anchor.diff:    // watch the performance though.
     if (incremental) {
       compiler = await lookupOrBuildNewIncrementalCompiler(
  -        isolateId, sourceFiles, platformKernel);
  +        isolateId, sourceFiles, platformKernel,
  +        suppressWarnings: suppressWarnings);
     } else {
       final FileSystem fileSystem = sourceFiles == null
           ? PhysicalFileSystem.instance
           : _buildFileSystem(sourceFiles);
       compiler = new SingleShotCompiler(fileSystem, platformKernel,
  -        requireMain: sourceFiles == null, strongMode: strong);
  +        requireMain: sourceFiles == null,
  +        strongMode: strong,
  +        suppressWarnings: suppressWarnings);
     }
   
     CompilationResult result;
  
positive.code: 
    CompilerOptions options;
  
    Compiler(this.fileSystem, Uri platformKernel, {this.strongMode: false}) {
      Uri packagesUri = (Platform.packageConfig != null)
          ? Uri.parse(Platform.packageConfig)
          : null;
  
negative.code:           case Severity.nit:
              break;
            case Severity.warning:
              if (!suppressWarnings) stderr.writeln(formatted);
              break;
          }
        };
  