int*[] foo;
foo.length = 5;

import std.c.string;
int* baz = cast(string*)malloc(50);

import std.c.stdio;
printf("%d %d", foo.length, baz.length );

prints:
Error: no property 'length' for type 'int*'

BUT:

string*[] foo;
foo.length = 5;

import std.c.string;
string* baz = cast(string*)malloc(50);

import std.c.stdio;
printf("%d %d", foo.length, baz.length );

compiles and prints:
5 -842150451

How come string* suddenly has a .length property?
Anyway the result is garbage, so I think this must be a bug.

DMD32 D Compiler v2.073.2

Random D user wrote:

> How come string* suddenly has a .length property?

due to automatic pointer dereferencing that `.` does. no, not a bug.

On Sunday, 12 March 2017 at 01:55:20 UTC, ketmar wrote:
> Random D user wrote:
>
>> How come string* suddenly has a .length property?
>
> due to automatic pointer dereferencing that `.` does. no, not a bug.

Ah... right. Silly me. Of course, since string is actually immutable(char)[].
That's bit of a nasty corner case where -> == . isn't that nice. Fortunately, it's rare.

Thanks.

This happened to me, when I was packing stuff into SoA layout and didn't want to duplicate the length in the struct (implicitly by using []). Of course, I forgot to update one place to use the shared length.
That is:

length
ptr
ptr
ptr

instead of

ptr
length
ptr
length
ptr
length

Perhaps I should do a SoA layout template that somehow disables .length on individual arrays.