Deprecate all diagnostics methods that use strings.

pkg/front_end/lib/src/fasta/compiler_command_line.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // 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.
 
 library fasta.compiler_command_line;
 
 import 'dart:io' show exit;
 
-import 'command_line.dart' show CommandLine, argumentError;
+import 'command_line.dart' show CommandLine, deprecated_argumentError;
 
 import 'compiler_context.dart' show CompilerContext;
 
 import 'package:kernel/target/targets.dart'
     show Target, getTarget, TargetFlags, targets;
 
 const Map<String, dynamic> optionSpecification = const <String, dynamic>{
   "--compile-sdk": Uri,
   "--fatal": ",",
   "--output": Uri,
@@ skipping 27 matching lines @@
         options.containsKey("/?");
   }
 
   void validate() {
     if (help) {
       print(computeUsage(programName, verbose));
       exit(0);
     }
 
     if (options.containsKey("-o") && options.containsKey("--output")) {
-      return argumentError(usage, "Can't specify both '-o' and '--output'.");
+      return deprecated_argumentError(
+          usage, "Can't specify both '-o' and '--output'.");
     }
     if (options.containsKey("-t") && options.containsKey("--target")) {
-      return argumentError(usage, "Can't specify both '-t' and '--target'.");
+      return deprecated_argumentError(
+          usage, "Can't specify both '-t' and '--target'.");
     }
     if (options.containsKey("--compile-sdk") &&
         options.containsKey("--platform")) {
-      return argumentError(
+      return deprecated_argumentError(
           usage, "Can't specify both '--compile-sdk' and '--platform'.");
     }
     if (programName == "compile_platform" && arguments.length != 3) {
-      return argumentError(usage, "Expected three arguments.");
+      return deprecated_argumentError(usage, "Expected three arguments.");
     } else if (arguments.isEmpty) {
-      return argumentError(usage, "No Dart file specified.");
+      return deprecated_argumentError(usage, "No Dart file specified.");
     }
 
     Target target =
         getTarget(targetName, new TargetFlags(strongMode: strongMode));
     if (target == null) {
-      return argumentError(
+      return deprecated_argumentError(
           usage,
           "Target '${targetName}' not recognized. "
           "Valid targets are:\n  ${targets.keys.join("\n  ")}");
     }
     options["target"] = target;
   }
 
   Uri get output {
     return options["-o"] ?? options["--output"] ?? defaultOutput;
   }
@@ skipping 129 matching lines @@
     libraries.
 
   --fatal=errors
   --fatal=warnings
   --fatal=nits
     Makes messages of the given kinds fatal, that is, immediately stop the
     compiler with a non-zero exit-code. In --verbose mode, also display an
     internal stack trace from the compiler. Multiple kinds can be separated by
     commas, for example, --fatal=errors,warnings.
 """;