Function clone_stack_value 

pub unsafe fn clone_stack_value(sv: &StackValue) -> StackValue

Clone a StackValue, handling reference counting for heap types.

Cloning Strategy by Type

• Int, Float, Bool, Quotation: Bitwise copy (no heap allocation)
• String: Deep copy to a new global (refcounted) string. This is necessary because the source may be an arena-allocated string that would become invalid when the arena resets. Global strings are heap-allocated with Arc refcounting.
• Variant: Arc refcount increment (O(1), shares underlying data)
• Map: Deep clone of the HashMap and all contained values
• Closure: Deep clone of the Arc<Value> environment
• Channel: Arc refcount increment (O(1), shares underlying sender/receiver)

Safety

The StackValue must contain valid data for its discriminant.