---
source: crates/biome_js_analyze/tests/spec_tests.rs
expression: noUndeclaredVariables.ts
---
# Input
```ts
export type Invalid<S extends number> = `Hello ${T}`

export type Invalid<S extends number> = `
    Hello
    ${T}
`
```

# Diagnostics
```
noUndeclaredVariables.ts:1:50 lint/correctness/noUndeclaredVariables  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━

  ! The T variable is undeclared
  
  > 1 │ export type Invalid<S extends number> = `Hello ${T}`
      │                                                  ^
    2 │ 
    3 │ export type Invalid<S extends number> = `
  
  i Safe fix: Suppress rule lint/correctness/noUndeclaredVariables
  
    1   │ - export·type·Invalid<S·extends·number>·=·`Hello·${T}`
      1 │ + export·type·Invalid<S·extends·number>·=·`Hello·${//·biome-ignore·lint/correctness/noUndeclaredVariables:·<explanation>
      2 │ + T}`
    2 3 │   
    3 4 │   export type Invalid<S extends number> = `
  

```

```
noUndeclaredVariables.ts:5:7 lint/correctness/noUndeclaredVariables  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━

  ! The T variable is undeclared
  
    3 │ export type Invalid<S extends number> = `
    4 │     Hello
  > 5 │     ${T}
      │       ^
    6 │ `
  
  i Safe fix: Suppress rule lint/correctness/noUndeclaredVariables
  
    3 3 │   export type Invalid<S extends number> = `
    4 4 │       Hello
    5   │ - ····${T}
      5 │ + ····${//·biome-ignore·lint/correctness/noUndeclaredVariables:·<explanation>
      6 │ + T}
    6 7 │   `
  

```