Both safe and wrong?

[ag0aep6g]

On 07.02.19 23:33, Luís Marques wrote:
> You are discussing evaluating the safety to the variable. Why not 
> evaluate the safety of the variable's initialization expression? That 
> is, @safe would always refer to code, just not necessarily functions.

Evaluating the safety of initializers without somehow marking the 
variables as @safe/@system would fix the issue you brought up, but not 
the one that Olivier is talking about.

His point is that you would still have to check manually if the globals 
you're using are safe or not. The compiler wouldn't see a difference 
between a safely initialized global and an unsafely initialized one.

But @safe is supposed to eliminate that kind of manual verification.

----
@safe:
int* x = /* ... this initializer would be checked for safety ... */;
void main()
{
     *x = 7; /* Guaranteed to be safe. */
     *y = 7; /* Might exhibit undefined behavior. */
}
@system:
int* y = /* ... this initializer would not be checked ... */;
----

If we'd apply the attributes to the variables, and forbid using @system 
variables in @safe code, then `*y = 7;` would be rejected.