@@ -486,8 +486,7 @@ export class NgCompiler {
     // Execute the typeCheck phase of each decorator in the program.
     const prepSpan = this.perfRecorder.start('typeCheckPrep');
     const ctx = new TypeCheckContext(
-        typeCheckingConfig, host, compilation.refEmitter!, compilation.reflector,
-        host.typeCheckFile);
+        typeCheckingConfig, compilation.refEmitter!, compilation.reflector, host.typeCheckFile);
     compilation.traitCompiler.typeCheck(ctx);
     this.perfRecorder.stop(prepSpan);
 
 
@@ -38,11 +38,9 @@ export class TypeCheckContext {
   private typeCheckFile: TypeCheckFile;
 
   constructor(
-      private config: TypeCheckingConfig, compilerHost: ts.CompilerHost,
-      private refEmitter: ReferenceEmitter, private reflector: ReflectionHost,
-      typeCheckFilePath: AbsoluteFsPath) {
-    this.typeCheckFile =
-        new TypeCheckFile(typeCheckFilePath, config, refEmitter, reflector, compilerHost);
+      private config: TypeCheckingConfig, private refEmitter: ReferenceEmitter,
+      private reflector: ReflectionHost, typeCheckFilePath: AbsoluteFsPath) {
+    this.typeCheckFile = new TypeCheckFile(typeCheckFilePath, config, refEmitter, reflector);
   }
 
   /**
 
@@ -33,12 +33,11 @@ export class TypeCheckFile extends Environment {
   private tcbStatements: ts.Statement[] = [];
 
   constructor(
-      readonly fileName: AbsoluteFsPath, config: TypeCheckingConfig, refEmitter: ReferenceEmitter,
-      reflector: ReflectionHost, compilerHost: ts.CompilerHost) {
+      private fileName: string, config: TypeCheckingConfig, refEmitter: ReferenceEmitter,
+      reflector: ReflectionHost) {
     super(
         config, new ImportManager(new NoopImportRewriter(), 'i'), refEmitter, reflector,
-        ts.createSourceFile(
-            compilerHost.getCanonicalFileName(fileName), '', ts.ScriptTarget.Latest, true));
+        ts.createSourceFile(fileName, '', ts.ScriptTarget.Latest, true));
   }
 
   addTypeCheckBlock(
@@ -50,7 +49,7 @@ export class TypeCheckFile extends Environment {
   }
 
   render(): ts.SourceFile {
-    let source: string = this.importManager.getAllImports(this.contextFile.fileName)
+    let source: string = this.importManager.getAllImports(this.fileName)
                              .map(i => `import * as ${i.qualifier} from '${i.specifier}';`)
                              .join('\n') +
         '\n\n';
@@ -76,7 +75,7 @@ export class TypeCheckFile extends Environment {
     source += '\nexport const IS_A_MODULE = true;\n';
 
     return ts.createSourceFile(
-        this.contextFile.fileName, source, ts.ScriptTarget.Latest, true, ts.ScriptKind.TS);
+        this.fileName, source, ts.ScriptTarget.Latest, true, ts.ScriptKind.TS);
   }
 
   getPreludeStatements(): ts.Statement[] {
 
@@ -262,7 +262,7 @@ export function typecheck(
     new LogicalProjectStrategy(reflectionHost, logicalFs),
   ]);
   const ctx = new TypeCheckContext(
-      {...ALL_ENABLED_CONFIG, ...config}, host, emitter, reflectionHost, typeCheckFilePath);
+      {...ALL_ENABLED_CONFIG, ...config}, emitter, reflectionHost, typeCheckFilePath);
 
   const templateUrl = 'synthetic.html';
   const templateFile = new ParseSourceFile(template, templateUrl);
 
@@ -45,7 +45,7 @@ runInEachFileSystem(() => {
       const host = new NgtscCompilerHost(getFileSystem());
       const file = new TypeCheckFile(
           _('/_typecheck_.ts'), ALL_ENABLED_CONFIG, new ReferenceEmitter([]),
-          /* reflector */ null!, host);
+          /* reflector */ null!);
       const sf = file.render();
       expect(sf.statements.length).toBe(1);
     });
@@ -75,8 +75,8 @@ TestClass.ngTypeCtor({value: 'test'});
           new AbsoluteModuleStrategy(program, checker, moduleResolver, reflectionHost),
           new LogicalProjectStrategy(reflectionHost, logicalFs),
         ]);
-        const ctx = new TypeCheckContext(
-            ALL_ENABLED_CONFIG, host, emitter, reflectionHost, _('/_typecheck_.ts'));
+        const ctx =
+            new TypeCheckContext(ALL_ENABLED_CONFIG, emitter, reflectionHost, _('/_typecheck_.ts'));
         const TestClass =
             getDeclaration(program, _('/main.ts'), 'TestClass', isNamedClassDeclaration);
         ctx.addInlineTypeCtor(
@@ -111,8 +111,8 @@ TestClass.ngTypeCtor({value: 'test'});
           new AbsoluteModuleStrategy(program, checker, moduleResolver, reflectionHost),
           new LogicalProjectStrategy(reflectionHost, logicalFs),
         ]);
-        const ctx = new TypeCheckContext(
-            ALL_ENABLED_CONFIG, host, emitter, reflectionHost, _('/_typecheck_.ts'));
+        const ctx =
+            new TypeCheckContext(ALL_ENABLED_CONFIG, emitter, reflectionHost, _('/_typecheck_.ts'));
         const TestClass =
             getDeclaration(program, _('/main.ts'), 'TestClass', isNamedClassDeclaration);
         ctx.addInlineTypeCtor(
@@ -153,8 +153,8 @@ TestClass.ngTypeCtor({value: 'test'});
           new AbsoluteModuleStrategy(program, checker, moduleResolver, reflectionHost),
           new LogicalProjectStrategy(reflectionHost, logicalFs),
         ]);
-        const ctx = new TypeCheckContext(
-            ALL_ENABLED_CONFIG, host, emitter, reflectionHost, _('/_typecheck_.ts'));
+        const ctx =
+            new TypeCheckContext(ALL_ENABLED_CONFIG, emitter, reflectionHost, _('/_typecheck_.ts'));
         const TestClass =
             getDeclaration(program, _('/main.ts'), 'TestClass', isNamedClassDeclaration);
         ctx.addInlineTypeCtor(