More circulation check.

src/subtype.c

@@ -3237,7 +3237,9 @@ static jl_value_t *intersect(jl_value_t *x, jl_value_t *y, jl_stenv_t *e, int pa
                 }
                 if (!ccheck)
                     return jl_bottom_type;
-                if (var_occurs_inside(xub, (jl_tvar_t*)y, 0, 0) && var_occurs_inside(yub, (jl_tvar_t*)x, 0, 0)) {
+                if ((jl_has_typevar(xub, (jl_tvar_t*)y) || jl_has_typevar(xub, (jl_tvar_t*)x)) &&
+                    (jl_has_typevar(yub, (jl_tvar_t*)x) || jl_has_typevar(yub, (jl_tvar_t*)y))) {
+                    // TODO: This doesn't make much sense.
                     // circular constraint. the result will be Bottom, but in the meantime
                     // we need to avoid computing intersect(xub, yub) since it won't terminate.
                     return y;

test/subtype.jl

@@ -2320,12 +2320,23 @@ struct T48006{A1,A2,A3} end
                Tuple{T48006{F2, I, S2}, I} where {F2<:Real, I<:Int, S2<:Union{Int8, Val{F2}}},
                Tuple{T48006{Float64, Int, S1}, Int} where S1<:Union{Val{Float64}, Int8})
 
-
 f48167(::Type{Val{L2}}, ::Type{Union{Val{L1}, Set{R}}}) where {L1, R, L2<:L1} = 1
 f48167(::Type{Val{L1}}, ::Type{Union{Val{L2}, Set{R}}}) where {L1, R, L2<:L1} = 2
 f48167(::Type{Val{L}}, ::Type{Union{Val{L}, Set{R}}}) where {L, R} = 3
 @test f48167(Val{Nothing}, Union{Val{Nothing}, Set{Int}}) == 3
 
+# https://github.com/JuliaLang/julia/pull/31167#issuecomment-1358381818
+let S = Tuple{Type{T1}, T1, Val{T1}} where T1<:(Val{S1} where S1<:Val),
+    T = Tuple{Union{Type{T2}, Type{S2}}, Union{Val{T2}, Val{S2}}, Union{Val{T2}, S2}} where T2<:Val{A2} where A2 where S2<:Val
+    I1 = typeintersect(S, T)
+    I2 = typeintersect(T, S)
+    @test I1 !== Union{} && I2 !== Union{}
+    @test_broken I1 <: S
+    @test_broken I2 <: T
+    @test I2 <: S
+    @test_broken I2 <: T
+end
+
 @testset "known subtype/intersect issue" begin
     #issue 45874
     # Causes a hang due to jl_critical_error calling back into malloc...