diff --git a/pkg/front_end/test/fasta/testing/suite.dart b/pkg/front_end/test/fasta/testing/suite.dart
index 2540ddded6c..ed80870c89f 100644
--- a/pkg/front_end/test/fasta/testing/suite.dart
+++ b/pkg/front_end/test/fasta/testing/suite.dart
@@ -153,6 +153,9 @@ export 'package:testing/testing.dart' show Chain, runMe;
 
 const String ENABLE_FULL_COMPILE = " full compile ";
 
+const String UPDATE_EXPECTATIONS = "updateExpectations";
+const String UPDATE_COMMENTS = "updateComments";
+
 const String EXPECTATIONS = '''
 [
   {
@@ -289,6 +292,9 @@ class FastaContext extends ChainContext with MatchContext {
   @override
   final bool updateExpectations;
 
+  @override
+  String get updateExpectationsOption => '${UPDATE_EXPECTATIONS}=true';
+
   @override
   final ExpectationSet expectationSet =
       new ExpectationSet.fromJsonList(jsonDecode(EXPECTATIONS));
@@ -687,8 +693,8 @@ class FastaContext extends ChainContext with MatchContext {
     bool weak = environment["weak"] == "true";
     bool onlyCrashes = environment["onlyCrashes"] == "true";
     bool ignoreExpectations = environment["ignoreExpectations"] == "true";
-    bool updateExpectations = environment["updateExpectations"] == "true";
-    bool updateComments = environment["updateComments"] == "true";
+    bool updateExpectations = environment[UPDATE_EXPECTATIONS] == "true";
+    bool updateComments = environment[UPDATE_COMMENTS] == "true";
     bool skipVm = environment["skipVm"] == "true";
     bool verify = environment["verify"] != "false";
     bool kernelTextSerialization =
@@ -1098,7 +1104,8 @@ class Outline extends Step<TestDescription, ComponentResult, FastaContext> {
                     description, p, userLibraries, options, sourceTarget),
                 context.expectationSet["InstrumentationMismatch"],
                 instrumentation.problemsAsString,
-                null);
+                null,
+                autoFixCommand: '${UPDATE_COMMENTS}=true');
           }
         }
       }
diff --git a/pkg/front_end/test/fasta/textual_outline_suite.dart b/pkg/front_end/test/fasta/textual_outline_suite.dart
index db5dda5c709..aeb3343c551 100644
--- a/pkg/front_end/test/fasta/textual_outline_suite.dart
+++ b/pkg/front_end/test/fasta/textual_outline_suite.dart
@@ -22,6 +22,7 @@ import 'package:testing/testing.dart'
         runMe;
 
 import '../utils/kernel_chain.dart' show MatchContext;
+import 'testing/suite.dart' show UPDATE_EXPECTATIONS;
 
 const List<Map<String, String>> EXPECTATIONS = [
   {
@@ -52,6 +53,10 @@ main([List<String> arguments = const []]) =>
 
 class Context extends ChainContext with MatchContext {
   final bool updateExpectations;
+
+  @override
+  String get updateExpectationsOption => '${UPDATE_EXPECTATIONS}=true';
+
   Context(this.updateExpectations);
 
   final List<Step> steps = const <Step>[
diff --git a/pkg/front_end/test/parser_suite.dart b/pkg/front_end/test/parser_suite.dart
index 632e9eea382..79145fbff75 100644
--- a/pkg/front_end/test/parser_suite.dart
+++ b/pkg/front_end/test/parser_suite.dart
@@ -46,6 +46,7 @@ import 'package:testing/testing.dart'
         TestDescription,
         runMe;
 
+import 'fasta/testing/suite.dart' show UPDATE_EXPECTATIONS;
 import 'utils/kernel_chain.dart' show MatchContext;
 
 import 'parser_test_listener.dart' show ParserTestListener;
@@ -86,6 +87,10 @@ ScannerConfiguration scannerConfigurationNonNNBD = new ScannerConfiguration(
 
 class Context extends ChainContext with MatchContext {
   final bool updateExpectations;
+
+  @override
+  String get updateExpectationsOption => '${UPDATE_EXPECTATIONS}=true';
+
   final bool addTrace;
   final bool annotateLines;
   final String suiteName;
diff --git a/pkg/front_end/test/unit_test_suites.dart b/pkg/front_end/test/unit_test_suites.dart
index 1f420476422..c106ebf11a5 100644
--- a/pkg/front_end/test/unit_test_suites.dart
+++ b/pkg/front_end/test/unit_test_suites.dart
@@ -45,9 +45,10 @@ class Options {
   final bool printFailureLog;
   final Uri outputDirectory;
   final String testFilter;
+  final List<String> environmentOptions;
 
   Options(this.configurationName, this.verbose, this.printFailureLog,
-      this.outputDirectory, this.testFilter);
+      this.outputDirectory, this.testFilter, this.environmentOptions);
 
   static Options parse(List<String> args) {
     var parser = new ArgParser()
@@ -59,7 +60,9 @@ class Options {
       ..addFlag("verbose",
           abbr: "v", help: "print additional information", defaultsTo: false)
       ..addFlag("print",
-          abbr: "p", help: "print failure logs", defaultsTo: false);
+          abbr: "p", help: "print failure logs", defaultsTo: false)
+      ..addMultiOption('environment',
+          abbr: 'D', help: "environment options for the test suite");
     var parsedArguments = parser.parse(args);
     String outputPath = parsedArguments["output-directory"] ?? ".";
     Uri outputDirectory = Uri.base.resolveUri(Uri.directory(outputPath));
@@ -75,7 +78,8 @@ class Options {
         parsedArguments["verbose"],
         parsedArguments["print"],
         outputDirectory,
-        filter);
+        filter,
+        parsedArguments['environment']);
   }
 }
 
