[Issue 11176] array.ptr in @safe code

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=11176

--- Comment #9 from Kenji Hara <k.hara...@gmail.com> ---
One another way I can think is, array.ptr property would add a hidden check
`arr.length != 0` under @safe code, then returns `null` instead when the length
is 0.

@safe ubyte* oops1(ubyte[] b) {
    return b.ptr;
}

@safe ubyte oops2(ubyte[] b) {
    return *b.ptr;
}

void main() {
    auto b = new ubyte[42];

    assert(oops1(b[0 .. $]) is &b[0]);
    assert(oops1(b[0 .. 1]) is &b[0]);

    assert(oops1(b[0 .. 0]) is null);   // the 'safer' behavior

    // With the proposed behavior, this call will cause null pointer
dereference,
    // then it's deterministic and does not cause undefined behavior.
    oops2(b[0 .. 0]);
}

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