DIP 1025--Dynamic Arrays Only Shrink, Never Grow--Community Review Round 1
schveiguy at gmail.com
Mon Nov 11 17:00:07 UTC 2019
On 11/11/19 11:47 AM, Uknown wrote:
> A lot of people are bringing it up, so I'll bite. The problem with @nogc
> is that it doesn't cover all cases. Imagine the code given in the DIP
> like this instead:
> void f(int x) @safe pure nothrow
> x ~= 0;
> void main() @safe
> import lib: f;
> import std.container : Array;
> Array!int x = [0, 1, 2, 3, 4];
> // x's dtor will try to free an invalid pointer
> Clearly here main does something that seems safe on the surface. But in
> actuality it is clearly unsafe code. And its hard to verify, because
> main and the libraries used are written by completely different people.
No, you are misunderstanding a lot here.
1. f(slice), there is no symbol slice, I think maybe you mean x?
2. f's x is a *copy*, which means that appending to x here DOES NOT
AFFECT main's x at all. Main's x will destroy perfectly fine, and all is
3. If @nogc is added to main, then it won't compile, because f cannot be
@nogc. Which is quite the point people are making.
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