On 03.01.2012 20:41, Andrew Wiley wrote:
On Tue, Jan 3, 2012 at 1:25 PM, simendsjo<[email protected]> wrote:
seems T[char[]] is rewritten as T[const(char)[]], and does not accept char[]
as key even if mutable data should automatically convert to const (right...?)
Shouldn't T[char[]] be disallowed, and have to be written as
T[immutable(char)[]] instead of a silent rewrite?
alias long[char[]] AA;
// key automatically changed to const(char)[]
static assert(is(AA == long[const(char)[]]));
AA aa;
aa["a"] = 10;
// error - have to use immutable keys
aa["b".dup] = 11;
By design, the problem is things like this:
char[] key = "somekey";
long[char[]] aa;
aa[key] = 5;
key[2] = 'b';
If this were allowed, the associative array would reach an invalid
state where the hash it stored for the key is no longer correct.
It does seem like T[char[]] should be disallowed and the requirement
for immutable keys should be literally enforced, and it's possible
that was intended but immutable/const weren't as complete when this
problem was last visited. I'll see if I can dig up an old discussion
about this.
It is disallowed, but it's enforced when setting a key rather than when
constructing the type.
So `aa[key] = 5` above fails as key is char[] rather than string.
