void visitConstructorDeclaration()

in lib/src/rules/prefer_initializing_formals.dart [137:213]
66 lines of code
21 McCabe index (conditional complexity)

  void visitConstructorDeclaration(ConstructorDeclaration node) {
    // Skip factory constructors.
    // https://github.com/dart-lang/linter/issues/2441
    if (node.factoryKeyword != null) {
      return;
    }

    var parameters = _getParameters(node);
    var parametersUsedOnce = <Element?>{};
    var parametersUsedMoreThanOnce = <Element?>{};

    bool isAssignmentExpressionToLint(AssignmentExpression assignment) {
      var leftElement = _getLeftElement(assignment);
      var rightElement = _getRightElement(assignment);
      return leftElement != null &&
          rightElement != null &&
          leftElement.name == rightElement.name &&
          !leftElement.isPrivate &&
          leftElement is FieldElement &&
          !leftElement.isSynthetic &&
          leftElement.enclosingElement ==
              node.declaredElement?.enclosingElement &&
          parameters.contains(rightElement) &&
          (!parametersUsedMoreThanOnce.contains(rightElement) &&
                  !(rightElement as ParameterElement).isNamed ||
              leftElement.name == rightElement.name);
    }

    bool isConstructorFieldInitializerToLint(
        ConstructorFieldInitializer constructorFieldInitializer) {
      var expression = constructorFieldInitializer.expression;
      if (expression is SimpleIdentifier) {
        var fieldName = constructorFieldInitializer.fieldName;
        if (fieldName.name != expression.name) {
          return false;
        }
        var staticElement = expression.staticElement;
        return staticElement is ParameterElement &&
            !(constructorFieldInitializer.fieldName.staticElement?.isPrivate ??
                true) &&
            parameters.contains(staticElement) &&
            (!parametersUsedMoreThanOnce.contains(expression.staticElement) &&
                    !staticElement.isNamed ||
                (constructorFieldInitializer.fieldName.staticElement?.name ==
                    expression.staticElement?.name));
      }
      return false;
    }

    void processElement(Element? element) {
      if (!parametersUsedOnce.add(element)) {
        parametersUsedMoreThanOnce.add(element);
      }
    }

    node.parameters.parameterElements
        .where((p) => p != null && p.isInitializingFormal)
        .forEach(processElement);

    _getAssignmentExpressionsInConstructorBody(node)
        .where(isAssignmentExpressionToLint)
        .map(_getRightElement)
        .forEach(processElement);

    _getConstructorFieldInitializersInInitializers(node)
        .where(isConstructorFieldInitializerToLint)
        .map((e) => (e.expression as SimpleIdentifier).staticElement)
        .forEach(processElement);

    _getAssignmentExpressionsInConstructorBody(node)
        .where(isAssignmentExpressionToLint)
        .forEach(rule.reportLint);

    _getConstructorFieldInitializersInInitializers(node)
        .where(isConstructorFieldInitializerToLint)
        .forEach(rule.reportLint);
  }