Constant wasmtime_environ::FUNCREF_MASK

pub const FUNCREF_MASK: usize = !FUNCREF_INIT_BIT; // 18_446_744_073_709_551_614usize

The mask we apply to all refs loaded from funcref tables.

This allows us to use the LSB as an “initialized flag” (see below) to distinguish from an uninitialized element in a lazily-initialized funcref table.