diff --git a/src/checker/runtime.ts b/src/checker/runtime.ts
index de2694b..403b295 100644
--- a/src/checker/runtime.ts
+++ b/src/checker/runtime.ts
@@ -19,7 +19,7 @@ import {
 
 import { CaseInsensitiveMap } from './fs';
 import { isCaseInsensitive } from '../helpers';
-
+
 const caseInsensitive = isCaseInsensitive();
 
 if (!module.parent) {
@@ -95,10 +95,10 @@ function createChecker(receive: (cb: (msg: Req) => void) => void, send: (msg: Re
         fileName => fileName.toLowerCase() :
         (fileName => fileName);
 
-    let watchHost: ts.WatchCompilerHostOfFilesAndCompilerOptions;
+    let watchHost: ts.WatchCompilerHostOfFilesAndCompilerOptions<ts.SemanticDiagnosticsBuilderProgram>;
     let watch: ts.WatchOfFilesAndCompilerOptions<ts.SemanticDiagnosticsBuilderProgram>;
-
-    function createWatchHost(): ts.WatchCompilerHostOfFilesAndCompilerOptions & ts.BuilderProgramHost {
+
+    function createWatchHost(): ts.WatchCompilerHostOfFilesAndCompilerOptions<ts.SemanticDiagnosticsBuilderProgram> & ts.BuilderProgramHost {
         return {
             rootFiles: getRootFiles(),
             options: compilerOptions,
@@ -117,7 +117,9 @@ function createChecker(receive: (cb: (msg: Req) => void) => void, send: (msg: Re
             watchFile,
             watchDirectory,
 
-            createHash: (...args) => compiler.sys.createHash.apply(compiler.sys, args)
+            createProgram: compiler.createSemanticDiagnosticsBuilderProgram,
+
+            createHash: (...args) => compiler.sys.createHash.apply(compiler.sys, args)
         };
 
         function readFile(fileName: string) {
@@ -131,7 +133,7 @@ function createChecker(receive: (cb: (msg: Req) => void) => void, send: (msg: Re
 
     function createWatch(): ts.WatchOfFilesAndCompilerOptions<ts.SemanticDiagnosticsBuilderProgram> {
         watchHost = createWatchHost();
-        return compiler.createWatchBuilderProgram(watchHost, compiler.createSemanticDiagnosticsBuilderProgram);
+        return compiler.createWatchProgram(watchHost);
     }
 
     function getProgram(): ts.SemanticDiagnosticsBuilderProgram {
@@ -385,10 +387,10 @@ function createChecker(receive: (cb: (msg: Req) => void) => void, send: (msg: Re
         replyOk(seq, {
             files: getProgram().getSourceFiles().map(f => f.fileName)
         });
-    }
-
-    function isAffectedSourceFile(affected: ts.SourceFile | ts.Program): affected is ts.SourceFile {
-        return (affected as ts.SourceFile).kind === compiler.SyntaxKind.SourceFile;
+    }
+
+    function isAffectedSourceFile(affected: ts.SourceFile | ts.Program): affected is ts.SourceFile {
+        return (affected as ts.SourceFile).kind === compiler.SyntaxKind.SourceFile;
     }
 
     function processDiagnostics({ seq }: Diagnostics.Request) {