nameof(::UnionAll) does not perform constant folding.
julia> @code_typed nameof(Complex{Float32})
CodeInfo(
1 ─ return :Complex
) => Symbol
julia> @code_typed nameof(Complex)
CodeInfo(
1 ─ nothing::Nothing
2 ┄ %2 = φ (#1 => _2, #3 => %6)::Any
│ %3 = (%2 isa Base.UnionAll)::Bool
└── goto #4 if not %3
3 ─ %5 = π (%2, UnionAll)
│ %6 = Base.getfield(%5, :body)::Any
└── goto #2
4 ─ goto #5
5 ─ %9 = Base.nameof(%2)::Any
│ Core.typeassert(%9, Base.Symbol)::Symbol
│ %11 = π (%9, Symbol)
└── return %11
) => Symbol
At first I thought it was because @nospecialize was specified in Base.unwrap_unionall, but that doesn’t seem to be the case. Of course, the body field of UnionAll is boxed, so it should require special handling.
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