cgen: fix type_default for option type when the default expr is none
#711
| Job | Run time |
|---|---|
| 6m 11s | |
| 2m 34s | |
| 4m 35s | |
| 2m 18s | |
| 15m 38s |
none
#711
| Job | Run time |
|---|---|
| 6m 11s | |
| 2m 34s | |
| 4m 35s | |
| 2m 18s | |
| 15m 38s |