Eager finalization and smart pointers

Internals & Design Internals
5

This simplified example looks promising.

julia> n::Int = 0
0

julia> const safe_free = Base.@assume_effects :nothrow :notaskstate x->(global n += 1;Libc.free(x.ptr))
#3 (generic function with 1 method)

julia> mutable struct SafePointer
           ptr::Ptr{Int}
       end

julia> function f()
           for i in 1:100
               s = SafePointer(Libc.malloc(sizeof(Int)))
               finalizer(safe_free, s)
           end
           nothing
       end
f (generic function with 1 method)

julia> n
0

julia> f()

julia> n
100

Here is the documentation on the effects:

help?> Core.Compiler.Effects
  effects::Effects

  Represents computational effects of a method call.

  The effects are a composition of different effect bits that represent some program property of the method being analyzed. They are represented as Bool or UInt8 bits with the following meanings:

...

    •  nothrow::Bool: this method is guaranteed to not throw an exception.

...

    •  notaskstate::Bool: this method does not access any state bound to the current task and may thus be moved to a different task without changing observable behavior. Note that this currently implies that noyield as well, since yielding modifies the state of the current task, though this may be split in the future.
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