iter 22-tidy.6.1: write_class_def + write_instance_def — full Form-B projection

examples/test_22b3_default_e2e.prose.txt

@@ -0,0 +1,16 @@
+// module test_22b3_default_e2e
+
+class D a {
+  fn dval(x: a) -> Int default {
+    |x: a| -> Int {
+      99
+    }
+  }
+}
+
+instance D Int {
+}
+
+fn main() -> Unit with IO {
+  do io/print_int(dval(0))
+}