---
source: crates/biome_js_analyze/tests/spec_tests.rs
expression: invalid.ts
---
# Input
```ts
class C {
    constructor(readonly a = b, readonly b = 0) {}
}

```

# Diagnostics
```
invalid.ts:2:30 lint/correctness/noInvalidUseBeforeDeclaration ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! This parameter is used before its declaration.
  
    1 │ class C {
  > 2 │     constructor(readonly a = b, readonly b = 0) {}
      │                              ^
    3 │ }
    4 │ 
  
  i The parameter is declared here:
  
    1 │ class C {
  > 2 │     constructor(readonly a = b, readonly b = 0) {}
      │                                          ^
    3 │ }
    4 │ 
  

```