1fn b() !u32 {
 2    return 2;
 3}
 4
 5export fn a() void {
 6    for (b()) |_| {}
 7}
 8
 9// error
10//
11// :6:11: error: type '@typeInfo(@typeInfo(@TypeOf(tmp.b)).@"fn".return_type.?).error_union.error_set!u32' is not indexable and not a range
12// :6:11: note: for loop operand must be a range, array, slice, tuple, or vector
13// :6:11: note: consider using 'try', 'catch', or 'if'