Can someone please explain why the following assertion fails?

[Steven Schveighoffer via Digitalmars-d-learn]

On 10/31/16 3:24 PM, Ali Çehreli wrote:
> On 10/31/2016 12:08 PM, Gary Willoughby wrote:
>> Can someone please explain why the following assertion fails?
>>
>> import std.stdio;
>> import std.conv;
>>
>> void main(string[] args)
>> {
>>     auto x = 1;
>>
>>     assert(hashOf(x.to!(string)) == hashOf(x.to!(string)));
>> }
>>
>> Thanks.
>
> Because it considers the .ptr property of arrays as well:
>
>
> https://github.com/dlang/druntime/blob/master/src/core/internal/hash.d#L61
>
> //dynamic array hash
> size_t hashOf(T)(auto ref T val, size_t seed = 0)
> if (!is(T == enum) && !is(T : typeof(null)) && is(T S: S[]) &&
> !__traits(isStaticArray, T)
>     && !is(T == struct) && !is(T == class) && !is(T == union))
> {
>     alias ElementType = typeof(val[0]);
>     static if (is(ElementType == interface) || is(ElementType == class) ||
>                    ((is(ElementType == struct) || is(ElementType == union))
>                        && is(typeof(val[0].toHash()) == size_t)))
>     //class or interface array or struct array with toHash(); CTFE
> depend on toHash() method
>     {
>         size_t hash = seed;
>         foreach (o; val)
>         {
>             hash = hashOf(o, hash);
>         }
>         return hash;
>     }
>     else static if (is(typeof(toUbyte(val)) == const(ubyte)[]))
>     //ubyteble array (arithmetic types and structs without toHash) CTFE
> ready for arithmetic types and structs without reference fields
>     {
>         auto bytes = toUbyte(val);
>         return bytesHash(bytes.ptr, bytes.length, seed);    // <-- HERE

bytesHash shouldn't use the pointer value in any way, it should just use 
the pointer to look at the bytes.

-Steve