Function render_errors_short 

pub fn render_errors_short(
    errors: &[CompileError],
    source: &str,
    filename: &str,
) -> String

The string form of print_errors_short — one …[category]: message line per error, each newline-terminated. The renderer behind the CLI’s --format short, exposed for testing.

Finding #47 doesn’t reach this one: tests/check_format_short.rs locks short to exactly one line per diagnostic (the VS Code problem-matcher’s contract), so notes/labels can’t grow extra lines here without breaking a real machine consumer — unlike print_project_errors/render_project_errors, which have no such one-line contract.