Add return types on all main declarations

Reduces the noise when disallowing implicit dynamic.

Change-Id: I98b03cb675ecd4b9e7f4135efa274fb57eb87832
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/104164
Reviewed-by: Nicholas Shahan <nshahan@google.com>
Commit-Queue: Nate Bosch <nbosch@google.com>
diff --git a/pkg/dev_compiler/test/js/builder_test.dart b/pkg/dev_compiler/test/js/builder_test.dart
index d294048..0dfae14 100644
--- a/pkg/dev_compiler/test/js/builder_test.dart
+++ b/pkg/dev_compiler/test/js/builder_test.dart
@@ -13,7 +13,7 @@
 
 _checkExpression(String src) => _check(_parser(src).parseExpression(), src);
 
-main() {
+void main() {
   group('MiniJsParser', () {
     // TODO(ochafik): Add more coverage.
     test('parses classes with complex members', () {
diff --git a/pkg/dev_compiler/test/options/options_test.dart b/pkg/dev_compiler/test/options/options_test.dart
index 3f5b3b1..7f78142 100644
--- a/pkg/dev_compiler/test/options/options_test.dart
+++ b/pkg/dev_compiler/test/options/options_test.dart
@@ -24,7 +24,7 @@
 
 final sdkSummaryArgs = ['--$sdkSummaryPathOption', sdkSummaryFile];
 
-main() {
+void main() {
   test('basic', () {
     var options = AnalyzerOptions.basic()..analysisRoot = optionsDir;
     var driver = CompilerAnalysisDriver(options);
diff --git a/pkg/dev_compiler/test/sourcemap/sourcemaps_ddc_suite.dart b/pkg/dev_compiler/test/sourcemap/sourcemaps_ddc_suite.dart
index 3818d6f..275870c 100644
--- a/pkg/dev_compiler/test/sourcemap/sourcemaps_ddc_suite.dart
+++ b/pkg/dev_compiler/test/sourcemap/sourcemaps_ddc_suite.dart
@@ -85,4 +85,5 @@
   }
 }
 
-main(List<String> arguments) => runMe(arguments, createContext, "testing.json");
+void main(List<String> arguments) =>
+    runMe(arguments, createContext, "testing.json");
diff --git a/pkg/dev_compiler/test/sourcemap/sourcemaps_ddk_suite.dart b/pkg/dev_compiler/test/sourcemap/sourcemaps_ddk_suite.dart
index 511c10b..1d1fb94 100644
--- a/pkg/dev_compiler/test/sourcemap/sourcemaps_ddk_suite.dart
+++ b/pkg/dev_compiler/test/sourcemap/sourcemaps_ddk_suite.dart
@@ -104,4 +104,5 @@
   }
 }
 
-main(List<String> arguments) => runMe(arguments, createContext, "testing.json");
+void main(List<String> arguments) =>
+    runMe(arguments, createContext, "testing.json");
diff --git a/pkg/dev_compiler/test/sourcemap/stacktrace_ddc_suite.dart b/pkg/dev_compiler/test/sourcemap/stacktrace_ddc_suite.dart
index 1143568..d137aa1 100644
--- a/pkg/dev_compiler/test/sourcemap/stacktrace_ddc_suite.dart
+++ b/pkg/dev_compiler/test/sourcemap/stacktrace_ddc_suite.dart
@@ -19,4 +19,5 @@
   ];
 }
 
-main(List<String> arguments) => runMe(arguments, createContext, "testing.json");
+void main(List<String> arguments) =>
+    runMe(arguments, createContext, "testing.json");
diff --git a/pkg/dev_compiler/test/sourcemap/stacktrace_ddk_suite.dart b/pkg/dev_compiler/test/sourcemap/stacktrace_ddk_suite.dart
index aeaca51..94d26c6 100644
--- a/pkg/dev_compiler/test/sourcemap/stacktrace_ddk_suite.dart
+++ b/pkg/dev_compiler/test/sourcemap/stacktrace_ddk_suite.dart
@@ -28,4 +28,5 @@
   }
 }
 
