Function codegen_program_mapped 

pub fn codegen_program_mapped(
    stmts: &[Stmt<'_>],
    registry: &TypeRegistry,
    policies: &PolicyRegistry,
    interner: &Interner,
    type_env: &TypeEnv,
    cfg: &OptimizationConfig,
    stmt_spans: &[Span],
    logos_source: &str,
) -> (String, SourceMap)

Like codegen_program, but also builds the rustc→LOGOS SourceMap: every generated line maps to the top-level statement that produced it (stmt_spans is the parser’s side-table, 1:1 with stmts; zero-width spans mark prelude statements and are skipped), and variable origins carry ownership roles for the diagnostic bridge. This is the flycheck substrate.