Why aren't function attributes inferred?

[Timon Gehr]

On 08/20/2011 06:50 PM, Sean Eskapp wrote:
> Since the compiler can clearly tell when a function is not const, safe, pure,
> or nothrow, why can't they just be assumed, unless proven otherwise?

This sort of inference is already done for function/delegate literals 
and template functions.

It is not done for other functions, because eg. their code is not 
necessarily available.

int foo(int x) pure; // how would you infer purity here?

Also, if normal functions would infer those attributes, they would be 
leaking implementation details all over the place. If a pure 
implementation would have to be changed to a non-pure one, all code that 
relied on the undocumented but inferred purity would break.