The `__id__` method implemented in the C function has `MRB_ARGS_NONE()` specified, but it is also effective in the following cases.
```ruby
p nil.__id__ opts: 1 rescue p :a
p nil.method(:__id__).call 1 rescue p :b
p nil.method(:__id__).call opts: 1 rescue p :c
p nil.method(:__id__).to_proc.call 1 rescue p :d
p nil.method(:__id__).to_proc.call opts: 1 rescue p :e
p nil.method(:__id__).unbind.bind_call nil, 1 rescue p :f
p nil.method(:__id__).unbind.bind_call nil, opts: 1 rescue p :g
p nil.__send__ :__id__, 1 rescue p :h
p nil.__send__ :__id__, opts: 1 rescue p :i
```
After applying this patch, all items will output symbols in the same way as CRuby.
For this purpose, add `MRB_PROC_NOARG` to `struct RProc::flags`.
* The `Fixnum` constant is now an alias for the `Integer` class.
* Remove `struct mrb_state::fixnum_class` member.
If necessary, use `struct mrb_state::integer_class` instead.
Formerly, `__send__(*args)` modified `args` with `Array#shift`.
This bug affects optcarrot.
This changeset avoids the array destruction by using
`args = args[1, len-1]`.
We assume meta-programming is less used in embedded environments.
We have moved following methods:
* Kernel module
global_variables, local_variables, singleton_class,
instance_variables, instance_variables_defined?, instance_variable_get,
instance_variable_set, methods, private_methods, public_methods,
protected_methods, singleton_methods, define_singleton_methods
* Module class
class_variables, class_variables_defined?, class_variable_get,
class_variable_set, remove_class_variable, included_modules,
instance_methods, remove_method, method_removed, constants
* Module class methods
constants, nesting
Note:
Following meta-programming methods are kept in the core:
* Module class
alias_method, undef_method, ancestors, const_defined?, const_get,
const_set, remove_const, method_defined?, define_method
* Toplevel object
define_method
`mruby-metaprog` gem is linked by default (specified in default.gembox).
When it is removed, it will save 40KB (stripped:8KB) on x86-64
environment last time I measured.