Function lower_functions 

pub fn lower_functions<I, Ty, C>(
    functions: Vec<ParsedFunction<I, Ty>>,
    context: &mut C,
) -> Result<Vec<I::Runtime>>
where
    I: Lower<C>,
    C: FunctionScope,

Lower functions in source order, preparing each function’s complete label scope before lowering its first instruction.

Each syntax instruction lowers to one runtime instruction. Errors include function and instruction context; no partial code vector is returned. Context mutations before an error are not rolled back.