diff --git a/tools/gulp/tasks/release.ts b/tools/gulp/tasks/release.ts
index 3e089c45770..5e982c0ac6f 100644
--- a/tools/gulp/tasks/release.ts
+++ b/tools/gulp/tasks/release.ts
@@ -12,7 +12,7 @@ const argv = minimist(process.argv.slice(3));
 
 /** Removes redundant spec files from the release. TypeScript creates definition files for specs. */
 // TODO(devversion): tsconfig files should share code and don't generate spec files for releases.
-task(':build:release:clean-spec', cleanTask('dist/**/*(-|.)spec.*'));
+task(':build:release:clean-spec', cleanTask('dist/**/*+(-|.)spec.*'));
 
 
 task('build:release', function(done: () => void) {