Are there any feature test macros for the following?
- init-statement for if and while statements (P0614R1)
- init-statement for range-for (P0305R1)
I’m asking because I couldn’t find any reference to them in the C++20 draft
or in SD-6.
No, there are no feature test macros for those features. Generally we don't provide feature test macros in the case where you could use the "feature not available" version of the code unconditionally with no loss of functionality, which would generally be the case for these features.