Improving speed of runtime dispatch detector

General Usage Performance
20

Thanks.

Btw, I found a weird case of Julia’s specialization rules interfering with this interface:

using DispatchDoctor

@stable f(a, t::Type{T}) where {T} = sum(a; init=zero(T))

f([1f0, 1f0], Float32)

Despite the normal function being type stable, this actually fails the type specialization test

ERROR: TypeInstabilityError: Instability detected in function `f`
with arguments `(Vector{Float32}, DataType)`. Inferred to be 
`Any`, which is not a concrete type.
Stacktrace:
 [1] #_stable_wrap#1
   @ ~/PermaDocuments/DispatchDoctor.jl/src/DispatchDoctor.jl:25 [inlined]

because of Julia’s type specialization rules:

As a heuristic, Julia avoids automatically specializing on argument type parameters in three specific cases: Type, Function, and Vararg.

Even if I modify _stable_wrap to be

_stable_wrap(f::F, caller::G, args::Vararg{Any,N}; kwargs...) where {F,G,N}

it still fails, because now there are multiple non-specializing cases (Vararg and Type) – it seems like Julia lacks logic to deal with this situation.

I started a thread about this issue a while back:

but seems like that solution doesn’t work here.

Is there any way to force Julia to specialize no matter what?