---
source: crates/biome_js_analyze/tests/spec_tests.rs
expression: invalid.jsonc
---
# Input
```cjs
var a = 3; var a = 10;
```

# Diagnostics
```
invalid.jsonc:1:16 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ var a = 3; var a = 10;
      │                ^
  
  i 'a' is defined here:
  
  > 1 │ var a = 3; var a = 10;
      │     ^
  

```

# Input
```cjs
var c; { var a; var a;} 
```

# Diagnostics
```
invalid.jsonc:1:21 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ var c; { var a; var a;}·
      │                     ^
  
  i 'a' is defined here:
  
  > 1 │ var c; { var a; var a;}·
      │              ^
  

```

# Input
```cjs
var a; { function a(){} }
```

# Diagnostics
```
invalid.jsonc:1:19 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ var a; { function a(){} }
      │                   ^
  
  i 'a' is defined here:
  
  > 1 │ var a; { function a(){} }
      │     ^
  

```

# Input
```cjs
switch(foo) { case a: var b = 3;
case b: var b = 4}
```

# Diagnostics
```
invalid.jsonc:2:13 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'b'. Consider to delete it or rename it.
  
    1 │ switch(foo) { case a: var b = 3;
  > 2 │ case b: var b = 4}
      │             ^
  
  i 'b' is defined here:
  
  > 1 │ switch(foo) { case a: var b = 3;
      │                           ^
    2 │ case b: var b = 4}
  

```

# Input
```cjs
var a = 3; var a = 10;
```

# Diagnostics
```
invalid.jsonc:1:16 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ var a = 3; var a = 10;
      │                ^
  
  i 'a' is defined here:
  
  > 1 │ var a = 3; var a = 10;
      │     ^
  

```

# Input
```cjs
var a = {}; var a = [];
```

# Diagnostics
```
invalid.jsonc:1:17 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ var a = {}; var a = [];
      │                 ^
  
  i 'a' is defined here:
  
  > 1 │ var a = {}; var a = [];
      │     ^
  

```

# Input
```cjs
var a; function a() {}
```

# Diagnostics
```
invalid.jsonc:1:17 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ var a; function a() {}
      │                 ^
  
  i 'a' is defined here:
  
  > 1 │ var a; function a() {}
      │     ^
  

```

# Input
```cjs
function a() {} function a() {}
```

# Diagnostics
```
invalid.jsonc:1:26 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ function a() {} function a() {}
      │                          ^
  
  i 'a' is defined here:
  
  > 1 │ function a() {} function a() {}
      │          ^
  

```

# Input
```cjs
var a = function() { }; var a = function() { }
```

# Diagnostics
```
invalid.jsonc:1:29 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ var a = function() { }; var a = function() { }
      │                             ^
  
  i 'a' is defined here:
  
  > 1 │ var a = function() { }; var a = function() { }
      │     ^
  

```

# Input
```cjs
var a = function() { }; var a = new Date();
```

# Diagnostics
```
invalid.jsonc:1:29 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ var a = function() { }; var a = new Date();
      │                             ^
  
  i 'a' is defined here:
  
  > 1 │ var a = function() { }; var a = new Date();
      │     ^
  

```

# Input
```cjs
var a = 3; var a = 10; var a = 15;
```

# Diagnostics
```
invalid.jsonc:1:16 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ var a = 3; var a = 10; var a = 15;
      │                ^
  
  i 'a' is defined here:
  
  > 1 │ var a = 3; var a = 10; var a = 15;
      │     ^
  

```

```
invalid.jsonc:1:28 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ var a = 3; var a = 10; var a = 15;
      │                            ^
  
  i 'a' is defined here:
  
  > 1 │ var a = 3; var a = 10; var a = 15;
      │     ^
  

```

# Input
```cjs
var a; var a;
```

# Diagnostics
```
invalid.jsonc:1:12 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ var a; var a;
      │            ^
  
  i 'a' is defined here:
  
  > 1 │ var a; var a;
      │     ^
  

```

# Input
```cjs
export var a; var a;
```

# Diagnostics
```
invalid.jsonc:1:19 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ export var a; var a;
      │                   ^
  
  i 'a' is defined here:
  
  > 1 │ export var a; var a;
      │            ^
  

```

# Input
```cjs
class C { static { var a; var a; } }
```

# Diagnostics
```
invalid.jsonc:1:31 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ class C { static { var a; var a; } }
      │                               ^
  
  i 'a' is defined here:
  
  > 1 │ class C { static { var a; var a; } }
      │                        ^
  

```

# Input
```cjs
class C { static { var a; { var a; } } }
```

# Diagnostics
```
invalid.jsonc:1:33 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ class C { static { var a; { var a; } } }
      │                                 ^
  
  i 'a' is defined here:
  
  > 1 │ class C { static { var a; { var a; } } }
      │                        ^
  

```

# Input
```cjs
class C { static { { var a; } var a; } }
```

# Diagnostics
```
invalid.jsonc:1:35 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ class C { static { { var a; } var a; } }
      │                                   ^
  
  i 'a' is defined here:
  
  > 1 │ class C { static { { var a; } var a; } }
      │                          ^
  

```

# Input
```cjs
class C { static { { var a; } { var a; } } }
```

# Diagnostics
```
invalid.jsonc:1:37 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ class C { static { { var a; } { var a; } } }
      │                                     ^
  
  i 'a' is defined here:
  
  > 1 │ class C { static { { var a; } { var a; } } }
      │                          ^
  

```

# Input
```cjs
var a; var {a = 0, b: Object = 0} = {};
```

# Diagnostics
```
invalid.jsonc:1:13 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ var a; var {a = 0, b: Object = 0} = {};
      │             ^
  
  i 'a' is defined here:
  
  > 1 │ var a; var {a = 0, b: Object = 0} = {};
      │     ^
  

```

# Input
```cjs
var a; var {a = 0, b: globalThis = 0} = {};
```

# Diagnostics
```
invalid.jsonc:1:13 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ var a; var {a = 0, b: globalThis = 0} = {};
      │             ^
  
  i 'a' is defined here:
  
  > 1 │ var a; var {a = 0, b: globalThis = 0} = {};
      │     ^
  

```

# Input
```cjs
function f() { var a; var a; }
```

# Diagnostics
```
invalid.jsonc:1:27 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ function f() { var a; var a; }
      │                           ^
  
  i 'a' is defined here:
  
  > 1 │ function f() { var a; var a; }
      │                    ^
  

```

# Input
```cjs
function f() { var a; if (test) { var a; } }
```

# Diagnostics
```
invalid.jsonc:1:39 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ function f() { var a; if (test) { var a; } }
      │                                       ^
  
  i 'a' is defined here:
  
  > 1 │ function f() { var a; if (test) { var a; } }
      │                    ^
  

```

# Input
```cjs
for (var a, a;;);
```

# Diagnostics
```
invalid.jsonc:1:13 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ for (var a, a;;);
      │             ^
  
  i 'a' is defined here:
  
  > 1 │ for (var a, a;;);
      │          ^
  

```

# Input
```cjs
for (;;){ var a, a,;}
```

# Diagnostics
```
invalid.jsonc:1:18 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Shouldn't redeclare 'a'. Consider to delete it or rename it.
  
  > 1 │ for (;;){ var a, a,;}
      │                  ^
  
  i 'a' is defined here:
  
  > 1 │ for (;;){ var a, a,;}
      │               ^
  

```

# Input
```cjs
function f(x) { var x = 5; }
```