diff --git a/packages/angular_devkit/build_angular/src/builders/dev-server/webpack-server.ts b/packages/angular_devkit/build_angular/src/builders/dev-server/webpack-server.ts
index ee4b369a89cb..0f1b51b59d80 100644
--- a/packages/angular_devkit/build_angular/src/builders/dev-server/webpack-server.ts
+++ b/packages/angular_devkit/build_angular/src/builders/dev-server/webpack-server.ts
@@ -263,7 +263,7 @@ export function serveWebpackBrowser(
             ...buildEvent,
             baseUrl: serverAddress,
             stats: generateBuildEventStats(webpackRawStats, browserOptions),
-          };
+          } as DevServerBuilderOutput;
         }),
       );
     }),
diff --git a/tsconfig.json b/tsconfig.json
index f8cce3dbe85c..73c91f774209 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -25,6 +25,7 @@
       "@angular-devkit/schematics/tools": ["./packages/angular_devkit/schematics/tools/index"],
       "@angular-devkit/schematics/testing": ["./packages/angular_devkit/schematics/testing/index"],
       "@angular-devkit/architect/testing": ["./packages/angular_devkit/architect/testing/index"],
+      "@angular-devkit/build-webpack": ["./packages/angular_devkit/build_webpack"],
       "@angular-devkit/*": ["./packages/angular_devkit/*/src"],
       "@angular/*": ["./packages/angular/*/src"],
       "@angular/build/private": ["./packages/angular/build/src/private"],