I saw docs for std.experimental.allocator and also had found
automem library(https://code.dlang.org/packages/automem) for c++ style memory management via smartpointers.

From GC documentation std.experimental.allocator can not be used for:
    NewExpression
    Array appending
    Array concatenation
    Array literals (except when used to initialize static data)
    Associative array literals
    Any insertion, removal, or lookups in an associative array
    Extracting keys or values from an associative array
    Taking the address of (i.e. making a delegate to) a nested function that accesses variables in an outer scope
    A function literal that accesses variables in an outer scope
    An AssertExpression that fails its condition

Is that actual information? Does someone work to implement switch between gc and non-gc approach?

I learned for now automem's smartpointers which based on std.experimental.allocator can be used to store structs/classes.
Does automem(or std.experimental.allocator) has support for inherited classes,
polymorphism like std::unique_ptr<ISomeInterface> (or base class) in c++?

Does Phobos support std.experimental.allocator?

Are there another gotchas with "c++ like" memory management way in D?

P.S. Sorry for my bad english.