experimental
Where enabled, macro definitions are allowed.
Where enabled, macro definitions are allowed. Macro implementations and macro applications are unaffected; they can be used anywhere.
Why introduce the feature? Macros promise to make the language more regular, replacing ad-hoc language constructs with a general powerful abstraction capability that can express them. Macros are also a more disciplined and powerful replacement for compiler plugins.
Why control it? For their very power, macros can lead to code that is hard to debug and understand.
The experimental object contains features that have been recently added but have not been thoroughly tested in production yet.
Experimental features may undergo API changes in future releases, so production code should not rely on them.
Programmers are encouraged to try out experimental features and report any bugs or API inconsistencies they encounter so they can be improved in future releases.