Function walk_program 

pub fn walk_program<'arena, 'src, V: Visitor<'arena, 'src> + ?Sized>(
    visitor: &mut V,
    program: &Program<'arena, 'src>,
) -> ControlFlow<()>

Visits every top-level statement in program by calling Visitor::visit_stmt.

This is the entry point for a full-file traversal. Call it from Visitor::visit_program (which is the default) or drive it directly:

walk_program(v, program);