-main(List<String> arguments) => runMe(arguments, createContext, "testing.json");
+void main(List<String> arguments) =>
+    runMe(arguments, createContext, "testing.json");
diff --git a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/null_instance_field.dart b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/null_instance_field.dart
index a624b2e..131d057 100644
--- a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/null_instance_field.dart
+++ b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/null_instance_field.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   /*1:main*/ test(Class());
 }
 
diff --git a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/null_interceptor_field.dart b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/null_interceptor_field.dart
index 21fc03c..beec13d 100644
--- a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/null_interceptor_field.dart
+++ b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/null_interceptor_field.dart
@@ -6,7 +6,7 @@
   get length => 3; // ensures we build an interceptor for `.length`
 }
 
-main() {
+void main() {
   confuse('').trim(); // includes some code above the interceptors
   confuse([]).length;
   confuse(MyType()).length;
diff --git a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/rethrow.dart b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/rethrow.dart
index 2354061..82a3819 100644
--- a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/rethrow.dart
+++ b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/rethrow.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   /*1:main*/ test();
 }
 
diff --git a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_async.dart b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_async.dart
index 0f6165e..ea6ab10 100644
--- a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_async.dart
+++ b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_async.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   /*1:main*/ test();
 }
 
diff --git a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_awaited_async.dart b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_awaited_async.dart
index 2801397..5e4721a 100644
--- a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_awaited_async.dart
+++ b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_awaited_async.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   /*1:main*/ test1();
 }
 
diff --git a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_constructor.dart b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_constructor.dart
index fde3136..f57db8f 100644
--- a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_constructor.dart
+++ b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_constructor.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   // ignore: UNUSED_LOCAL_VARIABLE
   var /*ddc.1:main*/ c = /*ddk.1:main*/ Class();
 }
diff --git a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_constructor_from_async.dart b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_constructor_from_async.dart
index 907777c..6d251e8 100644
--- a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_constructor_from_async.dart
+++ b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_constructor_from_async.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   // This call is no longer on the stack when the error is thrown.
   /*1:main*/ test();
 }
diff --git a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_instance_method.dart b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_instance_method.dart
index 4261c48..2fbc97f 100644
--- a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_instance_method.dart
+++ b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_instance_method.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   var c = Class();
   c. /*1:main*/ test();
 }
diff --git a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_main.dart b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_main.dart
index f43b4d4..c7043fe 100644
--- a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_main.dart
+++ b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_main.dart
@@ -2,6 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   /*1:main*/ throw '>ExceptionMarker<';
 }
diff --git a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_static_method.dart b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_static_method.dart
index 4c4e5b8..658db6a 100644
--- a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_static_method.dart
+++ b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_static_method.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   /*ddc.1:main*/ Class. /*ddk.1:main*/ test();
 }
 
diff --git a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_top_level_method.dart b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_top_level_method.dart
index 962e60c..d03d29a 100644
--- a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_top_level_method.dart
+++ b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_top_level_method.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   /*1:main*/ test();
 }
 
diff --git a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_top_level_method_from_async.dart b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_top_level_method_from_async.dart
index f58dde6..f5240ee 100644
--- a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_top_level_method_from_async.dart
+++ b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_top_level_method_from_async.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   /*1:main*/ test1();
 }
 
diff --git a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_try_catch.dart b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_try_catch.dart
index 2bb8501..1da6f77 100644
--- a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_try_catch.dart
+++ b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_try_catch.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   /*1:main*/ test();
 }
 
diff --git a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_try_finally.dart b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_try_finally.dart
index fe97b70..7bfcd1a 100644
--- a/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_try_finally.dart
+++ b/pkg/dev_compiler/test/sourcemap/stacktrace_testfiles/throw_in_try_finally.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   /*1:main*/ test();
 }
 
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/breakpoint_on_function_line_breaks_in_body.dart b/pkg/dev_compiler/test/sourcemap/testfiles/breakpoint_on_function_line_breaks_in_body.dart
index c133da3..e7f354b 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/breakpoint_on_function_line_breaks_in_body.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/breakpoint_on_function_line_breaks_in_body.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   foo();
 }
 
