Overflows in Phobos

[Walter Bright via Digitalmars-d]

On 7/27/2016 12:28 AM, Shachar Shemesh wrote:
> On 27/07/16 10:14, Walter Bright wrote:
>> Thank you. I'd prefer it to say something along the lines that it stops
>> execution at the assert(0) in an implementation-defined manner. This
>> leaves whether messages are printed or not, etc., up to the
>> implementation. I don't think the spec should require more than that
>> (for example, some uses may have no means to print an error message).
>
> I would ask that it at least be a "recommends". This message is muchu useful,
> and finding out it is not displayed in DMD release mode was a major disappointment.
>
> Updated proposed text:
> The expression assert(0) is a special case; it signifies code that should be
> unreachable. Either AssertError is thrown at runtime if reached or execution
> terminated. In the later case, it is recommended that the implementation print
> the assert message to stderr (or equivalent) before terminating. The
> optimization and code generation phases of the compilation may assume that any
> code after the assert(0) is unreachable.
>
> Shachar

Production of error messages is out of the purview of the core language 
specification, since it is highly dependent on the runtime environment, and the 
spec shouldn't get into Quality Of Implementation issues. Hence,

"The expression assert(0) is a special case; it signifies code that should be 
unreachable. If it is reached at runtime, either AssertError is thrown or 
execution is terminated in an implementation-defined manner. Any code after the 
assert(0) is considered unreachable."