Method ensure_index_at

winch/codegen/src/stack.rs:332–338

Ensures that there are at least `n` elements in the value stack, and returns the index calculated by: stack length minus `n`.

(&self, n: usize)

    /// Ensures that there are at least `n` elements in the value stack,
    /// and returns the index calculated by: stack length minus `n`.
    pub fn ensure_index_at(&self, n: usize) -> Result<usize> {
        if self.len() >= n {
            Ok(self.len() - n)
        } else {
            Err(format_err!(CodeGenError::missing_values_in_stack()))
        }
    }

    /// Returns true if the stack contains a local with the provided index
    /// except if the only time the local appears is the top element.