Don’t overwrite a file with a directory

Sources/Path+FileManager.swift

@@ -5,13 +5,14 @@ public extension Path {
      Copies a file.
      - Note: `throws` if `to` is a directory.
      - Parameter to: Destination filename.
-     - Parameter overwrite: If true overwrites any file that already exists at `to`.
+     - Parameter overwrite: If `true` and both `self` and `to` are files, overwrites `to`.
+     - Note: If either `self` or `to are directories, `overwrite` is ignored.
      - Returns: `to` to allow chaining
      - SeeAlso: `copy(into:overwrite:)`
      */
     @discardableResult
     public func copy(to: Path, overwrite: Bool = false) throws -> Path {
-        if overwrite, to.exists {
+        if overwrite, to.isFile, isFile {
             try FileManager.default.removeItem(at: to.url)
         }
         try FileManager.default.copyItem(atPath: string, toPath: to.string)