Function walk_in_scope 

pub fn walk_in_scope<'a>(
    expression: &'a Expression,
    bfs: bool,
) -> impl Iterator<Item = &'a Expression>

Walk within a scope, yielding expressions without crossing scope boundaries.

This iterator visits all nodes in the syntax tree, stopping at nodes that start child scopes (CTEs, derived tables, subqueries in FROM/JOIN).

Arguments

• expression - The expression to walk
• bfs - If true, uses breadth-first search; otherwise uses depth-first search

Returns

An iterator over expressions within the scope