E0065

Warning name: prefer_readonly_array

Suggest ReadOnlyArray for read-only array literal.

This warning is emitted when the compiler can infer that an array literal is used in a read-only way. Consider using ReadOnlyArray to better express intent.

Erroneous example

test {
  let xs = [1, 2, 3]
  inspect(xs[0], content="1")
}

Suggestion

Annotate the array literal as ReadOnlyArray:

test {
  let xs : ReadOnlyArray[Int] = [1, 2, 3]
  inspect(xs[0], content="1")
}