Function pointers/delegates default args were stealth removed?

[Maxim Fomin]

I think that D should be consistent with rules of types 
derivation, in particular the pointer one. Two pointer types 
should be same if and only if types they pointer are the same. 
Breaking this rule would result in language complexity.

In case when default arguments are part of the type, default 
arguments must be written in declaration of a function pointer, 
moreover function pointers with different default arguments would 
be different types. So, besides of getting convenient usage of a 
shorter function call a user would have carry a particular 
default value with every declaration/definition he writes. Also 
similar functions pointers with different default arguments would 
not be interchangeable because they are different types. I think 
that such constraints would make the proposal a net loss to D 
contribution.

Also, making default arguments a part of a definition would break 
C/C++ legacy rules which claim that a function is characterized 
by its return value and number, order and types of its 
parameters. Although, it not necessarily mean that this rule 
cannot be broken, but it at least requires strong reasons, 
however as it is discussed, the proposal would result in a 
unclear usage, increased language complexity, subtle bugs and 
implementation issues.