diff --git a/src/AccessorNames.ts b/src/AccessorNames.ts
index b6edd645..b56b2a3b 100644
--- a/src/AccessorNames.ts
+++ b/src/AccessorNames.ts
@@ -73,6 +73,7 @@ export function getAccessorName(
 
 export const unionIdentifierTypeAttributeKind = new TypeAttributeKind<Set<number>>(
     "unionIdentifier",
+    true,
     (a, b) => a.union(b),
     _ => undefined,
     undefined
@@ -88,6 +89,7 @@ export function makeUnionIdentifierAttribute(): TypeAttributes {
 
 export const unionMemberNamesTypeAttributeKind = new TypeAttributeKind<Map<number, AccessorEntry>>(
     "unionMemberNames",
+    true,
     (a, b) => a.merge(b),
     _ => undefined,
     undefined
diff --git a/src/ConvenienceRenderer.ts b/src/ConvenienceRenderer.ts
index aef159e5..86cbc079 100644
--- a/src/ConvenienceRenderer.ts
+++ b/src/ConvenienceRenderer.ts
@@ -46,21 +46,24 @@ function splitDescription(descriptions: OrderedSet<string> | undefined): string[
 
 export type ForbiddenWordsInfo = { names: (Name | string)[]; includeGlobalForbidden: boolean };
 
-const assignedNameAttributeKind = new TypeAttributeKind<Name>("assignedName", undefined, undefined, undefined);
+const assignedNameAttributeKind = new TypeAttributeKind<Name>("assignedName", false, undefined, undefined, undefined);
 const assignedPropertyNamesAttributeKind = new TypeAttributeKind<Map<string, Name>>(
     "assignedPropertyNames",
+    false,
     undefined,
     undefined,
     undefined
 );
 const assignedMemberNamesAttributeKind = new TypeAttributeKind<Map<Type, Name>>(
     "assignedMemberNames",
+    false,
     undefined,
     undefined,
     undefined
 );
 const assignedCaseNamesAttributeKind = new TypeAttributeKind<Map<string, Name>>(
     "assignedCaseNames",
+    false,
     undefined,
     undefined,
     undefined
diff --git a/src/TypeAttributes.ts b/src/TypeAttributes.ts
index f31aaf0a..8210d36d 100644
--- a/src/TypeAttributes.ts
+++ b/src/TypeAttributes.ts
@@ -10,6 +10,7 @@ export class TypeAttributeKind<T> {
 
     constructor(
         readonly name: string,
+        readonly inIdentity: boolean,
         combine: ((a: T, b: T) => T) | undefined,
         makeInferred: ((a: T) => T | undefined) | undefined,
         stringify: ((a: T) => string | undefined) | undefined
@@ -106,6 +107,7 @@ export function makeTypeAttributesInferred(attr: TypeAttributes): TypeAttributes
 
 export const descriptionTypeAttributeKind = new TypeAttributeKind<OrderedSet<string>>(
     "description",
+    false,
     setUnion,
     _ => OrderedSet(),
     descriptions => {
@@ -122,6 +124,7 @@ export const descriptionTypeAttributeKind = new TypeAttributeKind<OrderedSet<str
 );
 export const propertyDescriptionsTypeAttributeKind = new TypeAttributeKind<Map<string, OrderedSet<string>>>(
     "propertyDescriptions",
+    false,
     (a, b) => a.mergeWith(setUnion, b),
     _ => Map(),
     undefined
diff --git a/src/TypeBuilder.ts b/src/TypeBuilder.ts
index 7fa87c47..7dcd6dbe 100644
--- a/src/TypeBuilder.ts
+++ b/src/TypeBuilder.ts
@@ -66,6 +66,7 @@ function provenanceToString(p: Set<TypeRef>): string {
 // non-inferred form in the final graph.
 export const provenanceTypeAttributeKind = new TypeAttributeKind<Set<TypeRef>>(
     "provenance",
+    false,
     setUnion,
     a => a,
     provenanceToString
diff --git a/src/TypeNames.ts b/src/TypeNames.ts
index 7c26027b..b77fdac1 100644
--- a/src/TypeNames.ts
+++ b/src/TypeNames.ts
@@ -237,6 +237,7 @@ export function typeNamesUnion(c: Collection<any, TypeNames>): TypeNames {
 
 export const namesTypeAttributeKind = new TypeAttributeKind<TypeNames>(
     "names",
+    false,
     (a, b) => a.add(b),
     a => a.makeInferred(),
     a => a.toString()