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/call_on_field_in_class.dart b/pkg/dev_compiler/test/sourcemap/testfiles/call_on_field_in_class.dart
index 69b242d..567e68e 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/call_on_field_in_class.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/call_on_field_in_class.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   /* bl */ var foo = /*sl:1*/ Foo();
   foo.foo = foo. /*sl:2*/ fooMethod;
   foo /*sl:3*/ .fooMethod();
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/hello_async.dart b/pkg/dev_compiler/test/sourcemap/testfiles/hello_async.dart
index 6758e46..cfa5b12 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/hello_async.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/hello_async.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   /*bl*/
   /*s:1*/ foo();
   /*s:4*/
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/hello_call.dart b/pkg/dev_compiler/test/sourcemap/testfiles/hello_call.dart
index 0d3d2e4..a5662bb 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/hello_call.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/hello_call.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   /*bl*/
   /*s:1*/ foo();
 }
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/hello_class_call.dart b/pkg/dev_compiler/test/sourcemap/testfiles/hello_class_call.dart
index 31e4aa7..de068a9 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/hello_class_call.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/hello_class_call.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   /*bl*/
   Foo foo = Foo();
   foo.foo();
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/hello_sane_column_on_print_return_value.dart b/pkg/dev_compiler/test/sourcemap/testfiles/hello_sane_column_on_print_return_value.dart
index 6c1b07afa..49408f2 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/hello_sane_column_on_print_return_value.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/hello_sane_column_on_print_return_value.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   /*bc:3*/ print(/*bc:1*/ foo());
 }
 
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/hello_world.dart b/pkg/dev_compiler/test/sourcemap/testfiles/hello_world.dart
index 59746a1..019e2de 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/hello_world.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/hello_world.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   /*nb*/ // no break on empty line
   /*bl*/ print("Hello, World!");
 /*s:1*/
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/method_call_with_named_parameters.dart b/pkg/dev_compiler/test/sourcemap/testfiles/method_call_with_named_parameters.dart
index 426e385..f665d7c 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/method_call_with_named_parameters.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/method_call_with_named_parameters.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   foo(/*bc:1*/ bar(), baz: /*bc:2*/ baz());
   /*nbb:0:4*/
 }
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/method_call_with_named_parameters_no_given.dart b/pkg/dev_compiler/test/sourcemap/testfiles/method_call_with_named_parameters_no_given.dart
index 6091682..763d098 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/method_call_with_named_parameters_no_given.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/method_call_with_named_parameters_no_given.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   foo(/*bc:1*/ bar());
   /*nbb:0:3*/
 }
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_assert.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_assert.dart
index 0b692fa..bcf0307 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_assert.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_assert.dart
@@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 /*Debugger:stepOver*/
-main() {
+void main() {
   assert(/*bc:1*/ foo());
 }
 
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_assign_call_test.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_assign_call_test.dart
index f44926d..b4941e7 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_assign_call_test.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_assign_call_test.dart
@@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 /*Debugger:stepOver*/
-main() {
+void main() {
   /*nb*/ int a;
   /*nb*/ int b;
   a = b = /*bc:1*/ foo();
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_assign_int_test.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_assign_int_test.dart
index bed6ec6..5a4452e 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_assign_int_test.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_assign_int_test.dart
@@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 /*Debugger:stepOver*/
-main() {
+void main() {
   /*nb*/ int a;
   /*nb*/ int b;
   /*bl*/
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_catch_test.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_catch_test.dart
index 777af94..fe9fde0 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_catch_test.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_catch_test.dart
@@ -4,7 +4,7 @@
 
