Another idiom I wish were gone from phobos/druntime

[deadalnix via Digitalmars-d]

On Thursday, 5 February 2015 at 01:07:56 UTC, Andrei Alexandrescu 
wrote:
> Yah, I agree "in" is useful for overridable functions. In fact 
> I'd say it's useful _only_ for overridable functions.
>

Putting the contract in the caller is not only useful for 
overridable functions.

1/ If a lib is compiled in without contract, but your code is 
compiled with, you get the in contract to run when you call 
library code, but not the assert within the function.

2/ The optimizer see the properties of the argument when they get 
to the in contract. This information is lost in the callee, 
unless inlining goes on. that means the amount of contract the 
optimizer can remove statically is greater with in contract.