trick to make throwing method @nogc

[ikod via Digitalmars-d-learn]

Hello,

I have a method for range:
struct Range {
    immutable(ubyte[]) _buffer;
    size_t             _pos;

    @property void popFront() pure @safe {
        enforce(_pos < _buffer.length, "popFront from empty 
buffer");
        _pos++;
    }
}

I'd like to have @nogc here, but I can't because enforce() is 
non-@nogc.
I have a trick but not sure if it is valid, especially I don't 
know if optimization will preserve code, used for throwing:

import std.string;

struct Range {
    immutable(ubyte[]) _buffer;
    size_t  _pos;

    this(immutable(ubyte[]) s) {
        _buffer = s;
    }
    @property void popFront() pure @safe @nogc {
        if (_pos >= _buffer.length ) {
            auto _ = _buffer[$]; // throws RangeError
        }
        _pos++;
    }
}

void main() {
        auto r = Range("1".representation);
        r.popFront();
        r.popFront(); // throws
}

Is it ok to use it? Is there any better solution?

Thanks!