 /*Debugger:stepOver*/
 
-main() {
+void main() {
   /*bl*/
   try {
     /*sl:1*/ var value = "world";
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_for_each_loop_test.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_for_each_loop_test.dart
index 112a8fb..d59f77b 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_for_each_loop_test.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_for_each_loop_test.dart
@@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 /*Debugger:stepOver*/
-main() {
+void main() {
   /*bl*/ /*sl:1*/ List<int> data = [1, 2, 3];
   for (
       // comment forcing formatting
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_for_loop_with_break_and_continue_test.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_for_loop_with_break_and_continue_test.dart
index c51f64f..f562c22 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_for_loop_with_break_and_continue_test.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_for_loop_with_break_and_continue_test.dart
@@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 /*Debugger:stepOver*/
-main() {
+void main() {
   /*bl*/ /*sl:1*/ int count = 0;
   for (/*sl:2*/ int i = 0;
       /*sl:3*/ /*sl:8*/ /*sl:13*/ /*sl:17*/ /*nbb:18:21*/ i < 42;
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_is_and_as_test.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_is_and_as_test.dart
index d3b49d1..2f90736 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_is_and_as_test.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_is_and_as_test.dart
@@ -4,7 +4,7 @@
 
 /*Debugger:stepOver*/
 
-main() {
+void main() {
   /*bl*/
   /*sl:1*/ var i = 42.42;
   /*sl:2*/ var hex = 0x42;
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_map_creation.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_map_creation.dart
index 83e19bb..8d38e83 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_map_creation.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_map_creation.dart
@@ -4,7 +4,7 @@
 
 /*Debugger:stepOver*/
 
-main() {
+void main() {
   /*bl*/
   var x = {/*bc:1*/ foo(): /*bc:2*/ bar() };
   /*sl:3*/ print(x);
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_multi_catch_test.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_multi_catch_test.dart
index e2c30d0..d2ecc4c 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_multi_catch_test.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_multi_catch_test.dart
@@ -4,7 +4,7 @@
 
 /*Debugger:stepOver*/
 
-main() {
+void main() {
   /*bl*/
   try {
     /*sl:1*/ throw "Boom!";
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_operator_bracket_on_super_test.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_operator_bracket_on_super_test.dart
index 27d4995..de8c40d 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_operator_bracket_on_super_test.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_operator_bracket_on_super_test.dart
@@ -21,7 +21,7 @@
   }
 }
 
-main() {
+void main() {
   Class3 c = Class3();
   c[42];
   c.code();
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_operator_bracket_on_this_test.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_operator_bracket_on_this_test.dart
index d529139..f0f1130 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_operator_bracket_on_this_test.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_operator_bracket_on_this_test.dart
@@ -13,7 +13,7 @@
   }
 }
 
-main() {
+void main() {
   Class2 c = Class2();
   c[42];
   c.code();
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_operator_bracket_test.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_operator_bracket_test.dart
index c3d7835..90fa680 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_operator_bracket_test.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_operator_bracket_test.dart
@@ -13,7 +13,7 @@
   }
 }
 
-main() {
+void main() {
   /*bl*/ /*sl:1*/ Class2 c = Class2();
   c /*sl:2*/ [42];
   c /*sl:3*/ .code();
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_static_set.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_static_set.dart
index a621285..7bdd6e4 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_static_set.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_static_set.dart
@@ -6,7 +6,7 @@
 
 var bar = 0;
 
-main() {
+void main() {
   bar = /*bc:1*/ foo();
 }
 
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_string_concatenation.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_string_concatenation.dart
index 38c5aa5..610c2aa 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_string_concatenation.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_string_concatenation.dart
@@ -4,7 +4,7 @@
 
 /*Debugger:stepOver*/
 
-main() {
+void main() {
   var qux;
   qux = "${/*bc:1*/ foo()} x ${/*bc:2*/ bar()} x ${/*bc:3*/ baz()}";
   print(qux);
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_string_plus.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_string_plus.dart
index 382044e..bc5d2f5 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_string_plus.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_string_plus.dart
@@ -4,7 +4,7 @@
 
 /*Debugger:stepOver*/
 
-main() {
+void main() {
   var qux;
   qux = /*bc:1*/ foo() + /*bc:2*/ bar();
   print(qux);
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_throw.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_throw.dart
index 586d52d..1d7b275 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_throw.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_throw.dart
@@ -4,7 +4,7 @@
 
