---
source: crates/biome_js_analyze/tests/spec_tests.rs
expression: invalid.js
---
# Input
```jsx
function* foo() {
	return 0;
}

(function* foo() {
	return 0;
})();

const obj = {
	*foo() {
		return 0;
	},
};

class A {
	*foo() {
		return 0;
	}
}

function* foo() {
	function* bar() {
		yield 0;
	}
}

function* foo() {
	function* bar() {
		return 0;
	}
	yield 0;
}

function* foo() {
	function* bar() {
		yield 0;
	}
	return 0;
}

function* foo() {
	const obj = {
		*bar() {
			return 0;
		},
	};

	class A {
		*baz() {
			return 0;
		}
	}

	if (a === 'a') {
		yield 0;
	}
}

```

# Diagnostics
```
invalid.js:1:1 lint/correctness/useYield ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This generator function doesn't contain yield.
  
  > 1 │ function* foo() {
      │ ^^^^^^^^^^^^^^^^^
  > 2 │ 	return 0;
  > 3 │ }
      │ ^
    4 │ 
    5 │ (function* foo() {
  

```

```
invalid.js:5:2 lint/correctness/useYield ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This generator function doesn't contain yield.
  
    3 │ }
    4 │ 
  > 5 │ (function* foo() {
      │  ^^^^^^^^^^^^^^^^^
  > 6 │ 	return 0;
  > 7 │ })();
      │ ^
    8 │ 
    9 │ const obj = {
  

```

```
invalid.js:10:2 lint/correctness/useYield ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This generator function doesn't contain yield.
  
     9 │ const obj = {
  > 10 │ 	*foo() {
       │ 	^^^^^^^^
  > 11 │ 		return 0;
  > 12 │ 	},
       │ 	^
    13 │ };
    14 │ 
  

```

```
invalid.js:16:2 lint/correctness/useYield ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This generator function doesn't contain yield.
  
    15 │ class A {
  > 16 │ 	*foo() {
       │ 	^^^^^^^^
  > 17 │ 		return 0;
  > 18 │ 	}
       │ 	^
    19 │ }
    20 │ 
  

```

```
invalid.js:21:1 lint/correctness/useYield ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This generator function doesn't contain yield.
  
    19 │ }
    20 │ 
  > 21 │ function* foo() {
       │ ^^^^^^^^^^^^^^^^^
  > 22 │ 	function* bar() {
  > 23 │ 		yield 0;
  > 24 │ 	}
  > 25 │ }
       │ ^
    26 │ 
    27 │ function* foo() {
  

```

```
invalid.js:28:2 lint/correctness/useYield ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This generator function doesn't contain yield.
  
    27 │ function* foo() {
  > 28 │ 	function* bar() {
       │ 	^^^^^^^^^^^^^^^^^
  > 29 │ 		return 0;
  > 30 │ 	}
       │ 	^
    31 │ 	yield 0;
    32 │ }
  

```

```
invalid.js:34:1 lint/correctness/useYield ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This generator function doesn't contain yield.
  
    32 │ }
    33 │ 
  > 34 │ function* foo() {
       │ ^^^^^^^^^^^^^^^^^
  > 35 │ 	function* bar() {
  > 36 │ 		yield 0;
  > 37 │ 	}
  > 38 │ 	return 0;
  > 39 │ }
       │ ^
    40 │ 
    41 │ function* foo() {
  

```

```
invalid.js:43:3 lint/correctness/useYield ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This generator function doesn't contain yield.
  
    41 │ function* foo() {
    42 │ 	const obj = {
  > 43 │ 		*bar() {
       │ 		^^^^^^^^
  > 44 │ 			return 0;
  > 45 │ 		},
       │ 		^
    46 │ 	};
    47 │ 
  

```

```
invalid.js:49:3 lint/correctness/useYield ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This generator function doesn't contain yield.
  
    48 │ 	class A {
  > 49 │ 		*baz() {
       │ 		^^^^^^^^
  > 50 │ 			return 0;
  > 51 │ 		}
       │ 		^
    52 │ 	}
    53 │ 
  

```