With regards to RAII (as in constructors/destructors, not the stuff in the issue you linked), I think it simply didn't fit within Zig's goals. A big part of Zig is readability; what you read is what you get, and RAII is very much not that. Looking at a block of C++ code, there's no way to tell what happens unless you also know what the constructors/destructors of each data type in the block does.