# `overlapping-fields-can-be-merged`

✅ The `"extends": "plugin:@graphql-eslint/operations-recommended"` property in a configuration file enables this rule.

- Category: `Operations`
- Rule name: `@graphql-eslint/overlapping-fields-can-be-merged`
- Requires GraphQL Schema: `true` [ℹ️](../../README.md#extended-linting-rules-with-graphql-schema)
- Requires GraphQL Operations: `false` [ℹ️](../../README.md#extended-linting-rules-with-siblings-operations)

A selection set is only valid if all fields (including spreading any fragments) either correspond to distinct response names or can be merged without ambiguity.

> This rule is a wrapper around a `graphql-js` validation function. [You can find its source code here](https://github.com/graphql/graphql-js/blob/main/src/validation/rules/OverlappingFieldsCanBeMergedRule.ts).

## Resources

- [Rule source](https://github.com/graphql/graphql-js/blob/main/src/validation/rules/OverlappingFieldsCanBeMergedRule.ts)
- [Test source](https://github.com/graphql/graphql-js/tree/main/src/validation/__tests__/OverlappingFieldsCanBeMergedRule-test.ts)