Report messages instead of just printing.

pkg/front_end/lib/src/fasta/fasta.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;
 
 import 'dart:async' show Future;
 
 import 'dart:convert' show JSON;
 
@@ skipping 11 matching lines @@
 
 import 'deprecated_problems.dart'
     show deprecated_InputError, deprecated_inputError;
 
 import 'kernel/kernel_target.dart' show KernelTarget;
 
 import 'dill/dill_target.dart' show DillTarget;
 
 import 'compile_platform.dart' show compilePlatformInternal;
 
+import 'severity.dart' show Severity;
+
 import 'ticker.dart' show Ticker;
 
 import 'uri_translator.dart' show UriTranslator;
 
 const bool summary = const bool.fromEnvironment("summary", defaultValue: false);
 const int iterations = const int.fromEnvironment("iterations", defaultValue: 1);
 
 compileEntryPoint(List<String> arguments) async {
   // Timing results for each iteration
   List<double> elapsedTimes = <double>[];
@@ skipping 30 matching lines @@
         (CompilerContext c) async {
       if (c.options.verbose) {
         print("Building outlines for ${arguments.join(' ')}");
       }
       CompileTask task =
           new CompileTask(c, new Ticker(isVerbose: c.options.verbose));
       return await task.buildOutline(c.options.output);
     });
   } on deprecated_InputError catch (e) {
     exitCode = 1;
-    print(e.deprecated_format());
+    CompilerContext.current
+        .report(deprecated_InputError.toMessage(e), Severity.error);
     return null;
   }
 }
 
 Future<Uri> compile(List<String> arguments) async {
   try {
     return await CompilerCommandLine.withGlobalOptions("compile", arguments,
         (CompilerContext c) async {
       if (c.options.verbose) {
         print("Compiling directly to Kernel: ${arguments.join(' ')}");
       }
       CompileTask task =
           new CompileTask(c, new Ticker(isVerbose: c.options.verbose));
       return await task.compile();
     });
   } on deprecated_InputError catch (e) {
     exitCode = 1;
-    print(e.deprecated_format());
+    CompilerContext.current
+        .report(deprecated_InputError.toMessage(e), Severity.error);
     return null;
   }
 }
 
 class CompileTask {
   final CompilerContext c;
   final Ticker ticker;
 
   CompileTask(this.c, this.ticker);
 
@@ skipping 124 matching lines @@
   final BytesBuilder builder = new BytesBuilder();
 
   void add(List<int> data) {
     builder.add(data);
   }
 
   void close() {
     // Nothing to do.
   }
 }