//! Bug regression: the workspace-monomorphisation pass must seed
//! `env.globals` for the current module before re-running `synth` on
//! a fn body, otherwise self-recursive top-level fns are rejected with
//! `unknown identifier` whenever the workspace also contains a
//! `Def::Class` (which makes the mono pass actually traverse bodies
//! instead of identity-cloning the workspace).
//!
//! Surfaced by the 2026-05-10 mono-vs-vdisp micro-benchmark: the
//! original bench fixture had a self-recursive `loop` fn alongside a
//! `Foo` class, and `ail build` failed at the mono pass with
//! `monomorphise_workspace: unknown identifier: \`loop\``. The bench
//! worked around it by also wrapping the loop in a class method,
//! masking but not fixing the defect.

use std::path::Path;
use std::process::Command;

fn ail_bin() -> &'static str {
    env!("CARGO_BIN_EXE_ail")
}

/// Property: a workspace that mixes a `Def::Class` / `Def::Instance`
/// with a self-recursive top-level `Def::Fn` (one whose body refers
/// to its own name) must build and run end-to-end. The mono pass
/// re-runs `synth` on every fn body to recover residual class
/// constraints; that env must agree with the env the main typecheck
/// path used, including `env.globals` for the current module.
///
/// Pre-fix: `ail build` fails at the mono pass with
/// `monomorphise_workspace: unknown identifier: \`loop\`` because
/// `mono::build_workspace_env` populates `env.module_globals` but
/// never seeds `env.globals` from the current module's fns —
/// `synth`'s `Term::Var` lookup at `lib.rs:1678` falls through to
/// the qualified-cross-module branch and finally to `UnknownIdent`.
/// The analogous gap for ADTs / ctors was fixed in commit 5c5180f
/// (iter 22c); this is the sibling gap for plain top-level fns.
#[test]
fn mono_pass_handles_recursive_fn_in_class_workspace() {
    let manifest_dir = env!("CARGO_MANIFEST_DIR");
    let workspace = Path::new(manifest_dir).parent().unwrap().parent().unwrap();
    let src = workspace
        .join("examples")
        .join("test_mono_recursive_fn_bug.ail.json");
    let tmp = std::env::temp_dir().join(format!(
        "ailang_mono_recursive_fn_{}",
        std::process::id()
    ));
    std::fs::create_dir_all(&tmp).unwrap();
    let out = tmp.join("bin");

    let build = Command::new(ail_bin())
        .args(["build", src.to_str().unwrap(), "-o"])
        .arg(&out)
        .output()
        .expect("ail build failed to run");
    assert!(
        build.status.success(),
        "ail build failed: stderr={}",
        String::from_utf8_lossy(&build.stderr)
    );

    let run = Command::new(&out).output().expect("execute binary");
    assert!(
        run.status.success(),
        "binary {} exited non-zero",
        out.display()
    );
    // loop(0, 5) = 0 + 5 + 4 + 3 + 2 + 1 = 15
    assert_eq!(
        String::from_utf8(run.stdout).expect("stdout utf8").trim(),
        "15"
    );
}
