Index: lib/runtime/dart/async.js |
diff --git a/lib/runtime/dart/async.js b/lib/runtime/dart/async.js |
index 550d0819998669110f45588c6488357f116dcf9b..fe1810d1928d0ed6448ec71c5ec05bc06fbdc704 100644 |
--- a/lib/runtime/dart/async.js |
+++ b/lib/runtime/dart/async.js |
@@ -43,7 +43,7 @@ var async; |
toString() { |
let result = `Uncaught Error: ${this.error}`; |
if (this.stackTrace != null) { |
- result = core.String['+'](result, `\nStack Trace:\n${this.stackTrace}`); |
+ result = dart.notNull(result) + `\nStack Trace:\n${this.stackTrace}`; |
} |
return result; |
} |