zig/test/behavior/bugs/656.zig

const expect = @import("std").testing.expect;
const builtin = @import("builtin");

const PrefixOp = union(enum) {
    Return,
    AddrOf: Value,
};

const Value = struct {
    align_expr: ?u32,
};

test "optional if after an if in a switch prong of a switch with 2 prongs in an else" {
    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
    if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
    try foo(false, true);
}

fn foo(a: bool, b: bool) !void {
    var prefix_op = PrefixOp{
        .AddrOf = Value{ .align_expr = 1234 },
    };
    if (a) {} else {
        switch (prefix_op) {
            PrefixOp.AddrOf => |addr_of_info| {
                if (b) {}
                if (addr_of_info.align_expr) |align_expr| {
                    try expect(align_expr == 1234);
                }
            },
            PrefixOp.Return => {},
        }
    }
}