---
source: crates/biome_js_analyze/tests/spec_tests.rs
expression: invalid.js
---
# Input
```jsx
a;
const a = 0;

const b = b;

c;
let c;

let d = d;

e;
var e;

var f = f;

function f(a = b, b = 0) {}

function g(a = a) {}

```

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

  ! This variable is used before its declaration.
  
  > 1 │ a;
      │ ^
    2 │ const a = 0;
    3 │ 
  
  i The variable is declared here:
  
    1 │ a;
  > 2 │ const a = 0;
      │       ^
    3 │ 
    4 │ const b = b;
  

```

```
invalid.js:4:11 lint/correctness/noInvalidUseBeforeDeclaration ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This variable is used before its declaration.
  
    2 │ const a = 0;
    3 │ 
  > 4 │ const b = b;
      │           ^
    5 │ 
    6 │ c;
  
  i The variable is declared here:
  
    2 │ const a = 0;
    3 │ 
  > 4 │ const b = b;
      │       ^
    5 │ 
    6 │ c;
  

```

```
invalid.js:4:13 lint/correctness/noInvalidUseBeforeDeclaration ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This variable is used before its declaration.
  
    2 │ const a = 0;
    3 │ 
  > 4 │ const b = b;
      │             
  > 5 │ 
  > 6 │ c;
      │ ^
    7 │ let c;
    8 │ 
  
  i The variable is declared here:
  
    6 │ c;
  > 7 │ let c;
      │     ^
    8 │ 
    9 │ let d = d;
  

```

```
invalid.js:9:9 lint/correctness/noInvalidUseBeforeDeclaration ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This variable is used before its declaration.
  
     7 │ let c;
     8 │ 
   > 9 │ let d = d;
       │         ^
    10 │ 
    11 │ e;
  
  i The variable is declared here:
  
     7 │ let c;
     8 │ 
   > 9 │ let d = d;
       │     ^
    10 │ 
    11 │ e;
  

```

```
invalid.js:9:11 lint/correctness/noInvalidUseBeforeDeclaration ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This variable is used before its declaration.
  
     7 │ let c;
     8 │ 
   > 9 │ let d = d;
       │           
  > 10 │ 
  > 11 │ e;
       │ ^
    12 │ var e;
    13 │ 
  
  i The variable is declared here:
  
    11 │ e;
  > 12 │ var e;
       │     ^
    13 │ 
    14 │ var f = f;
  

```

```
invalid.js:16:16 lint/correctness/noInvalidUseBeforeDeclaration ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This parameter is used before its declaration.
  
    14 │ var f = f;
    15 │ 
  > 16 │ function f(a = b, b = 0) {}
       │                ^
    17 │ 
    18 │ function g(a = a) {}
  
  i The parameter is declared here:
  
    14 │ var f = f;
    15 │ 
  > 16 │ function f(a = b, b = 0) {}
       │                   ^
    17 │ 
    18 │ function g(a = a) {}
  

```

```
invalid.js:18:16 lint/correctness/noInvalidUseBeforeDeclaration ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This parameter is used before its declaration.
  
    16 │ function f(a = b, b = 0) {}
    17 │ 
  > 18 │ function g(a = a) {}
       │                ^
    19 │ 
  
  i The parameter is declared here:
  
    16 │ function f(a = b, b = 0) {}
    17 │ 
  > 18 │ function g(a = a) {}
       │            ^
    19 │ 
  

```