Another idiom I wish were gone from phobos/druntime

[Jonathan Marler via Digitalmars-d]

On Thursday, 5 February 2015 at 00:42:01 UTC, Andrei Alexandrescu 
wrote:
> On 2/4/15 4:40 PM, Jonathan Marler wrote:
>> On Thursday, 5 February 2015 at 00:35:50 UTC, bearophile wrote:
>>> Contracts can be read by tools, and they are part of the 
>>> function
>>> signature. Contracts should be encouraged and increased, not 
>>> discouraged.
>>>
>>> Bye,
>>> bearophile
>>
>> Not to mention that contracts can be removed by the compiler 
>> at compile
>> time.
>
> Same about asserts. -- Andrei

Only if the function is inlined.  The function variables are 
unknown at compile time so there's no way for the function to 
compile it away (unless the optimizer can see every single call 
to the function).  If you make the caller responsible for the 
assert then it can determine whether or not it needs to perform 
it at runtime.

Then what about chaining contracts.  If a function has an out 
contract saying that the return value will be between a certain 
range, and you use that same variable in another function that 
requires it to be in the same range, you can compile away any 
assert after the first one. This is trivial to do with contracts. 
  You could do it without contracts I suppose, but would be much 
more brittle (every single return location would have to have the 
same assert for example)