Bug 20345 – writing through `void[]` cannot be @safe
Status
RESOLVED
Resolution
DUPLICATE
Severity
normal
Priority
P3
Component
dmd
Product
D
Version
D2
Platform
All
OS
All
Creation time
2019-11-01T10:57:19Z
Last change time
2024-10-04T12:51:39Z
Keywords
safe
Assigned to
No Owner
Creator
ag0aep6g
Comments
Comment #0 by ag0aep6g — 2019-11-01T10:57:19Z
Came up in the discussion of an "@system variables" DIP:
https://github.com/dlang/DIPs/pull/179#discussion_r341512564
A `void[]` might alias pointers so writing through it cannot be allowed in `@safe` code.
----
void main() @safe
{
int*[] p = [new int];
void[] v = p;
size_t[] x = [0xDEADBEEF];
v[] = x[]; /* Creates an invalid `int*`. Should be rejected. */
import std.stdio;
writeln(p[0]); /* Prints "DEADBEEF", i.e. `p[0]` is an invalid pointer. */
}
----