diff --git a/modules/@angular/compiler-cli/src/path_mapped_reflector_host.ts b/modules/@angular/compiler-cli/src/path_mapped_reflector_host.ts
index d72eb5bf58..13423ef142 100644
--- a/modules/@angular/compiler-cli/src/path_mapped_reflector_host.ts
+++ b/modules/@angular/compiler-cli/src/path_mapped_reflector_host.ts
@@ -74,7 +74,11 @@ export class PathMappedReflectorHost extends ReflectorHost {
     // If a file does not yet exist (because we compile it later), we still need to
     // assume it exists so that the `resolve` method works!
     if (!this.context.fileExists(importedFile)) {
-      this.context.assumeFileExists(importedFile);
+      if (this.options.rootDirs && this.options.rootDirs.length > 0) {
+        this.context.assumeFileExists(path.join(this.options.rootDirs[0], importedFile));
+      } else {
+        this.context.assumeFileExists(importedFile);
+      }
     }
 
     const resolvable = (candidate: string) => {