Why doesn't convert(Symbol, "foo") work?

Since the Symbol constructor works, is there a reason why convert(Symbol, "foo") shouldn’t work?

julia> Symbol("foo")
:foo

julia> convert(Symbol, "foo")
ERROR: MethodError: Cannot `convert` an object of type String to an object of type Symbol

convert happens automatically inside of the standard constructor.

julia> struct Foo
           a::Symbol
       end

julia> Foo("lion")
ERROR: MethodError: Cannot `convert` an object of type String to an object of type Symbol
Closest candidates are:
  convert(::Type{T}, ::T) where T at essentials.jl:171
  Symbol(::String) at boot.jl:436
  Symbol(::AbstractString) at strings/basic.jl:226
  ...
Stacktrace:
 [1] Foo(::String) at ./REPL[1]:2
 [2] top-level scope at REPL[2]:1

would work if convert was defined. Presumably, the Julia developers judged that conversion to/from strings should be done explicitly instead. I’m sure other language designers would have chosen otherwise, but personally I agree with the choice…

See also https://github.com/JuliaLang/julia/issues/39001