RustAst/tests/error_recovery.rs

use myc::ast::nodes::TypedNode;
use myc::ast::environment::Environment;
use myc::ast::types::StaticType;

// Helper: extracts the return type from a compiled node.
// For a function type, returns the return type; otherwise returns the node type directly.
fn get_ret_type(node: &TypedNode) -> StaticType {
    if let StaticType::Function(sig) = &node.ty {
        sig.ret.clone()
    } else {
        node.ty.clone()
    }
}

// --- Type checker errors ---

#[test]
fn test_destructuring_scalar_error() {
    let env = Environment::new();
    let result = env.compile("(def [x] 5)").into_result();
    assert!(result.is_err());
    assert_eq!(
        result.unwrap_err(),
        "Statement 'def' cannot be used as an expression.\nCannot destructure type int as a tuple/vector"
    );
}

#[test]
fn test_call_argument_mismatch() {
    let env = Environment::new();
    // fn takes 1 arg, called with 0
    let result = env.compile("(do (def f (fn [x] x)) (f))").into_result();
    assert!(result.is_err());
    assert!(
        result
            .unwrap_err()
            .contains("no matching overload")
    );
}

#[test]
fn test_destructuring_vector_args() {
    let env = Environment::new();
    // ((fn [[x y]] (+ x y)) [10 20]) -> 30
    let result = env.compile("((fn [[x y]] (+ x y)) [10 20])").into_result();
    assert!(result.is_ok());
    assert_eq!(get_ret_type(&result.unwrap()), StaticType::Int);
}

// --- Error recovery (multi-pass diagnostics) ---

#[test]
fn test_error_recovery_parser() {
    let env = Environment::new();
    // Syntax error: mismatched bracket/paren
    let source = "(do (def a [1 2 ) )";
    let result = env.compile(source);

    assert!(result.diagnostics.has_errors(), "Expected parser errors");
    let error_msgs: Vec<_> = result
        .diagnostics
        .items
        .iter()
        .map(|d| d.message.as_str())
        .collect();

    assert!(
        error_msgs.iter().any(|m| m.contains("RightParen")),
        "Expected error about RightParen"
    );
    assert!(
        result.ast.is_some(),
        "AST should be partially built despite parser errors"
    );
}

#[test]
fn test_error_recovery_binder() {
    let env = Environment::new();
    // Semantic error: undefined variable
    let source = "(do (def a 10) (def b unknown_var) (+ a 5))";
    let result = env.compile(source);

    assert!(result.diagnostics.has_errors(), "Expected binder errors");
    let error_msgs: Vec<_> = result
        .diagnostics
        .items
        .iter()
        .map(|d| d.message.as_str())
        .collect();

    assert!(
        error_msgs
            .iter()
            .any(|m| m.contains("Undefined variable 'unknown_var'")),
        "Expected undefined variable error"
    );
    assert!(result.ast.is_some(), "AST should be built with Error nodes");
}

#[test]
fn test_error_recovery_type_checker() {
    let env = Environment::new();
    // Semantic error: Type mismatch in function call
    let source = "(do (def a 10) (def b (not \"text\")) (- a 2))";
    let result = env.compile(source);

    assert!(
        result.diagnostics.has_errors(),
        "Expected type checker errors"
    );
    let error_msgs: Vec<_> = result
        .diagnostics
        .items
        .iter()
        .map(|d| d.message.as_str())
        .collect();

    assert!(
        error_msgs
            .iter()
            .any(|m| m.contains("no matching overload")),
        "Expected invalid arguments error"
    );
    assert!(result.ast.is_some(), "AST should be built with Error nodes");
}

#[test]
fn test_error_recovery_multiple_errors() {
    let env = Environment::new();
    // A script with multiple errors that should all be collected
    let source = r#"
    (do
        (def a undefined_var)
        (def b (not "text"))
    )
    "#;
    let result = env.compile(source);

    assert!(result.diagnostics.has_errors());
    assert!(
        result.diagnostics.items.len() >= 2,
        "Expected multiple errors to be collected"
    );

    let error_msgs: Vec<_> = result
        .diagnostics
        .items
        .iter()
        .map(|d| d.message.as_str())
        .collect();
    assert!(
        error_msgs
            .iter()
            .any(|m| m.contains("Undefined variable 'undefined_var'"))
    );
    assert!(
        error_msgs
            .iter()
            .any(|m| m.contains("no matching overload"))
    );
}

#[test]
fn test_again_type_mismatch() {
    let env = Environment::new();
    // (again "text") should fail: parameter n is int (from call site), not string.
    // Without this check, the program would loop forever.
    let result = env.run_script(
        r#"(do (def f (fn [n] (if (= n 0) n (again "text")))) (f 3))"#,
    );
    assert!(
        result.is_err(),
        "again with wrong type should be a compile error, not an infinite loop"
    );
}