zig/test/cases/switch_prong_err_enum.zig
Andrew Kelley 0ad1239522 rework enums and unions and their relationship to each other
* @enumTagName renamed to @tagName and it works on enums and
   union-enums
 * Remove the EnumTag type. Now there is only enum and union,
   and the tag type of a union is always an enum.
 * unions support specifying the tag enum type, and they support
   inferring an enum tag type.
 * Enums no longer support field types but they do support
   setting the tag values. Likewise union-enums when inferring
   an enum tag type support setting the tag values.
 * It is now an error for enums and unions to have 0 fields.
 * switch statements support union-enums

closes #618
2017-12-03 20:43:56 -05:00

31 lines
619 B
Zig

const assert = @import("std").debug.assert;
var read_count: u64 = 0;
fn readOnce() -> %u64 {
read_count += 1;
return read_count;
}
error InvalidDebugInfo;
const FormValue = union(enum) {
Address: u64,
Other: bool,
};
fn doThing(form_id: u64) -> %FormValue {
return switch (form_id) {
17 => FormValue { .Address = %return readOnce() },
else => error.InvalidDebugInfo,
}
}
test "switch prong returns error enum" {
switch (%%doThing(17)) {
FormValue.Address => |payload| { assert(payload == 1); },
else => unreachable,
}
assert(read_count == 1);
}