Discussion Thread: DIP 1028--Make @safe the Default--Final Review

[rikki cattermole]

On 27/03/2020 12:16 PM, Jonathan M Davis wrote:
> On Thursday, March 26, 2020 4:54:53 PM MDT rikki cattermole via Digitalmars-
> d wrote:
>> And then there is .di files which complicates the matters further.
>>
>> But I agree with you.
>>
>> If the compiler _cannot_ or has _not_ confirmed it is @safe, a function
>> should not be marked as @safe and be callable.
> 
> Actually, .di files don't complicate things much. non-extern(D) declarations
> have to be treated the same no matter where they are, and anything with a
> function body in a .di file is the same as if it were in a .d file. The only
> real difference is that you then have extern(D) declarations added into the
> mix, and because whether they're @safe, @trusted, or @system is part of
> their name mangling, they cannot link if they don't have the same @safety
> level as the corresponding function definition (which was verified by the
> compiler if it's @safe). So, the compiler can treat extern(D) function
> declarations as @safe by default just like it does function definitions
> without there being a problem. The only real issue is if the declaration and
> definition don't match, which is a problem regardless of what the default
> @safety level is.
> 
> - Jonathan M Davis

The problem that concerns me is not its linkage or where that is 
occurring, its the fact that we treat .di files as trusted. We as a 
community have long said don't modify these files generated by the compiler.

If it is generated by the compiler then the checks that have been said 
to have occurred should have occurred. For example @safe on a function 
declaration without a body.

But on a regular D file, these checks have not been checked yet. As 
these files come from a human being and not a compiler. Hence if a body 
isn't present, it cannot be @safe. It has not been verified.

Which means that in a .d file what is allowed is less than a .di file.
If we follow this line of thought it creates a problematic situation.