# Problem
Before this PR, our formatter reformats
```
squares_out = reduce(arr, 0, fn (i, squares) {
return 1
})
```
to
```
squares_out = reduce(arr, 0, (i, squares) {
return 1
})
```
i.e. it removes the `fn` keyword from the closure. This keyword is required, so, our formatter turned working code into invalid code.
# Cause
When this closure parameter is formatted, the ExprContext is ::Decl, so `Expr::recast` skips adding the `fn` keyword. The reason it's ::Decl is because the `squares_out = ` declaration sets it, and no subsequent call sets the context to something else.
# Solution
When recasting a call expression, set the context for every argument to `ExprContext::Other`.
6aa588f09f