---
source: crates/biome_js_analyze/tests/spec_tests.rs
expression: invalid.jsonc
---
# Input
```cjs
const a = s.toUpperCase() === 'abc';
```

# Diagnostics
```
invalid.jsonc:1:11 lint/correctness/noStringCaseMismatch  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This expression always returns false.
  
  > 1 │ const a = s.toUpperCase() === 'abc';
      │           ^^^^^^^^^^^^^^^^^^^^^^^^^
  
  i This call convert the string to upper case
  
  > 1 │ const a = s.toUpperCase() === 'abc';
      │           ^^^^^^^^^^^^^^^
  
  i ... but this value is not in upper case
  
  > 1 │ const a = s.toUpperCase() === 'abc';
      │                               ^^^^^
  
  i Unsafe fix: Use upper case string value.
  
  - const·a·=·s.toUpperCase()·===·'abc';
  + const·a·=·s.toUpperCase()·===·"ABC";
  

```

# Input
```cjs
const c = s.toUpperCase() == 'abc';
```

# Diagnostics
```
invalid.jsonc:1:11 lint/correctness/noStringCaseMismatch  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This expression always returns false.
  
  > 1 │ const c = s.toUpperCase() == 'abc';
      │           ^^^^^^^^^^^^^^^^^^^^^^^^
  
  i This call convert the string to upper case
  
  > 1 │ const c = s.toUpperCase() == 'abc';
      │           ^^^^^^^^^^^^^^^
  
  i ... but this value is not in upper case
  
  > 1 │ const c = s.toUpperCase() == 'abc';
      │                              ^^^^^
  
  i Unsafe fix: Use upper case string value.
  
  - const·c·=·s.toUpperCase()·==·'abc';
  + const·c·=·s.toUpperCase()·==·"ABC";
  

```

# Input
```cjs
const a2 = 'abc' === s.toUpperCase();
```

# Diagnostics
```
invalid.jsonc:1:12 lint/correctness/noStringCaseMismatch  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This expression always returns false.
  
  > 1 │ const a2 = 'abc' === s.toUpperCase();
      │            ^^^^^^^^^^^^^^^^^^^^^^^^^
  
  i This call convert the string to upper case
  
  > 1 │ const a2 = 'abc' === s.toUpperCase();
      │                      ^^^^^^^^^^^^^^^
  
  i ... but this value is not in upper case
  
  > 1 │ const a2 = 'abc' === s.toUpperCase();
      │            ^^^^^
  
  i Unsafe fix: Use upper case string value.
  
  - const·a2·=·'abc'·===·s.toUpperCase();
  + const·a2·=·"ABC"·===·s.toUpperCase();
  

```

# Input
```cjs
if (s.toUpperCase() === 'abc' && c == d && e == f) {}
```

# Diagnostics
```
invalid.jsonc:1:5 lint/correctness/noStringCaseMismatch  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This expression always returns false.
  
  > 1 │ if (s.toUpperCase() === 'abc' && c == d && e == f) {}
      │     ^^^^^^^^^^^^^^^^^^^^^^^^^
  
  i This call convert the string to upper case
  
  > 1 │ if (s.toUpperCase() === 'abc' && c == d && e == f) {}
      │     ^^^^^^^^^^^^^^^
  
  i ... but this value is not in upper case
  
  > 1 │ if (s.toUpperCase() === 'abc' && c == d && e == f) {}
      │                         ^^^^^
  
  i Unsafe fix: Use upper case string value.
  
  - if·(s.toUpperCase()·===·'abc'·&&·c·==·d·&&·e·==·f)·{}
  + if·(s.toUpperCase()·===·"ABC"·&&·c·==·d·&&·e·==·f)·{}
  

```

# Input
```cjs
while (s.toUpperCase() === 'abc' && c == d && e == f) {}
```

# Diagnostics
```
invalid.jsonc:1:8 lint/correctness/noStringCaseMismatch  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This expression always returns false.
  
  > 1 │ while (s.toUpperCase() === 'abc' && c == d && e == f) {}
      │        ^^^^^^^^^^^^^^^^^^^^^^^^^
  
  i This call convert the string to upper case
  
  > 1 │ while (s.toUpperCase() === 'abc' && c == d && e == f) {}
      │        ^^^^^^^^^^^^^^^
  
  i ... but this value is not in upper case
  
  > 1 │ while (s.toUpperCase() === 'abc' && c == d && e == f) {}
      │                            ^^^^^
  
  i Unsafe fix: Use upper case string value.
  
  - while·(s.toUpperCase()·===·'abc'·&&·c·==·d·&&·e·==·f)·{}
  + while·(s.toUpperCase()·===·"ABC"·&&·c·==·d·&&·e·==·f)·{}
  

