Weird inference failure in promote_u0 #918
Description
Originally opened in SciML/OrdinaryDiffEq.jl#2001
MWE:
using DiffEqBase
struct Thing
a::Float64
end
struct Wrapper1{T}
thing::T
end
struct Wrapper2{T}
thing::T
end
thing = Thing(1.0)
x = 1.0
DiffEqBase.promote_u0(x, Wrapper1(thing), (0.0, 1.0))
@code_warntype DiffEqBase.promote_u0(x, Wrapper1(thing), (0.0, 1.0))
DiffEqBase.promote_u0(x, Wrapper2(thing), (0.0, 1.0))
@code_warntype DiffEqBase.promote_u0(x, Wrapper2(thing), (0.0, 1.0))Output:
MethodInstance for DiffEqBase.promote_u0(::Float64, ::Wrapper1{Thing}, ::Tuple{Float64, Float64})
from promote_u0(u0, p, t0) @ DiffEqBase ~/.julia/packages/DiffEqBase/9rTlH/src/forwarddiff.jl:208
Arguments
#self#::Core.Const(DiffEqBase.promote_u0)
u0::Float64
p::Wrapper1{Thing}
t0::Tuple{Float64, Float64}
Locals
T::Any
Body::Any
1 ─ nothing
│ Core.NewvarNode(:(T))
│ %3 = DiffEqBase.eltype(u0)::Core.Const(Float64)
│ %4 = ForwardDiff.Dual::Core.Const(ForwardDiff.Dual)
│ %5 = (%3 <: %4)::Core.Const(false)
│ %6 = !%5::Core.Const(true)
└── goto #6 if not %6
2 ─ (T = DiffEqBase.anyeltypedual(p))
│ %9 = (T === DiffEqBase.Any)::Bool
└── goto #4 if not %9
3 ─ return u0
4 ─ %12 = T::Any
│ %13 = ForwardDiff.Dual::Core.Const(ForwardDiff.Dual)
│ %14 = (%12 <: %13)::Bool
└── goto #6 if not %14
5 ─ %16 = Base.broadcasted(T, u0)::Any
│ %17 = Base.materialize(%16)::Any
└── return %17
6 ┄ return u0
MethodInstance for DiffEqBase.promote_u0(::Float64, ::Wrapper2{Thing}, ::Tuple{Float64, Float64})
from promote_u0(u0, p, t0) @ DiffEqBase ~/.julia/packages/DiffEqBase/9rTlH/src/forwarddiff.jl:208
Arguments
#self#::Core.Const(DiffEqBase.promote_u0)
u0::Float64
p::Wrapper2{Thing}
t0::Tuple{Float64, Float64}
Locals
T::Type{Any}
Body::Float64
1 ─ nothing
│ Core.NewvarNode(:(T))
│ %3 = DiffEqBase.eltype(u0)::Core.Const(Float64)
│ %4 = ForwardDiff.Dual::Core.Const(ForwardDiff.Dual)
│ %5 = (%3 <: %4)::Core.Const(false)
│ %6 = !%5::Core.Const(true)
└── goto #5 if not %6
2 ─ (T = DiffEqBase.anyeltypedual(p))
│ %9 = (T::Core.Const(Any) === DiffEqBase.Any)::Core.Const(true)
└── goto #4 if not %9
3 ─ return u0
4 ─ Core.Const(:(T))
│ Core.Const(:(ForwardDiff.Dual))
│ Core.Const(:(%12 <: %13))
│ Core.Const(:(goto %19 if not %14))
│ Core.Const(:(Base.broadcasted(T, u0)))
│ Core.Const(:(Base.materialize(%16)))
└── Core.Const(:(return %17))
5 ┄ Core.Const(:(return u0))The first one always fails to infer (i.e. doing Wrapper2 first makes it fail to infer Wrapper2).
I have no idea why, since anyeltypedual seems to be const folded:
@code_warntype DiffEqBase.anyeltypedual(Wrapper1(thing))
@code_warntype DiffEqBase.anyeltypedual(Wrapper2(thing))
MethodInstance for DiffEqBase.anyeltypedual(::Wrapper1{Thing})
from anyeltypedual(x) @ DiffEqBase ~/.julia/packages/DiffEqBase/9rTlH/src/forwarddiff.jl:101
Arguments
#self#::Core.Const(DiffEqBase.anyeltypedual)
x::Wrapper1{Thing}
Body::Type{Any}
1 ─ %1 = (#self#)(x, 0)::Core.Const(Any)
└── return %1
MethodInstance for DiffEqBase.anyeltypedual(::Wrapper2{Thing})
from anyeltypedual(x) @ DiffEqBase ~/.julia/packages/DiffEqBase/9rTlH/src/forwarddiff.jl:101
Arguments
#self#::Core.Const(DiffEqBase.anyeltypedual)
x::Wrapper2{Thing}
Body::Type{Any}
1 ─ %1 = (#self#)(x, 0)::Core.Const(Any)
└── return %1