Incorrect inference in MTK

[Keno]

Using Julia and MTK master:

using ModelingToolkit
using ModelingToolkit.BipartiteGraphs
graph = ModelingToolkit.BipartiteGraph(0, 0, Val(false))
f() = DiCMOBiGraph{true}(graph)

julia> @code_typed f()
CodeInfo(
1 ─ %1 = Main.graph::Any
│        (DiCMOBiGraph{true, I} where I)(%1)::Union{}
└──      unreachable
) => Union{}

julia> f()
Unreachable reached at 0x7f4edee39050

The inference of the constructor is incorrect. The function returns, causing the subsequent crash. I suspect an intersection issue of some sort as usual, but I will investigate further.

[Keno]

julia> TA = (@which DiCMOBiGraph{true}(graph)).sig
Tuple{Type{DiCMOBiGraph{Transposed, I} where I}, BipartiteGraph} where Transposed

julia> TB = Tuple{Type{DiCMOBiGraph{true}}, Any}
Tuple{Type{DiCMOBiGraph{true, I} where I}, Any}

julia> TC = Tuple{Type{DiCMOBiGraph{true}}, BipartiteGraph}
Tuple{Type{DiCMOBiGraph{true, I} where I}, BipartiteGraph}

julia> TC <: TA
true

julia> TC <: TB
true

julia> typeintersect(TA, TB)
Union{}

[Keno]

Non-MTK reduction:

mutable struct Foo{I<:Integer,B<:Union{Vector{Vector{I}},I}}
    ne::Int
    badjlist::B # `badjlist[dst] => srcs` or `ndsts`
end
Foo() = Foo(0, 0)
foo = Foo()

struct Bar{Transposed, I, G<:Foo{I}}; end
Bar{Transposed}(g::Foo) where {Transposed} = Bar{Transposed, typeof(g).parameters[1], typeof(g)}()
f() = Bar{true}(foo)
f()

[Keno]

Also happens on 1.7. Haven't seen this in the wild yet with regular MTK usage, but that of course depends on inference to figure out the argument to this constructor.

[JeffBezanson]

1.0: works
1.1: stack overflow in intersection, aborting inference
1.2: this version of the bug introduced

[JeffBezanson]

Slightly smaller:

julia> struct X{A, I, B<:Union{Ref{I},I}}; end

julia> typeintersect(Tuple{X{T  }, Int} where T, Tuple{X{Int}, Any})
Union{}