Some zig code and compileLog at the bottom showing some types

main.y.zig

const std = @import("std");
const warn = std.debug.warn;

fn Buffer(comptime buffer_size: usize) type {
    return struct {
        const Self = this;

        pub buffer: [buffer_size]u8,

        // Initialize if allocated in the stack
        pub fn initStack() Self {
            var self: Self = undefined;
            self.fill();
            @compileLog("initStack typeOf(Self): ", @typeOf(Self));
            @compileLog("initStack typeOf(self): ", @typeOf(self));
            @compileLog("initStack typeof(self.buffer): ", @typeOf(self.buffer));
            return self;
        }

        // Initialize if allocated in the heap
        pub fn initHeap(self: *Self) void {
            @compileLog("initHeap typeof(self): ", @typeOf(self));
            self.fill();
        }

        fn fill(self: *Self) void {
            @compileLog("fill typeof(self): ", @typeOf(self));
            for (self.buffer) |*ptr, i| {
                @compileLog("fill typeof(ptr):", @typeOf(ptr));
                @compileLog("fill typeof(ptr.*):", @typeOf(ptr.*));
                ptr.* = @truncate(u8, i);
            }
        }
    };
}

pub fn main() u8 {
    const Buffer4k = Buffer(0x1000);
    var buf = Buffer4k.initStack();
    warn("buf.buffer[254]={}\n", buf.buffer[254]);

    var direct_allocator = std.heap.DirectAllocator.init();
    defer direct_allocator.deinit();
    var allocator = &direct_allocator.allocator;

    var bufAlloced = allocator.alloc(Buffer4k, 1) catch { std.debug.warn("OOM\n"); return 0xFF; };
    bufAlloced[0].initHeap();
    var r1 = bufAlloced[0].buffer[254];
    warn("bufAlloced[0].buffer[254]={}\n", r1);

    return buf.buffer[254];
}

$ zig build-exe main.y.zig
| "initStack typeOf(Self): ", type
| "initStack typeOf(self): ", Buffer(4096)
| "initStack typeof(self.buffer): ", [4096]u8
| "initHeap typeof(self): ", *Buffer(4096)
| "fill typeof(self): ", *Buffer(4096)
| "fill typeof(ptr):", *u8
| "fill typeof(ptr.*):", u8