 /*Debugger:stepOver*/
 
-main() {
+void main() {
   try {
     throw /*bc:1*/ foo();
   } catch (e) {
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_variable_set.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_variable_set.dart
index 50177f2..54e362b 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_variable_set.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_variable_set.dart
@@ -4,7 +4,7 @@
 
 /*Debugger:stepOver*/
 
-main() {
+void main() {
   /*bl*/
   /*sl:1*/ var x = 0;
   x = /*bc:2*/ foo();
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_yield.dart b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_yield.dart
index 05ca943..882e28c 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/next_through_yield.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/next_through_yield.dart
@@ -4,7 +4,7 @@
 
 /*Debugger:stepOver*/
 
-main() {
+void main() {
   for (int i in naturalsTo(2)) {
     print(i);
   }
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_class_constructor_line.dart b/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_class_constructor_line.dart
index f6b3b13..aa521b6 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_class_constructor_line.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_class_constructor_line.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   // ignore: unused_local_variable
   Foo foo = Foo();
 }
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_class_function_line.dart b/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_class_function_line.dart
index 26508de..33ea7c2 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_class_function_line.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_class_function_line.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   Foo foo = Foo();
   foo.foo();
 }
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_class_line.dart b/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_class_line.dart
index 0233caa4..d64c1fa 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_class_line.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_class_line.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   Foo foo = Foo();
   foo.foo();
 }
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_class_named_constructor_line.dart b/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_class_named_constructor_line.dart
index 32ddfc4..22930ce 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_class_named_constructor_line.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_class_named_constructor_line.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   // ignore: unused_local_variable
   Foo foo = Foo.named();
 }
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_function_line.dart b/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_function_line.dart
index 48223d1..a80c41e 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_function_line.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/no_mapping_on_function_line.dart
@@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 /*nm*/
-main() {
+void main() {
   foo();
 }
 
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/printing_class_fields.dart b/pkg/dev_compiler/test/sourcemap/testfiles/printing_class_fields.dart
index 8bf01a3..0d94442 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/printing_class_fields.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/printing_class_fields.dart
@@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 /*Debugger:stepOver*/
-main() {
+void main() {
   /*bl*/
   /*sl:1*/ Foo foo = Foo(1, 2);
   /*sl:2*/ print(foo.x);
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/printing_class_fields_step_into.dart b/pkg/dev_compiler/test/sourcemap/testfiles/printing_class_fields_step_into.dart
index f3f17c1..e889171 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/printing_class_fields_step_into.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/printing_class_fields_step_into.dart
@@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 /*nb*/
-main() {
+void main() {
   /*bl*/
   Foo foo = /*sl:1*/ Foo(1, 2);
   /*s:5*/ print(foo.x);
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/step_through_async_star_yield.dart b/pkg/dev_compiler/test/sourcemap/testfiles/step_through_async_star_yield.dart
index ec3cab3..36bd4ef 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/step_through_async_star_yield.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/step_through_async_star_yield.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() async {
+void main() async {
   await for (var i in foobar()) {
     print(i);
   }
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/step_through_await_for.dart b/pkg/dev_compiler/test/sourcemap/testfiles/step_through_await_for.dart
index e2021cf..e5b6d10 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/step_through_await_for.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/step_through_await_for.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() async {
+void main() async {
   /* bl */
   /*sl:1 */ print("About to loop!");
   await for (var /*s:3*/ /*s:5*/ i in foobar /*sl:2*/ ()) {
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/step_through_conditional_expression.dart b/pkg/dev_compiler/test/sourcemap/testfiles/step_through_conditional_expression.dart
index 8ea00cf..867c480 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/step_through_conditional_expression.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/step_through_conditional_expression.dart
@@ -4,7 +4,7 @@
 
 /*Debugger:stepOver*/
 
-main() {
+void main() {
   print(/*bc:1*/ foo() ? bar() : /*bc:2*/ baz());
   print(/*bc:4*/ ! /*bc:3*/ foo() ? /*bc:5*/ bar() : baz());
 }
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/step_through_if_and_identical.dart b/pkg/dev_compiler/test/sourcemap/testfiles/step_through_if_and_identical.dart
index 0b81376..7984135 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/step_through_if_and_identical.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/step_through_if_and_identical.dart
@@ -4,7 +4,7 @@
 