```

# Input
```cjs
while (s.toUpperCase() === 'abc') {}
```

# Diagnostics
```
invalid.jsonc:1:8 lint/correctness/noStringCaseMismatch  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This expression always returns false.
  
  > 1 │ while (s.toUpperCase() === 'abc') {}
      │        ^^^^^^^^^^^^^^^^^^^^^^^^^
  
  i This call convert the string to upper case
  
  > 1 │ while (s.toUpperCase() === 'abc') {}
      │        ^^^^^^^^^^^^^^^
  
  i ... but this value is not in upper case
  
  > 1 │ while (s.toUpperCase() === 'abc') {}
      │                            ^^^^^
  
  i Unsafe fix: Use upper case string value.
  
  - while·(s.toUpperCase()·===·'abc')·{}
  + while·(s.toUpperCase()·===·"ABC")·{}
  

```

# Input
```cjs
let b = s.toLowerCase() === `eFg`;
```

# Diagnostics
```
invalid.jsonc:1:9 lint/correctness/noStringCaseMismatch  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This expression always returns false.
  
  > 1 │ let b = s.toLowerCase() === `eFg`;
      │         ^^^^^^^^^^^^^^^^^^^^^^^^^
  
  i This call convert the string to lower case
  
  > 1 │ let b = s.toLowerCase() === `eFg`;
      │         ^^^^^^^^^^^^^^^
  
  i ... but this value is not in lower case
  
  > 1 │ let b = s.toLowerCase() === `eFg`;
      │                             ^^^^^
  
  i Unsafe fix: Use lower case string value.
  
  - let·b·=·s.toLowerCase()·===·`eFg`;
  + let·b·=·s.toLowerCase()·===·"efg";
  

```

# Input
```cjs
do {} while (s.toLowerCase() === 'ABC');
```

# Diagnostics
```
invalid.jsonc:1:14 lint/correctness/noStringCaseMismatch  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This expression always returns false.
  
  > 1 │ do {} while (s.toLowerCase() === 'ABC');
      │              ^^^^^^^^^^^^^^^^^^^^^^^^^
  
  i This call convert the string to lower case
  
  > 1 │ do {} while (s.toLowerCase() === 'ABC');
      │              ^^^^^^^^^^^^^^^
  
  i ... but this value is not in lower case
  
  > 1 │ do {} while (s.toLowerCase() === 'ABC');
      │                                  ^^^^^
  
  i Unsafe fix: Use lower case string value.
  
  - do·{}·while·(s.toLowerCase()·===·'ABC');
  + do·{}·while·(s.toLowerCase()·===·"abc");
  

```

# Input
```cjs
for (; s.toLowerCase() === 'ABC'; ) {}
```

# Diagnostics
```
invalid.jsonc:1:8 lint/correctness/noStringCaseMismatch  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This expression always returns false.
  
  > 1 │ for (; s.toLowerCase() === 'ABC'; ) {}
      │        ^^^^^^^^^^^^^^^^^^^^^^^^^
  
  i This call convert the string to lower case
  
  > 1 │ for (; s.toLowerCase() === 'ABC'; ) {}
      │        ^^^^^^^^^^^^^^^
  
  i ... but this value is not in lower case
  
  > 1 │ for (; s.toLowerCase() === 'ABC'; ) {}
      │                            ^^^^^
  
  i Unsafe fix: Use lower case string value.
  
  - for·(;·s.toLowerCase()·===·'ABC';·)·{}
  + for·(;·s.toLowerCase()·===·"abc";·)·{}
  

```

# Input
```cjs
switch (s.toUpperCase()) { case 'ABC': case 'abc': case 'aBc': default: }
```

# Diagnostics
```
invalid.jsonc:1:45 lint/correctness/noStringCaseMismatch  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This case will never match.
  
  > 1 │ switch (s.toUpperCase()) { case 'ABC': case 'abc': case 'aBc': default: }
      │                                             ^^^^^
  
  i This call convert the string to upper case
  
  > 1 │ switch (s.toUpperCase()) { case 'ABC': case 'abc': case 'aBc': default: }
      │         ^^^^^^^^^^^^^^^
  
  i ... but this value is not in upper case
  
  > 1 │ switch (s.toUpperCase()) { case 'ABC': case 'abc': case 'aBc': default: }
      │                                             ^^^^^
  
  i Unsafe fix: Use upper case string value.
  
  - switch·(s.toUpperCase())·{·case·'ABC':·case·'abc':·case·'aBc':·default:·}
  + switch·(s.toUpperCase())·{·case·'ABC':·case·"ABC":·case·'aBc':·default:·}
  

```

```
invalid.jsonc:1:57 lint/correctness/noStringCaseMismatch  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This case will never match.
  
  > 1 │ switch (s.toUpperCase()) { case 'ABC': case 'abc': case 'aBc': default: }
      │                                                         ^^^^^
  
  i This call convert the string to upper case
  
  > 1 │ switch (s.toUpperCase()) { case 'ABC': case 'abc': case 'aBc': default: }
      │         ^^^^^^^^^^^^^^^
  
  i ... but this value is not in upper case
  
  > 1 │ switch (s.toUpperCase()) { case 'ABC': case 'abc': case 'aBc': default: }
      │                                                         ^^^^^
  
  i Unsafe fix: Use upper case string value.
  
  - switch·(s.toUpperCase())·{·case·'ABC':·case·'abc':·case·'aBc':·default:·}
  + switch·(s.toUpperCase())·{·case·'ABC':·case·'abc':·case·"ABC":·default:·}
  

