| 204 | | The return kind of abstract class constraints must be {{{+}}}. We don't yet support default instances in type class declarations #90. |
| | 204 | Region, effect and closure classes are abstract, as we do not define instance functions for them. Classes such as {{{Mutable}}} and {{{Pure}}} are defined as abstract classes in the the base libraries. For example: |
| | 205 | |
| | 206 | {{{ |
| | 207 | class Mutable :: % -> + |
| | 208 | class Pure :: ! -> + |
| | 209 | }}} |
| | 210 | |
| | 211 | The return kind of abstract class constraints must be {{{+}}} (witnesses). |
| | 212 | |
| | 213 | Value type classes are as per Haskell, though we don't yet support default instances #90. |
