//! Pins the Float-aware `NoInstance` diagnostic added in milestone 23.
//!
//! Property protected: a polymorphic Eq/Ord helper invoked at Float
//! fires `no-instance` (since Float has neither Eq nor Ord instance
//! per design/contracts/float-semantics.md) AND the diagnostic message
//! cross-references the canonical float-semantics contract so the
//! LLM author immediately learns the partial-Float story rather
//! than seeing a bare "no instance" message.

use ailang_check::check_workspace;
use ailang_surface::load_workspace;
use std::path::PathBuf;

fn fixture(name: &str) -> PathBuf {
    PathBuf::from(env!("CARGO_MANIFEST_DIR"))
        .join("../../examples")
        .join(name)
}

#[test]
fn eq_at_float_fires_float_aware_noinstance() {
    let ws = load_workspace(&fixture("eq_float_noinstance.ail")).expect("load");
    let diags = check_workspace(&ws);

    assert!(!diags.is_empty(), "expected NoInstance diagnostic, got none");

    let no_inst = diags
        .iter()
        .find(|d| d.code == "no-instance")
        .unwrap_or_else(|| panic!("expected diagnostic with code 'no-instance', got: {diags:#?}"));

    assert!(
        no_inst.message.contains("Float"),
        "expected Float-aware NoInstance diagnostic, got message: {:?}",
        no_inst.message
    );

    // Cross-ref to the float-semantics contract — the LLM author should
    // be pointed at the canonical explanation of partial Float orderability.
    assert!(
        no_inst.message.contains("design/contracts/float-semantics.md"),
        "expected NoInstance message to cross-reference the float-semantics contract, got: {:?}",
        no_inst.message
    );
}