Will my variable be modified in a `do` block? Very subtle to anticipate

General Usage
,
12

So you make judgements with the source code of my my_dumb_fun. This is to say, the scope inference about the do block is much more difficult. (I am not aware what the source code of the Threads.lock function is).

Therefore, if the circumstance is like this, I cannot make a deterministic inference

julia> function modify_a_randomly(af)                                                                                        
           rand() > .5 && return                                                                                             
           af()                                                                                                              
       end;

julia> for i = 1:5
           a = -10i
           modify_a_randomly() do
               a = 10i
           end
           println("i = $i, a = $a")
       end
i = 1, a = 10
i = 2, a = -20
i = 3, a = 30
i = 4, a = -40
i = 5, a = 50