assume, assert, enforce, @safe

[Walter Bright via Digitalmars-d]

On 7/31/2014 3:24 AM, ponce wrote:
> On Thursday, 31 July 2014 at 09:13:53 UTC, Walter Bright wrote:
>> On 7/31/2014 1:23 AM, Daniel Murphy wrote:
>>> "Walter Bright"  wrote in message news:lrbpvj$mih$1 at digitalmars.com...
>>>
>>>> 5. assert(0); is equivalent to a halt, and the compiler won't remove it.
>>>
>>> This is not the same definition the spec gives.  The spec says assert(0) can be
>>> treated as unreachable, and the compiler is allowed to optimize accordingly.
>>
>> It says more than that:
>>
>> "The expression assert(0) is a special case; it signifies that it is
>> unreachable code. Either AssertError is thrown at runtime if it is reachable,
>> or the execution is halted (on the x86 processor, a HLT instruction can be
>> used to halt execution). The optimization and code generation phases of
>> compilation may assume that it is unreachable code."
>>
>>   -- http://dlang.org/expression.html#AssertExpression
>
> You said "the compiler won't remove it".

Right, and it doesn't.

> http://dlang.org/expression.html#AssertExpression says: "The optimization and
> code generation phases of compilation may assume that it is unreachable code."
>
> Who is right?

It means if the control flow does actually get there, a HALT is executed.