Add explicit CRDT edit contracts and structured query values

src/capability-model/generics.ts

@@ -16,7 +16,7 @@ export type ValueTypeExpression =
   | Extract<ValueType, { kind: "builtin" | "scalar" | "message" }>
   | { kind: "parameter"; parameterId: string }
   | { kind: "record"; fields: Record<string, ValueTypeExpression> }
-  | { kind: "list" | "optional"; value: ValueTypeExpression }
+  | { kind: "list" | "optional" | "change"; value: ValueTypeExpression }
   | { kind: "object-ref"; expectation: ObjectTypeExpression }
   | { kind: "alias"; definitionId: string; arguments: TypeArgumentExpression[] };
 
@@ -184,10 +184,10 @@ export const isStorableType = (
       case "list":
       case "optional":
         return visit(value.value, depth + 1);
-      // Records currently have RPC codecs, not ordinary-state persistence codecs.
-      // A generic bound must not promise storage that the installed model rejects.
-      case "record":
+      case "change":
         return false;
+      case "record":
+        return Object.values(value.fields).every((field) => visit(field, depth + 1));
     }
   };
   return visit(type, 0);
@@ -216,6 +216,7 @@ export const canonicalTypeArgument = (argument: ClosedTypeArgument): string => {
         return ["message", value.descriptorId];
       case "object-ref":
         return ["object-ref", target(value.expectation)];
+      case "change":
       case "list":
       case "optional":
         return [value.kind, type(value.value, depth + 1)];
@@ -323,6 +324,7 @@ export class TypeSubstitution {
         return { kind: "scalar", name: expression.name };
       case "message":
         return { kind: "message", descriptorId: expression.descriptorId };
+      case "change":
       case "list":
       case "optional":
         return { kind: expression.kind, value: this.value(expression.value, `${path}.${expression.kind}`, depth + 1) };