Ambiguities with Base

[jishnub]

julia> Test.detect_ambiguities(ChainRulesCore, Base)
16-element Vector{Tuple{Method, Method}}:
 (*(s, comp::Tangent) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differential_arithmetic.jl:168, *(comp::Tangent, s) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differential_arithmetic.jl:169)
 (==(a, b::AbstractThunk) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/thunks.jl:27, ==(::Missing, ::Any) in Base at missing.jl:75)
 (-(a::AbstractThunk, b) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/thunks.jl:30, -(a, b::AbstractThunk) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/thunks.jl:31)
 (/(z::AbstractZero, ::Any) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/abstract_zero.jl:25, /(a, b::AbstractThunk) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/thunks.jl:33)
 (ger!(alpha, x::AbstractThunk, y, A) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/thunks.jl:100, ger!(alpha, x, y::AbstractThunk, A) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/thunks.jl:103)
 (/(::Any, x::ChainRulesCore.NotImplemented) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/notimplemented.jl:43, /(a::AbstractThunk, b) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/thunks.jl:32)
 ((::ProjectTo{T, D} where D<:NamedTuple)(dx::AbstractZero) where T in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/projection.jl:127, (::ProjectTo{NoTangent, D} where D<:NamedTuple)(dx) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/projection.jl:135)
 (==(a::AbstractThunk, b) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/thunks.jl:26, ==(::Any, ::Missing) in Base at missing.jl:76)
 (/(z::AbstractZero, ::Any) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/abstract_zero.jl:25, /(::Any, x::ChainRulesCore.NotImplemented) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/notimplemented.jl:43)
 (==(a, b::AbstractThunk) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/thunks.jl:27, ==(w::WeakRef, v) in Base at gcutils.jl:4)
 (==(a::AbstractThunk, b) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/thunks.jl:26, ==(w, v::WeakRef) in Base at gcutils.jl:5)
 (/(a::AbstractThunk, b) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/thunks.jl:32, /(a, b::AbstractThunk) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/thunks.jl:33)
 ((::ProjectTo{T, D} where D<:NamedTuple)(dx::ChainRulesCore.NotImplemented) where T in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/projection.jl:128, (::ProjectTo{NoTangent, D} where D<:NamedTuple)(dx) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/projection.jl:135)
 ((project::ProjectTo{T, D} where D<:NamedTuple)(dx::Tangent) where T in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/projection.jl:75, (::ProjectTo{NoTangent, D} where D<:NamedTuple)(dx) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/projection.jl:135)
 (/(x::ChainRulesCore.NotImplemented, ::Any) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/notimplemented.jl:42, /(a, b::AbstractThunk) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/differentials/thunks.jl:33)
 ((project::ProjectTo)(dx::Thunk) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/projection.jl:131, (::ProjectTo{NoTangent, D} where D<:NamedTuple)(dx) in ChainRulesCore at /home/jishnu/.julia/packages/ChainRulesCore/Voykb/src/projection.jl:135)

[oxinabox]

Are any of these causing problems for you in practice?

[jishnub]

Not directly, but this leads to downstream test failures if a package checks for zero ambiguities without specifically excluding dependencies. This isn't a big issue as such, but would be nice to resolve this at some point.

[dlfivefifty]

This is triggering a test failure in DualNumbers.jl:

Test Failed at /home/runner/work/DualNumbers.jl/DualNumbers.jl/test/runtests.jl:4
94
  Expression: isempty(detect_ambiguities(DualNumbers, Base, Core))
95
   Evaluated: isempty(Tuple{Method, Method}[((::Type{T})(xs::ChainRulesCore.AbstractZero...) where T<:Number in ChainRulesCore at /home/runner/.julia/packages/ChainRulesCore/7ZiwT/src/tangent_types/abstract_zero.jl:28, Complex{T}(re, im) where T<:Real in Base at complex.jl:12), ((::Type{T})(xs::ChainRulesCore.AbstractZero...) where T<:Number in ChainRulesCore at /home/runner/.julia/packages/ChainRulesCore/7ZiwT/src/tangent_types/abstract_zero.jl:28, Dual{T}(value, epsilon) where T<:Union{Real, Complex} in DualNumbers at /home/runner/work/DualNumbers.jl/DualNumbers.jl/src/dual.jl:4), (==(a, b::ChainRulesCore.AbstractThunk) in ChainRulesCore at /home/runner/.julia/packages/ChainRulesCore/7ZiwT/src/tangent_types/thunks.jl:27, ==(::Missing, ::Any) in Base at missing.jl:75), (==(a::ChainRulesCore.AbstractThunk, b) in ChainRulesCore at /home/runner/.julia/packages/ChainRulesCore/7ZiwT/src/tangent_types/thunks.jl:26, ==(::Any, ::Missing) in Base at missing.jl:76), (==(a::ChainRulesCore.AbstractThunk, b) in ChainRulesCore at /home/runner/.julia/packages/ChainRulesCore/7ZiwT/src/tangent_types/thunks.jl:26, ==(w, v::WeakRef) in Base at gcutils.jl:5), (==(a, b::ChainRulesCore.AbstractThunk) in ChainRulesCore at /home/runner/.julia/packages/ChainRulesCore/7ZiwT/src/tangent_types/thunks.jl:27, ==(w::WeakRef, v) in Base at gcutils.jl:4)])

https://github.com/JuliaDiff/DualNumbers.jl/runs/4397702757?check_suite_focus=true

[oxinabox]

It is kinda annoying.
Like ambiguities that are never hit are not actually a problem; except that testing that way makes them a problem.
And keeping testing easy is important.
So we should resolve them.
So a PR to do so would be welcomed.
(and probably quite educational for the author to see how the tangent types work)

[dlfivefifty]

I just marked the test in DualNumbers as broken… I agree with you that the person who cares about it should fix it

[vtjnash]

Why is DualNumbers checking for ambiguities in Base (not with Base, which is implied by the DualNumbers argument, but actually in Base, because of the Base argument)?