@@ -142,8 +146,17 @@ class ResultLogger implements Logger {
       if (result.trace != null) {
         failureLog = "$failureLog\n\n${result.trace}";
       }
-      failureLog = "$failureLog\n\nRe-run this test: dart "
-          "pkg/front_end/test/unit_test_suites.dart -p $testName";
+      if (result.autoFixCommand != null) {
+        failureLog = "$failureLog\n\n"
+            "To re-run this test, run:\n\n"
+            "   dart pkg/front_end/test/unit_test_suites.dart -p $testName\n\n"
+            "To automatically update the test expectations, run:\n\n"
+            "   dart pkg/front_end/test/unit_test_suites.dart -p $testName "
+            "-D${result.autoFixCommand}\n";
+      } else {
+        failureLog = "$failureLog\n\nRe-run this test: dart "
+            "pkg/front_end/test/unit_test_suites.dart -p $testName";
+      }
       String outcome = "${result.outcome}";
       logsPort.send(jsonEncode({
         "name": testName,
@@ -287,6 +300,8 @@ class SuiteConfiguration {
   final bool printFailureLog;
   final String configurationName;
   final String testFilter;
+  final List<String> environmentOptions;
+
   const SuiteConfiguration(
       this.name,
       this.resultsPort,
@@ -294,7 +309,8 @@ class SuiteConfiguration {
       this.verbose,
       this.printFailureLog,
       this.configurationName,
-      this.testFilter);
+      this.testFilter,
+      this.environmentOptions);
 }
 
 void runSuite(SuiteConfiguration configuration) {
@@ -312,9 +328,11 @@ void runSuite(SuiteConfiguration configuration) {
       configuration.verbose,
       configuration.printFailureLog,
       configuration.configurationName);
-  runMe(
-      <String>[if (configuration.testFilter != null) configuration.testFilter],
-      suite.createContext,
+  runMe(<String>[
+    if (configuration.testFilter != null) configuration.testFilter,
+    if (configuration.environmentOptions != null)
+      for (String option in configuration.environmentOptions) '-D${option}',
+  ], suite.createContext,
       me: suiteUri,
       configurationPath: suite.testingRootPath,
       logger: logger,
@@ -359,7 +377,8 @@ main([List<String> arguments = const <String>[]]) async {
         options.verbose,
         options.printFailureLog,
         options.configurationName,
-        filter);
+        filter,
+        options.environmentOptions);
     Future future = Future<bool>(() async {
       Stopwatch stopwatch = Stopwatch()..start();
       print("Running suite $name");
diff --git a/pkg/front_end/test/utils/kernel_chain.dart b/pkg/front_end/test/utils/kernel_chain.dart
index d530ed8de31..804af3cf00d 100644
--- a/pkg/front_end/test/utils/kernel_chain.dart
+++ b/pkg/front_end/test/utils/kernel_chain.dart
@@ -66,6 +66,8 @@ final Uri platformBinariesLocation = computePlatformBinariesLocation();
 abstract class MatchContext implements ChainContext {
   bool get updateExpectations;
 
+  String get updateExpectationsOption;
+
   ExpectationSet get expectationSet;
 
   Expectation get expectationFileMismatch =>
@@ -93,7 +95,10 @@ abstract class MatchContext implements ChainContext {
         String diff = await runDiff(expectedFile.uri, actual);
         onMismatch ??= expectationFileMismatch;
         return new Result<O>(output, onMismatch,
-            "$uri doesn't match ${expectedFile.uri}\n$diff", null);
+            "$uri doesn't match ${expectedFile.uri}\n$diff", null,
+            autoFixCommand: onMismatch == expectationFileMismatch
+                ? updateExpectationsOption
+                : null);
       } else {
         return new Result<O>.pass(output);
       }
@@ -108,7 +113,8 @@ abstract class MatchContext implements ChainContext {
           """
 Please create file ${expectedFile.path} with this content:
 $actual""",
-          null);
+          null,
+          autoFixCommand: updateExpectationsOption);
     }
   }
 
diff --git a/pkg/front_end/testcases/inference_new/const_invocation.dart b/pkg/front_end/testcases/inference_new/const_invocation.dart
index 85251743edf..4e58d44822f 100644
--- a/pkg/front_end/testcases/inference_new/const_invocation.dart
+++ b/pkg/front_end/testcases/inference_new/const_invocation.dart
@@ -8,7 +8,7 @@ library test;
 typedef V F<U, V>(U u);
 
 class Foo<T> {
-  Bar<T> get v1 => const /*@ typeArgs=Null? */ Bar();
+  Bar<T> get v1 => const /*@typeArgs=Null?*/ Bar();
   Bar<List<T>> get v2 => const /*@ typeArgs=List<Null?>* */ Bar();
   Bar<F<T, T>> get v3 => const /*@ typeArgs=(Object*) ->* Null? */ Bar();
   Bar<F<F<T, T>, T>> get v4 =>
diff --git a/pkg/testing/lib/src/chain.dart b/pkg/testing/lib/src/chain.dart
index e51bcb45e2b..a6c982d4e79 100644
--- a/pkg/testing/lib/src/chain.dart
+++ b/pkg/testing/lib/src/chain.dart
@@ -354,7 +354,12 @@ class Result<O> {
 
   final List<String> logs = <String>[];
 
-  Result(this.output, this.outcome, this.error, this.trace);
+  /// If set, running the test with '-D$autoFixCommand' will automatically
+  /// update the test to match new expectations.
+  final String autoFixCommand;
+
+  Result(this.output, this.outcome, this.error, this.trace,
+      {this.autoFixCommand});
 
   Result.pass(O output) : this(output, Expectation.Pass, null, null);