diff --git a/dwds/lib/src/services/expression_compiler_service.dart b/dwds/lib/src/services/expression_compiler_service.dart
index e0c40348e..2edcacca2 100644
--- a/dwds/lib/src/services/expression_compiler_service.dart
+++ b/dwds/lib/src/services/expression_compiler_service.dart
@@ -27,14 +27,22 @@ class _Compiler {
 
   /// Sends [request] on [_sendPort] and returns the next event from the
   /// response stream.
-  Future<Map<String, Object>> _send(Map<String, Object> request) async {
+  Future<Map<String, dynamic>> _send(Map<String, Object> request) async {
     _sendPort.send(request);
-    return await _responseQueue.hasNext
-        ? Map<String, Object>.from(await _responseQueue.next)
-        : {
-            'succeeded': false,
-            'errors': ['compilation service response stream closed'],
-          };
+    if (!await _responseQueue.hasNext) {
+      return {
+        'succeeded': false,
+        'errors': ['compilation worker response stream closed'],
+      };
+    }
+    final response = await _responseQueue.next;
+    if (response is! Map<String, dynamic>) {
+      return {
+        'succeeded': false,
+        'errors': ['compilation worker returned invalid response: $response'],
+      };
+    }
+    return response;
   }
 
   /// Starts expression compilation service.
@@ -46,11 +54,11 @@ class _Compiler {
   /// expression compilation (summaries, libraries spec, compiler worker
   /// snapshot).
   ///
-  /// [soundNullSafety] indiciates if the compioler should support sound null
-  /// safety.
+  /// [soundNullSafety] indicates if the compiler should support sound
+  /// null safety.
   ///
   /// Performs handshake with the isolate running expression compiler
-  /// worker to estabish communication via send/receive ports, returns
+  /// worker to establish communication via send/receive ports, returns
   /// the service after the communication is established.
   ///
   /// Users need to stop the service by calling [stop].
@@ -131,9 +139,12 @@ class _Compiler {
     if (result) {
       _logger.info('Updated dependencies.');
     } else {
-      final e = response['exception'];
-      final s = response['stackTrace'];
-      _logger.severe('Failed to update dependencies: $e:$s');
+      final errors = response['errors'];
+      final exception = response['exception'];
+      final s = response['stackTrace'] as String?;
+      final stackTrace = s == null ? null : StackTrace.fromString(s);
+      _logger.severe(
+          'Failed to update dependencies: $errors', exception, stackTrace);
     }
     updateCompleter.complete();
     return result;
diff --git a/dwds/test/expression_compiler_service_test.dart b/dwds/test/expression_compiler_service_test.dart
index 5004f0e59..ab873b847 100644
--- a/dwds/test/expression_compiler_service_test.dart
+++ b/dwds/test/expression_compiler_service_test.dart
@@ -55,8 +55,11 @@ void main() async {
       output.stream.listen(printOnFailure);
 
       configureLogWriter(
-          customLogWriter: (level, message, {error, loggerName, stackTrace}) =>
-              output.add('[$level] $loggerName: $message'));
+          customLogWriter: (level, message, {error, loggerName, stackTrace}) {
+        final e = error == null ? '' : ': $error';
+        final s = stackTrace == null ? '' : ':\n$stackTrace';
+        output.add('[$level] $loggerName: $message$e$s');
+      });
 
       // start asset server
       _server = await startHttpServer('localhost');
@@ -147,7 +150,6 @@ void main() async {
               '[FINEST] ExpressionCompilerService: Compiled "true" to:')));
       expect(output.stream,
           emitsThrough(contains('[INFO] ExpressionCompilerService: Stopped.')));
-
       final result = await service
           .updateDependencies({'try': ModuleInfo('try.full.dill', 'try.dill')});
       expect(result, true, reason: 'failed to update dependencies');