nested packed structs cause an infinite loop during semantic analysis

[jcollie]

Zig Version

0.15.1, 0.14.1, 0.13.0

Steps to Reproduce and Observed Behavior

Given test.zig:

const S = packed struct(u32) {
    b: packed struct(u8) {
        b1: u1 = 0,
        b2: u7 = 0,
    },
    a: u24 = 0,
};

test "packed struct" {
    const x: S = .{ .b = .{ .b1 = 1 } };
    _ = x;
}

zig test test.zig appears to get stuck in an infinite loop during semantic analysis. This happens on 0.15.1, 0.14.1 and 0.13.0.

Expected Behavior

Code should compile or cause an error in a finite amount of time.

Thanks to chocapix on Discord for help minimizing the reproduction.

[Vexu]

Duplicate of #19730