incorrect "error: dependency loop detected"

[buzmeg]

Zig Version

0.11.0-dev.3952+82a9d5d78

Steps to Reproduce and Observed Behavior

The following code refuses to compile on 0.11.0-dev.3952+82a9d5d78 but compiles just fine on Godbolt on 0.10.0. So, the dependency loop error if presumably false.

src/main.zig:16:1: error: dependency loop detected
const ContinuationStackType = std.BoundedArray(SmolkContinuationNative, MAX_CONTINUATION_STACK_SIZE);

const std = @import("std");


const KO_Ref = u16;
const KO_State = u16;

const KOErr = error {
    GENERIC,
};


const MAX_CONTINUATION_STACK_SIZE = 8;



const ContinuationStackType = std.BoundedArray(SmolkContinuationNative, MAX_CONTINUATION_STACK_SIZE);
var kont_continuation_stack: ContinuationStackType = .{};

const SmolkPointerContinuationFunction = *const fn (pkos: *KO_State, kont_stack: *ContinuationStackType, args: SmolkContinuationNative) KOErr!SmolkContinuationNative;

const SMOLK_CONTINUATION_INITIAL_CALL_STATE = 1;

const SmolkContinuationNative = struct {
    pcfn: SmolkPointerContinuationFunction,
    kor_result: KO_Ref,
};


pub fn kont_fail(pkos: *KO_State, kont_stack: *ContinuationStackType, args: SmolkContinuationNative) KOErr!SmolkContinuationNative
{
    _ = pkos;
    _ = kont_stack;
    _ = args;

    std.debug.print("FAIL!\n", .{});

    return KOErr.GENERIC;
}

pub fn main() !void {
    try kont_continuation_stack.append(.{
        .pcfn = kont_fail,
        .kor_result = 0,
    });
    std.debug.print("Stack: {any}\n", .{kont_continuation_stack});
}

Expected Behavior

Expected to compile.

[jsign]

Looks like the same report as done in https://github.com/ziglang/zig/issues/14353.

In your case, SmolkContinuationNative depends on SmolkPointerContinouationFunction, a function pointer with SmolkContinuationNative in its args.

Yesterday, I had the same dependency loop compilation problem for some C-imported header file which was doing a similar thing from a translated .h file.

[pwbh]

Same happens for libuv, dependency loop detected for *c.uv_stream_t

const ConnectionCb = *const fn (server: *c.uv_stream_t, status: i32) void;

pub fn init(loop: Loop) Tcp {
    var handle: c.uv_tcp_t = undefined;
    c.uv_tcp_init(loop.loop, &handle);
    return .{ .handle = handle, .addr = .{} };
}

pub fn listen(self: Tcp, addr: []const u8, port: i32, backlog: usize, cb: ConnectionCb) !void {
    c.uv_ip4_addr(addr, port, &self.addr);
    c.uv_tcp_bind(&self.handle, @bitCast(addr), 0);
    const result = c.uv_listen(@alignCast(self.handle), backlog, cb);
    try errors.translate(result);
}

[mlugg]

This instance is, I think, working correctly, and was simply a design flaw in BoundedArray where it used @alignOf on the child type, rather than doing what ArrayList does and having a specific representation for "default alignment". Additionally, BoundedArray has now been removed from the standard library, so this no longer reproduces.