julia> a = Base.AnnotatedString("abc", [(2:3, :x => 123)])
julia> av = view(a, 1:2)

# annotations present in both a and av...
julia> Base.annotations(a)
1-element Vector{Tuple{UnitRange{Int64}, Pair{Symbol, Any}}}:
 (2:3, :x => 123)

julia> Base.annotations(av)
1-element Vector{Tuple{UnitRange{Int64}, Pair{Symbol, Any}}}:
 (2:2, :x => 123)

# ... but not when putting them into an array
julia> Base.annotations.([a,av])
2-element Vector{Vector{Tuple{UnitRange{Int64}, Pair{Symbol, Any}}}}:
 [(2:3, :x => 123)]
 []

# regex matching preserves annotations...
julia> first(eachmatch(r"\w", a)).match |> Base.annotations
Tuple{UnitRange{Int64}, Pair{Symbol, Any}}[]

# ... but not always
julia> first(eachmatch(r"\w", av)).match |> Base.annotations
ERROR: MethodError: no method matching annotations(::SubString{String})

# and sometimes matching doesn't work at all:
julia> match(r"\w", av)
ERROR: ArgumentError: regex matching is only available for the String and AnnotatedString types; use String(s) to convert
# match() actually supports substrings, so I guess the error message is wrong?

# replace() works, but silently drops annotations:
julia> replace(a, a=>a) |> Base.annotations
ERROR: MethodError: no method matching annotations(::String)

# string multiplication preserves annotations,
julia> (a * av) |> Base.annotations
1-element Vector{Tuple{UnitRange{Int64}, Pair{Symbol, Any}}}:
 (2:3, :x => 123)

# join() does as well ...
julia> join([a, av]) |> Base.annotations
1-element Vector{Tuple{UnitRange{Int64}, Pair{Symbol, Any}}}:
 (2:3, :x => 123)

# ... but string concatenation doesn't
julia> string(a, av) |> Base.annotations
ERROR: MethodError: no method matching annotations(::String)

# interpolation also drops annotations:
julia> "x $a $av" |> Base.annotations
ERROR: MethodError: no method matching annotations(::String)