The GeneralPurposeAllocator will tell you about memory leaks and double frees in debug mode. Take a look at the example on the front page of ziglang.org.
That said, the main feature that Zig offers for avoiding those mistakes are defer and errdefer, those really go a long way in avoiding mistakes, while also keeping things simple and explicit, which also helps avoid bugs.
ArenaAllocator is another thing that helps with memory safety, depending on what you're doing.
Finally, having to pass an allocator explicitly to all the things that need to allocate also helps with that: if you have an allocator to a struct when initing it, then you know you will most probably have to call its deinit method once you don't need it anymore.
That said, the main feature that Zig offers for avoiding those mistakes are defer and errdefer, those really go a long way in avoiding mistakes, while also keeping things simple and explicit, which also helps avoid bugs.
ArenaAllocator is another thing that helps with memory safety, depending on what you're doing.
Finally, having to pass an allocator explicitly to all the things that need to allocate also helps with that: if you have an allocator to a struct when initing it, then you know you will most probably have to call its deinit method once you don't need it anymore.