# XO0601: name does not resolve

A variable, function, type, field, method, module, or effect name does not exist where it is used. The diagnostic suggests the nearest real names, so an API cannot be hallucinated silently. It also covers `os`, `expect`, and `testing` outside tests, a tuple field out of range, and `result` outside an `ensures` clause. `Float.from(n)` and other unknown associated functions of a numeric type called with one numeric argument get the fix `Float(n)`: numeric conversions are calls on the type name (std.md 2.1). See core 4.3.

## Example

```xo
fn f() -> Int {
  let count = 1
  coutn
}
```

## Fix

```xo
fn f() -> Int {
  let count = 1
  count
}
```

Run `xo explain XO0601` for this text in a terminal, or see
[section 10.6 of the specification](../../spec/core/#106-diagnostic-codes).