Spec on casting to integer with smaller range than value

[Dennis]

On Saturday, 28 March 2020 at 16:06:39 UTC, kinke wrote:
> @safe is about memory corruption, not about disallowing any 
> undefined behavior.

The spec provides two definitions:

> Safe functions are functions that are statically checked to 
> exhibit no possibility of undefined behavior. Undefined 
> behavior is often used as a vector for malicious attacks.

https://dlang.org/spec/function.html#function-safety

> Memory Safety for a program is defined as it being impossible 
> for the program to corrupt memory. Therefore, the safe subset 
> of D consists only of programming language features that are 
> guaranteed to never result in memory corruption.

https://dlang.org/spec/memory-safe-d.html

Presence of undefined behavior is sufficient to cause memory 
corruption, and memory corruption itself is undefined behavior, 
so the definitions are equivalent and both describe the same 
thing.