diff --git a/packages/@ngtools/webpack/src/loader.spec.ts b/packages/@ngtools/webpack/src/loader.spec.ts
index dbd7b731e2df..c9b5338d3348 100644
--- a/packages/@ngtools/webpack/src/loader.spec.ts
+++ b/packages/@ngtools/webpack/src/loader.spec.ts
@@ -34,6 +34,27 @@ describe('@ngtools/webpack', () => {
         expect(refactor2.sourceText).toMatch(/\(\{\s*otherValue2: 2\s*,\s*otherValue3: 3\s*}\)/);
         expect(refactor2.sourceText).toMatch(/\(\{\s*otherValue4: 4\s*}\)/);
       });
+
+      it('should work without a root name', () => {
+        const host = new WebpackCompilerHost({}, '');
+        host.writeFile('/file.ts', `
+          import './file2.ts';
+        `, false);
+        host.writeFile('/file2.ts', `
+          @SomeDecorator({ moduleId: 123 }) class CLS {}
+          @SomeDecorator({ moduleId: 123, otherValue1: 1 }) class CLS2 {}
+          @SomeDecorator({ otherValue2: 2, moduleId: 123, otherValue3: 3 }) class CLS3 {}
+          @SomeDecorator({ otherValue4: 4, moduleId: 123 }) class CLS4 {}
+        `, false);
+
+        const program = ts.createProgram(['/file.ts'], {}, host);
+        const refactor = new TypeScriptFileRefactor('/file2.ts', host, program);
+        removeModuleIdOnlyForTesting(refactor);
+        expect(refactor.sourceText).toMatch(/\(\{\s+}\)/);
+        expect(refactor.sourceText).toMatch(/\(\{\s*otherValue1: 1\s*}\)/);
+        expect(refactor.sourceText).toMatch(/\(\{\s*otherValue2: 2\s*,\s*otherValue3: 3\s*}\)/);
+        expect(refactor.sourceText).toMatch(/\(\{\s*otherValue4: 4\s*}\)/);
+      });
     });
   });
 });
diff --git a/packages/@ngtools/webpack/src/refactor.ts b/packages/@ngtools/webpack/src/refactor.ts
index 7b11da71d3a1..2f5c02a2db63 100644
--- a/packages/@ngtools/webpack/src/refactor.ts
+++ b/packages/@ngtools/webpack/src/refactor.ts
@@ -45,9 +45,9 @@ export class TypeScriptFileRefactor {
       this._sourceFile = _program.getSourceFile(fileName);
     }
     if (!this._sourceFile) {
-      this._program = null;
+      // this._program = null;
       this._sourceFile = ts.createSourceFile(fileName, _host.readFile(fileName),
-        ts.ScriptTarget.Latest);
+        ts.ScriptTarget.Latest, true);
     }
     this._sourceText = this._sourceFile.getFullText(this._sourceFile);
     this._sourceString = new MagicString(this._sourceText);