Ref7 method

P Ref7([
  1. X? o
])

Allocates o into slot '7', or reuses the existing slot '7' allocation if o is null.

Intended as a short-lived scratch reference within a single C call. Use RefUpdate7 if the callee may write back into the pointer.

Implementation

P Ref7([X? o]) => _Ref(o, '7');