anchor.diff:      });
     }
   
  +  String formatErrorMessage(
  +      AnalysisError error, String filename, LineInfo lines) {
  +    var location = lines.getLocation(error.offset);
  +    return '[error] ${error.message} ($filename, '
  +        'line ${location.lineNumber}, '
  +        'col ${location.columnNumber})';
  +  }
  +
     void ensureLibraryIsLoaded(ast.Library node) {
       if (node.isLoaded) return;
       var source = context.sourceFactory.forUri2(node.importUri);
  
positive.code:     context.resolveCompilationUnit(source, element);
      _buildLibraryBody(element, node);
      for (var unit in element.units) {
        for (var error in context.computeErrors(unit.source)) {
          if (error.errorCode is CompileTimeErrorCode ||
              error.errorCode is ParserErrorCode ||
  
negative.code:             // Ignore warnings about 'const' factories in the patched SDK.
              continue;
            }
            lines ??= context.computeLineInfo(source);
            errors.add(formatErrorMessage(error, source.shortName, lines));
          }
        }
      }
  