diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index a9fe9a32556..f5e20f96480 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -2407,6 +2407,14 @@ declare namespace ts {
         fileExists(path: string): boolean;
         readFile(path: string): string | undefined;
     }
+    /**
+     * Branded string for keeping track of when we've turned an ambiguous path
+     * specified like "./blah" to an absolute path to an actual
+     * tsconfig file, e.g. "/root/blah/tsconfig.json"
+     */
+    type ResolvedConfigFileName = string & {
+        _isResolvedConfigFileName: never;
+    };
     type WriteFileCallback = (fileName: string, data: string, writeByteOrderMark: boolean, onError: ((message: string) => void) | undefined, sourceFiles?: ReadonlyArray<SourceFile>) => void;
     class OperationCanceledException {
     }
@@ -3965,6 +3973,14 @@ declare namespace ts {
         tab = 9,
         verticalTab = 11
     }
+    interface UpToDateHost {
+        fileExists(fileName: string): boolean;
+        getModifiedTime(fileName: string): Date;
+        getUnchangedTime?(fileName: string): Date | undefined;
+        getLastStatus?(fileName: string): UpToDateStatus | undefined;
+        setLastStatus?(fileName: string, status: UpToDateStatus): void;
+        parseConfigFile?(configFilePath: ResolvedConfigFileName): ParsedCommandLine | undefined;
+    }
     interface ModuleResolutionHost {
         fileExists(fileName: string): boolean;
         readFile(fileName: string): string | undefined;
@@ -8923,7 +8939,7 @@ declare namespace ts {
     /**
      * Returns the target config filename of a project reference
      */
-    function resolveProjectReferencePath(host: CompilerHost, ref: ProjectReference): string | undefined;
+    function resolveProjectReferencePath(host: CompilerHost | UpToDateHost, ref: ProjectReference): ResolvedConfigFileName;
     /**
      * Returns a DiagnosticMessage if we won't include a resolved module due to its extension.
      * The DiagnosticMessage's parameters are the imported module name, and the filename it resolved to.
@@ -9405,14 +9421,6 @@ declare namespace ts {
     function createWatchProgram<T extends BuilderProgram>(host: WatchCompilerHostOfConfigFile<T>): WatchOfConfigFile<T>;
 }
 declare namespace ts {
-    /**
-     * Branded string for keeping track of when we've turned an ambiguous path
-     * specified like "./blah" to an absolute path to an actual
-     * tsconfig file, e.g. "/root/blah/tsconfig.json"
-     */
-    type ResolvedConfigFileName = string & {
-        _isResolvedConfigFileName: never;
-    };
     interface BuildHost {
         verbose(diag: DiagnosticMessage, ...args: string[]): void;
         error(diag: DiagnosticMessage, ...args: string[]): void;
@@ -9579,6 +9587,12 @@ declare namespace ts {
         resolveProjectName: (name: string) => ResolvedConfigFileName | undefined;
         startWatching: () => void;
     };
+    /**
+     * Gets the UpToDateStatus for a project
+     */
+    function getUpToDateStatus(host: UpToDateHost, project: ParsedCommandLine | undefined): UpToDateStatus;
+    function getAllProjectOutputs(project: ParsedCommandLine): ReadonlyArray<string>;
+    function formatUpToDateStatus<T>(configFileName: string, status: UpToDateStatus, relName: (fileName: string) => string, formatMessage: (message: DiagnosticMessage, ...args: string[]) => T): T | undefined;
 }
 //# sourceMappingURL=compiler.d.ts.map
 declare namespace ts.server {
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
index 8bb1efe058b..62413b0753b 100644
--- a/tests/baselines/reference/api/typescript.d.ts
+++ b/tests/baselines/reference/api/typescript.d.ts
@@ -1716,6 +1716,14 @@ declare namespace ts {
         fileExists(path: string): boolean;
         readFile(path: string): string | undefined;
     }
+    /**
+     * Branded string for keeping track of when we've turned an ambiguous path
+     * specified like "./blah" to an absolute path to an actual
+     * tsconfig file, e.g. "/root/blah/tsconfig.json"
+     */
+    type ResolvedConfigFileName = string & {
+        _isResolvedConfigFileName: never;
+    };
     type WriteFileCallback = (fileName: string, data: string, writeByteOrderMark: boolean, onError: ((message: string) => void) | undefined, sourceFiles?: ReadonlyArray<SourceFile>) => void;
     class OperationCanceledException {
     }
@@ -2572,6 +2580,14 @@ declare namespace ts {
         oldProgram?: Program;
         configFileParsingDiagnostics?: ReadonlyArray<Diagnostic>;
     }
+    interface UpToDateHost {
+        fileExists(fileName: string): boolean;
+        getModifiedTime(fileName: string): Date;
+        getUnchangedTime?(fileName: string): Date | undefined;
+        getLastStatus?(fileName: string): UpToDateStatus | undefined;
+        setLastStatus?(fileName: string, status: UpToDateStatus): void;
+        parseConfigFile?(configFilePath: ResolvedConfigFileName): ParsedCommandLine | undefined;
+    }
     interface ModuleResolutionHost {
         fileExists(fileName: string): boolean;
         readFile(fileName: string): string | undefined;
@@ -4142,7 +4158,7 @@ declare namespace ts {
     /**
      * Returns the target config filename of a project reference
      */
-    function resolveProjectReferencePath(host: CompilerHost, ref: ProjectReference): string | undefined;
+    function resolveProjectReferencePath(host: CompilerHost | UpToDateHost, ref: ProjectReference): ResolvedConfigFileName;
 }
 declare namespace ts {
     interface EmitOutput {
@@ -4388,14 +4404,6 @@ declare namespace ts {
     function createWatchProgram<T extends BuilderProgram>(host: WatchCompilerHostOfConfigFile<T>): WatchOfConfigFile<T>;
 }
 declare namespace ts {
-    /**
-     * Branded string for keeping track of when we've turned an ambiguous path
-     * specified like "./blah" to an absolute path to an actual
-     * tsconfig file, e.g. "/root/blah/tsconfig.json"
-     */
-    type ResolvedConfigFileName = string & {
-        _isResolvedConfigFileName: never;
-    };
     interface BuildHost {
         verbose(diag: DiagnosticMessage, ...args: string[]): void;
         error(diag: DiagnosticMessage, ...args: string[]): void;
@@ -4562,6 +4570,12 @@ declare namespace ts {
         resolveProjectName: (name: string) => ResolvedConfigFileName | undefined;
         startWatching: () => void;
     };
+    /**
+     * Gets the UpToDateStatus for a project
+     */
+    function getUpToDateStatus(host: UpToDateHost, project: ParsedCommandLine | undefined): UpToDateStatus;
+    function getAllProjectOutputs(project: ParsedCommandLine): ReadonlyArray<string>;
+    function formatUpToDateStatus<T>(configFileName: string, status: UpToDateStatus, relName: (fileName: string) => string, formatMessage: (message: DiagnosticMessage, ...args: string[]) => T): T | undefined;
 }
 declare namespace ts {
     interface Node {