message: Mark readonly
diff: @@ -33,7 +33,7 @@ export class CppConfigurationProvider implements cpt.CustomConfigurationProvider
  dispose() {}
  - private _fileIndex = new Map<string, cpt.SourceFileConfigurationItem>();
  + private readonly _fileIndex = new Map<string, cpt.SourceFileConfigurationItem>();
  private _buildConfigurationData(grp: cms.CodeModelFileGroup, opts: CodeModelParams): cpt.SourceFileConfiguration {
  const lang = grp.language || 'CXX';
  