[BUG] Aggressively consuming copied variables

[aaronalbers]

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The issue is that the last use detection of variables doesn't take into account loops. If the last use is detected inside a loop body it will apply std::move() and it will be consumed on the first iteration.

wreakit: (copy s: std::string) -> std::string = {
    wreak: std::string = "it";
    i: int = 0;
    while i < 2 next i++ {
        wreak = s;
    }
    return wreak;
}

Generates the code:

[[nodiscard]] auto wreakit(std::string s) -> std::string{
    std::string wreak { "it" }; 
    int i { 0 }; 
    for( ; i < 2; ++i ) {
        wreak = std::move(s);
    }
    return wreak; 
}

Expected value returned by wreakit("ralph"); would be "ralph" but actual value is "";