anchor.diff:        description: 'An optional offset into the source code.')
     int offset;
   }
  +
  +class SourcesRequest {
  +  @ApiProperty(
  +      required: true,
  +      description: 'Map of names to Sources.')
  +  Map<String, String> sources;
  +
  +  @ApiProperty(
  +      description: 'An optional location in the source code.')
  +  Location location;
  +}
  +
  +class Location {
  +  String fullName;
  +  int offset;
  +
  +  Location(this.fullName, this.offset);
  +}
  +
   
   class CompileRequest {
     @ApiProperty(
  
positive.code:   final String kind;
    final int line;
    final String message;
  
    final bool hasFixes;
  
  
negative.code: 
    AnalysisIssue() : this.fromIssue("", 0, "");
    AnalysisIssue.fromIssue(this.kind, this.line, this.message,
        {this.charStart, this.charLength, this.location,
        this.fullName, this.hasFixes: false});
  
    Map toMap() {
      Map m = {'kind': kind, 'line': line, 'message': message};
  