diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index ae1e7c16d00..f263c53a649 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -5616,8 +5616,8 @@ namespace ts {
         root: ConditionalRoot;
         checkType: Type;
         extendsType: Type;
-        resolvedTrueType: Type;
-        resolvedFalseType: Type;
+        resolvedTrueType?: Type;
+        resolvedFalseType?: Type;
         /* @internal */
         resolvedInferredTrueType?: Type; // The `trueType` instantiated with the `combinedMapper`, if present
         /* @internal */
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index f23a441f98c..345ee175a1f 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -2722,8 +2722,8 @@ declare namespace ts {
         root: ConditionalRoot;
         checkType: Type;
         extendsType: Type;
-        resolvedTrueType: Type;
-        resolvedFalseType: Type;
+        resolvedTrueType?: Type;
+        resolvedFalseType?: Type;
     }
     export interface TemplateLiteralType extends InstantiableType {
         texts: readonly string[];
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
index 8a9603b7b7c..dc6b0f2787f 100644
--- a/tests/baselines/reference/api/typescript.d.ts
+++ b/tests/baselines/reference/api/typescript.d.ts
@@ -2722,8 +2722,8 @@ declare namespace ts {
         root: ConditionalRoot;
         checkType: Type;
         extendsType: Type;
-        resolvedTrueType: Type;
-        resolvedFalseType: Type;
+        resolvedTrueType?: Type;
+        resolvedFalseType?: Type;
     }
     export interface TemplateLiteralType extends InstantiableType {
         texts: readonly string[];