```

# Input
```cjs
for (; s['toLowerCase']() === 'ABC'; ) {}
```

# Diagnostics
```
invalid.jsonc:1:8 lint/correctness/noStringCaseMismatch  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This expression always returns false.
  
  > 1 │ for (; s['toLowerCase']() === 'ABC'; ) {}
      │        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  
  i This call convert the string to lower case
  
  > 1 │ for (; s['toLowerCase']() === 'ABC'; ) {}
      │        ^^^^^^^^^^^^^^^^^^
  
  i ... but this value is not in lower case
  
  > 1 │ for (; s['toLowerCase']() === 'ABC'; ) {}
      │                               ^^^^^
  
  i Unsafe fix: Use lower case string value.
  
  - for·(;·s['toLowerCase']()·===·'ABC';·)·{}
  + for·(;·s['toLowerCase']()·===·"abc";·)·{}
  

```

# Input
```cjs
for (; s[`toUpperCase`]() === 'abc'; ) {}
```

# Diagnostics
```
invalid.jsonc:1:8 lint/correctness/noStringCaseMismatch  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This expression always returns false.
  
  > 1 │ for (; s[`toUpperCase`]() === 'abc'; ) {}
      │        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  
  i This call convert the string to upper case
  
  > 1 │ for (; s[`toUpperCase`]() === 'abc'; ) {}
      │        ^^^^^^^^^^^^^^^^^^
  
  i ... but this value is not in upper case
  
  > 1 │ for (; s[`toUpperCase`]() === 'abc'; ) {}
      │                               ^^^^^
  
  i Unsafe fix: Use upper case string value.
  
  - for·(;·s[`toUpperCase`]()·===·'abc';·)·{}
  + for·(;·s[`toUpperCase`]()·===·"ABC";·)·{}
  

```

# Input
```cjs
switch (s['toLowerCase']()) { case 'Abc': case 'aBc': case 'abC': default: }
```

# Diagnostics
```
invalid.jsonc:1:36 lint/correctness/noStringCaseMismatch  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This case will never match.
  
  > 1 │ switch (s['toLowerCase']()) { case 'Abc': case 'aBc': case 'abC': default: }
      │                                    ^^^^^
  
  i This call convert the string to lower case
  
  > 1 │ switch (s['toLowerCase']()) { case 'Abc': case 'aBc': case 'abC': default: }
      │         ^^^^^^^^^^^^^^^^^^
  
  i ... but this value is not in lower case
  
  > 1 │ switch (s['toLowerCase']()) { case 'Abc': case 'aBc': case 'abC': default: }
      │                                    ^^^^^
  
  i Unsafe fix: Use lower case string value.
  
  - switch·(s['toLowerCase']())·{·case·'Abc':·case·'aBc':·case·'abC':·default:·}
  + switch·(s['toLowerCase']())·{·case·"abc":·case·'aBc':·case·'abC':·default:·}
  

```

```
invalid.jsonc:1:48 lint/correctness/noStringCaseMismatch  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This case will never match.
  
  > 1 │ switch (s['toLowerCase']()) { case 'Abc': case 'aBc': case 'abC': default: }
      │                                                ^^^^^
  
  i This call convert the string to lower case
  
  > 1 │ switch (s['toLowerCase']()) { case 'Abc': case 'aBc': case 'abC': default: }
      │         ^^^^^^^^^^^^^^^^^^
  
  i ... but this value is not in lower case
  
  > 1 │ switch (s['toLowerCase']()) { case 'Abc': case 'aBc': case 'abC': default: }
      │                                                ^^^^^
  
  i Unsafe fix: Use lower case string value.
  
  - switch·(s['toLowerCase']())·{·case·'Abc':·case·'aBc':·case·'abC':·default:·}
  + switch·(s['toLowerCase']())·{·case·'Abc':·case·"abc":·case·'abC':·default:·}
  

```

```
invalid.jsonc:1:60 lint/correctness/noStringCaseMismatch  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This case will never match.
  
  > 1 │ switch (s['toLowerCase']()) { case 'Abc': case 'aBc': case 'abC': default: }
      │                                                            ^^^^^
  
  i This call convert the string to lower case
  
  > 1 │ switch (s['toLowerCase']()) { case 'Abc': case 'aBc': case 'abC': default: }
      │         ^^^^^^^^^^^^^^^^^^
  
  i ... but this value is not in lower case
  
  > 1 │ switch (s['toLowerCase']()) { case 'Abc': case 'aBc': case 'abC': default: }
      │                                                            ^^^^^
  
  i Unsafe fix: Use lower case string value.
  
  - switch·(s['toLowerCase']())·{·case·'Abc':·case·'aBc':·case·'abC':·default:·}
  + switch·(s['toLowerCase']())·{·case·'Abc':·case·'aBc':·case·"abc":·default:·}
  

```