assume, assert, enforce, @safe

[David Bregman via Digitalmars-d]

On Wednesday, 30 July 2014 at 22:01:23 UTC, Walter Bright wrote:
> I'd like to sum up my position and intent on all this.
>
> 1. I can discern no useful, practical difference between the 
> notions of assume and assert.

People have explained the difference repeatedly, a ridiculous 
number of times now. Could you please take a minute to understand 
it this time instead of flippantly dismissing it again?

assert does a runtime check, assume does not
assume affects code generation/optimization, assert does not
assert is for debugging, assume is not
assume is for optimization, assert is not

In terms of what they practically do, they have *nothing* in 
common, their functions are entirely orthogonal.

Still think there is no practical difference?

> 2. The compiler can make use of assert expressions to improve 
> optimization, even in -release mode.

This will introduce a lot of undefined behavior, including making 
@safe code with asserts unsafe. I really think this needs to be 
acknowledged. As far as I can tell from the other thread, it 
still hasn't been.