a failure to infer :consistent

[nsajko]

Minimal reproducer for both nightly and v1.11:

struct A{X} end
struct B{X, Y <: A{X}} end
f() = Val{B{X, A{X}} where {X}}()
Base.infer_effects(f, Tuple{})  # not consistent

Just removing the constraint on a struct type parameter makes effect inference work fine:

struct A{X} end
struct B{X, Y} end
f() = Val{B{X, A{X}} where {X}}()
Base.infer_effects(f, Tuple{})  # consistent

Is this behavior suboptimal, or is there some nonobvious reason why it is required for correctness?

[nsajko]

Another one:

struct A{X} end
struct B{X, Y <: A{X}, Z} end 
f() = Val{B{Int, A{Int}, Z} where {Z}}() 
Base.infer_effects(f, Tuple{})  # not consistent

Funny thing is, Val{B{Int, A{Int}, Z} where {Z}}() === Val{B{Int, A{Int}}}(), but this infers as consistent: f() = Val{B{Int, A{Int}}}().