eltype of BroadcastQuasiArray sometimes falls back to Any

[jagot]

When I want a BroadcastQuasiArray corresponding to a constant function, I do

julia> x = Inclusion(0.0..1.0)
Inclusion(0.0..1.0)

julia> (x -> 1).(x)
QuasiArrays.BroadcastQuasiArray{Int64,1,var"#319#320",Tuple{Inclusion{Float64,Interval{:closed,:closed,Float64}}}}(var"#319#320"(), (Inclusion(0.0..1.0),))

which rightly has an eltype of Int. Likewise, if I explicitly state another type, it also works:

julia> (x -> one(ComplexF64)).(x)
QuasiArrays.BroadcastQuasiArray{Complex{Float64},1,var"#317#318",Tuple{Inclusion{Float64,Interval{:closed,:closed,Float64}}}}(var"#317#318"(), (Inclusion(0.0..1.0),))

However, if the type happens to be stored in a variable, I get Any back:

julia> T = ComplexF64
Complex{Float64}

julia> (x -> one(T)).(x)
QuasiArrays.BroadcastQuasiArray{Any,1,var"#321#322",Tuple{Inclusion{Float64,Interval{:closed,:closed,Float64}}}}(var"#321#322"(), (Inclusion(0.0..1.0),))

Is this easily fixable, or is there a different syntax I should use to avoid type inference ambiguities?

[dlfivefifty]

That’s type unstable, try making T constant?

[jagot]

Fair enough :) but I'm trying to write tests for CompactBases.jl where I test both real and complex broadcasts. Maybe I rethink how I set those up.

[dlfivefifty]

Just be explicit? BroadcastQuasiArray{T}(x -> one(T), x)

[jagot]

That's a MethodError:

julia> T = ComplexF64
Complex{Float64}

julia> x = Inclusion(0.0..1.0)
Inclusion(0.0..1.0)

julia> o = BroadcastQuasiArray{T}(x -> one(T), x)
ERROR: MethodError: no method matching BroadcastQuasiArray{Complex{Float64},N,F,Args} where Args where F where N(::var"#1215#1216", ::Inclusion{Float64,Interval{:closed,:closed,Float64}})
Stacktrace:
 [1] top-level scope at REPL[42]:1
 [2] eval(::Module, ::Any) at ./boot.jl:331
 [3] eval_user_input(::Any, ::REPL.REPLBackend) at /Users/julia/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.4/REPL/src/REPL.jl:86
 [4] run_backend(::REPL.REPLBackend) at /Users/jagot/.julia/packages/Revise/tV8FE/src/Revise.jl:1165
 [5] top-level scope at REPL[1]:0

julia> o = BroadcastQuasiArray{T}(broadcasted(x -> one(T), x))
ERROR: MethodError: no method matching BroadcastQuasiArray{Complex{Float64},N,F,Args} where Args where F where N(::Base.Broadcast.Broadcasted{QuasiArrays.LazyQuasiArrayStyle{1},Nothing,var"#1217#1218",Tuple{Inclusion{Float64,Interval{:closed,:closed,Float64}}}})
Closest candidates are:
  BroadcastQuasiArray{Complex{Float64},N,F,Args} where Args where F where N(::Base.Broadcast.Broadcasted{#s31,#s30,#s29,#s28} where #s28<:Tuple where #s29 where #s30<:Tuple{Vararg{Any,N}} where #s31<:Union{Nothing, Base.Broadcast.BroadcastStyle}) where {T, N} at /Users/jagot/.julia/packages/QuasiArrays/3FYr1/src/lazyquasiarrays.jl:111
Stacktrace:
 [1] top-level scope at REPL[43]:1
 [2] eval(::Module, ::Any) at ./boot.jl:331
 [3] eval_user_input(::Any, ::REPL.REPLBackend) at /Users/julia/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.4/REPL/src/REPL.jl:86
 [4] run_backend(::REPL.REPLBackend) at /Users/jagot/.julia/packages/Revise/tV8FE/src/Revise.jl:1165
 [5] top-level scope at REPL[1]:0

[dlfivefifty]

Ah ok so we should add that