrained typevar

• must be skipped when that typevar is itself a dependency of another type. If this is true in any case, we need the fancy make_tracer
• may be run when that typevar is itself not a dependency of another type. If this is true in all cases, we don't need the upgrade

[wsmoses]

case where need to skip checj

struct MyNewArray{FT, N, D <: AbstractArray{FT, N}}
    data::D
    off::FT
end

[wsmoses]

can we add some tests?

[github-actions]

[JuliaFormatter] _{reported by reviewdog 🐶}

Suggested change

	struct Foo{T, B<:Bar{T}, AT<:AbstractArray{T}}
	struct Foo{T,B<:Bar{T},AT<:AbstractArray{T}}

[github-actions]

[JuliaFormatter] _{reported by reviewdog 🐶}

Suggested change

	@test Reactant.apply_type_with_promotion(Foo, [Float64, Bar{Float64}, Reactant.TracedRArray{Float64, 1}]) == Foo{
	@test Reactant.apply_type_with_promotion(
	Foo, [Float64, Bar{Float64}, Reactant.TracedRArray{Float64,1}]
	) == Foo{

[github-actions]

[JuliaFormatter] _{reported by reviewdog 🐶}

Suggested change

	Reactant.TracedRArray{Float64, 1},
	Reactant.TracedRArray{Float64,1},