Inference error in Julia 1.8

[fredrikekre]

Found in PkgEval:

using Test, Tensors

function Ψ(C)
    μ = 1e10
    Kb = 1.66e11
    detC = det(C)
    J = sqrt(detC)
    Ĉ = detC^(-1/3)*C
    return 1/2*(μ * (tr(Ĉ)- 3) + Kb*(J-1)^2)
end

const F = one(Tensor{2,2}) + rand(Tensor{2,2})
const C = tdot(F)

@inferred hessian(Ψ, C)

git bisects points to JuliaLang/julia@e3b681c (cc @aviatesk if you have time to have a look).

e3b681c6872d87d74db63dd7ec3da2beee8e3ae4 is the first bad commit
commit e3b681c6872d87d74db63dd7ec3da2beee8e3ae4
Author: Shuhei Kadowaki <40514306+aviatesk@users.noreply.github.com>
Date:   Wed Feb 2 10:39:19 2022 +0900

    inference: always use const-prop'ed result (#44001)
    
    Previously, for `invoke`/opaque closure callsite, we use constant-prop'ed
    method body only when the inferred return type gets strictly improved
    by const-prop. But since the inliner is now able to inline the method
    body from `InferenceResult`, I believe it is always better to use method
    body shaped up by const-prop' no matter if the return type is improved
    (as we already do for ordinal call sites).
    
    > use constant prop' result even when the return type doesn't get refined
    ```julia
    const Gx = Ref{Any}()
    Base.@constprop :aggressive function conditional_escape!(cnd, x)
        if cnd
            Gx[] = x
        end
        return nothing
    end
    @test fully_eliminated((String,)) do x
        Base.@invoke conditional_escape!(false::Any, x::Any)
    end
    ```

:040000 040000 c48f5010124361b197808e99d69f5cd6d8327c73 e1c3e4c63b4c7128dbb0b4acae99ba864a580983 M     base
:040000 040000 5699d8a554ff36c25a94d4e2ed9576a2c6aab040 519f5968c110b456bbdab1b57015111630741106 M     test
bisect run success

[aviatesk]

Thanks, this is an interesting example. I will look into this later.

[aviatesk]

Ok, this can be closed now.

[fredrikekre]

Great, thank you!