 /*Debugger:stepOver*/
 
-main() {
+void main() {
   if (/*bc:1*/ foo() == /*bc:2*/ bar()) {
     print("wat?!?");
   }
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/step_through_property_get_test.dart b/pkg/dev_compiler/test/sourcemap/testfiles/step_through_property_get_test.dart
index e4211c0..78826c7 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/step_through_property_get_test.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/step_through_property_get_test.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   Bar bar = Bar();
   bar.doStuff();
 }
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/step_through_sync_star.dart b/pkg/dev_compiler/test/sourcemap/testfiles/step_through_sync_star.dart
index 84bb777..36768c1 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/step_through_sync_star.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/step_through_sync_star.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   /* bl */
   /*sl:1*/ var iterator = naturalsTo(2);
   for (int /*bc:3*/ /*bc:8*/ /*bc:12*/ i in /*bc:2*/ iterator) {
diff --git a/pkg/dev_compiler/test/sourcemap/testfiles/stops_at_ending_brace.dart b/pkg/dev_compiler/test/sourcemap/testfiles/stops_at_ending_brace.dart
index 8bcca4b..d322e4c 100644
--- a/pkg/dev_compiler/test/sourcemap/testfiles/stops_at_ending_brace.dart
+++ b/pkg/dev_compiler/test/sourcemap/testfiles/stops_at_ending_brace.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-main() {
+void main() {
   Foo();
   // Comment to push the ending brace back a bit.
 /*s:2*/
diff --git a/pkg/dev_compiler/test/string_to_uri_test.dart b/pkg/dev_compiler/test/string_to_uri_test.dart
index 31b86f6..063b87a 100755
--- a/pkg/dev_compiler/test/string_to_uri_test.dart
+++ b/pkg/dev_compiler/test/string_to_uri_test.dart
@@ -2,7 +2,7 @@
 import 'package:dev_compiler/src/compiler/shared_command.dart';
 import 'package:test/test.dart';
 
-main(List<String> args) {
+void main(List<String> args) {
   String currentDir;
   setUpAll(() {
     currentDir = Directory.current.path.replaceAll(r'\', r'/');
diff --git a/pkg/dev_compiler/tool/build_sdk.dart b/pkg/dev_compiler/tool/build_sdk.dart
index 5fc97e0..60eb377 100644
--- a/pkg/dev_compiler/tool/build_sdk.dart
+++ b/pkg/dev_compiler/tool/build_sdk.dart
@@ -13,7 +13,7 @@
 
 import 'package:dev_compiler/src/analyzer/command.dart';
 
-main(List<String> arguments) async {
+void main(List<String> arguments) async {
   var args = ['--no-source-map', '--no-emit-metadata'];
   args.addAll(arguments);
   args.addAll([
diff --git a/pkg/dev_compiler/web/main.dart b/pkg/dev_compiler/web/main.dart
index 67a02bd..df7682f 100755
--- a/pkg/dev_compiler/web/main.dart
+++ b/pkg/dev_compiler/web/main.dart
@@ -17,7 +17,7 @@
 external set setUpCompilerInBrowser(Function function);
 
 Future<dynamic> _setUpCompilerInBrowser;
-main() {
+void main() {
   var args = ['compile'];
 
   // Avoid race condition when users try to call $setUpDartDevCompilerInBrowser
diff --git a/pkg/dev_compiler/web/stack_trace_mapper.dart b/pkg/dev_compiler/web/stack_trace_mapper.dart
index 9044aa6..7fa1dc1 100644
--- a/pkg/dev_compiler/web/stack_trace_mapper.dart
+++ b/pkg/dev_compiler/web/stack_trace_mapper.dart
@@ -112,7 +112,7 @@
   _mapping = LazyMapping(provider);
 }
 
-main() {
+void main() {
   // Register with DDC.
   dartStackTraceUtility = DartStackTraceUtility(
       mapper: allowInterop(mapper),