Function ordered_fn_components 

pub fn ordered_fn_components<'a>(
    fns: &[&'a FnDef],
    module_prefixes: &HashSet<String>,
) -> Vec<Vec<&'a FnDef>>

Deterministic function emission order for codegen backends.

Returns SCC components in callee-before-caller topological order. Each inner vector is one SCC (single function or mutual-recursive group). Function references passed as call arguments (e.g. apply(f, x)) are treated as dependencies for ordering.