[BUG]: Variable of trivial type not destroyed by transferring ownership about mojo HOT 4 CLOSED

@lattner can you please take a look?

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I just saw that he provided an answer to my Discord question that I asked a few weeks ago (link - https://discord.com/channels/1087530497313357884/1190784717998538903/1196704091041185843).

As soon as new version of Mojo will be released I will check if this bug got fixed or not.

Thank you for your work.

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yes, there is a bug here. We are doing the right thing non-trivial types, but trivial types like pointer are not handled correctly. This should be a compile time error:

fn main():
    var array = Pointer[Int]()
    _ = array^          ## Consumes the array variable
    _ = array[2]       ## Should be invalid to use "array" because it is consumed (would also crash at runtime in this case)

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Ah, actually not. The real issue is that the transfer operation on a value of trivial type (like a pointer or integer) is actually a noop. It doesn't destroy the input value, because these things don't have copy constructors, move operators or the other stuff to track.

Thank you for filing this, this is pretty confusing. I filed the compiler to generate a warning to make this more clear:

x.mojo:4:14: warning: transfer from a value of trivial register type 'Pointer[Int, 0]' has no effect and can be removed
takePtr(array^)
                      ^

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