nixir/tests/regression_test.cpp

#include "irc/parser.h"
#include "irc/serializer.h"
#include "irc/types.h"
#include <cassert>
#include <iostream>

using namespace nix_irc;

int failures = 0;

#define TEST_CHECK(cond, msg)                                                                      \
  do {                                                                                             \
    if (!(cond)) {                                                                                 \
      std::cerr << "  FAIL: " << msg << std::endl;                                                 \
      failures++;                                                                                  \
    } else {                                                                                       \
      std::cout << "  PASS: " << msg << std::endl;                                                 \
    }                                                                                              \
  } while (0)

#define TEST_PASS(msg) std::cout << "  PASS: " << msg << std::endl
#define TEST_FAIL(msg)                                                                             \
  do {                                                                                             \
    std::cerr << "  FAIL: " << msg << std::endl;                                                   \
    failures++;                                                                                    \
  } while (0)

void test_enum_compatibility() {
  std::cout << "> Enum compatibility..." << std::endl;

  if (static_cast<uint8_t>(NodeType::WITH) == 0x32) {
    std::cout << "  PASS: WITH has correct value 0x32" << std::endl;
  } else {
    std::cerr << "  FAIL: WITH should be 0x32, got " << static_cast<uint8_t>(NodeType::WITH)
              << std::endl;
  }

  if (static_cast<uint8_t>(NodeType::HAS_ATTR) == 0x34) {
    std::cout << "  PASS: HAS_ATTR has value 0x34 (new slot after WITH bump)" << std::endl;
  } else if (static_cast<uint8_t>(NodeType::HAS_ATTR) == 0x33 &&
             static_cast<uint8_t>(NodeType::WITH) == 0x32) {
    std::cout << "  PASS: HAS_ATTR has value 0x33 (restored original with WITH "
                 "at 0x32)"
              << std::endl;
  } else {
    std::cerr << "  FAIL: HAS_ATTR value is " << static_cast<uint8_t>(NodeType::HAS_ATTR)
              << " (expected 0x34 or 0x33 with WITH=0x32)" << std::endl;
  }

  if (IR_VERSION == 3) {
    std::cout << "  PASS: IR_VERSION is 3" << std::endl;
  } else {
    std::cerr << "  FAIL: IR_VERSION should be 3, got " << IR_VERSION << std::endl;
    failures++;
  }
}

void test_serializer_select_with_default() {
  std::cout << "> SELECT serialization with default_expr..." << std::endl;

  auto expr = std::make_shared<Node>(ConstIntNode(42));
  auto attr = std::make_shared<Node>(ConstStringNode("key"));
  auto default_val = std::make_shared<Node>(ConstIntNode(100));

  SelectNode select_node(expr, attr);
  select_node.default_expr = default_val;
  auto select = std::make_shared<Node>(select_node);

  IRModule module;
  module.entry = select;

  Serializer ser;
  auto bytes = ser.serialize_to_bytes(module);

  Deserializer deser;
  auto loaded = deser.deserialize(bytes);

  auto* loaded_select = loaded.entry->get_if<SelectNode>();
  if (loaded_select && loaded_select->default_expr && *loaded_select->default_expr) {
    auto* def_val = (*loaded_select->default_expr)->get_if<ConstIntNode>();
    if (def_val && def_val->value == 100) {
      std::cout << "  PASS: SELECT with default_expr round-trips correctly" << std::endl;
    } else {
      std::cerr << "  FAIL: default_expr value incorrect" << std::endl;
    }
  } else {
    std::cerr << "  FAIL: default_expr not deserialized (missing u8 flag read)" << std::endl;
  }
}

void test_serializer_select_without_default() {
  std::cout << "> SELECT serialization without default_expr..." << std::endl;

  auto expr = std::make_shared<Node>(ConstIntNode(42));
  auto attr = std::make_shared<Node>(ConstStringNode("key"));

  SelectNode select_node(expr, attr);
  auto select = std::make_shared<Node>(select_node);

  IRModule module;
  module.entry = select;

  Serializer ser;
  auto bytes = ser.serialize_to_bytes(module);

  Deserializer deser;
  auto loaded = deser.deserialize(bytes);

  auto* loaded_select = loaded.entry->get_if<SelectNode>();
  if (loaded_select && (!loaded_select->default_expr || !*loaded_select->default_expr)) {
    std::cout << "  PASS: SELECT without default_expr round-trips correctly" << std::endl;
  } else {
    std::cerr << "  FAIL: default_expr should be null/absent" << std::endl;
  }
}

void test_parser_brace_depth_in_strings() {
  std::cout << "> Parser brace depth handling in strings..." << std::endl;

  std::string test_input = R"(let s = "test}"; in s)";

  try {
    Parser parser;
    auto ast = parser.parse(test_input);
    TEST_PASS("Brace inside string does not confuse parser");
  } catch (const std::exception& e) {
    TEST_FAIL("Parser should handle '}' inside strings");
  }
}

void test_parser_has_ellipsis_usage() {
  std::cout << "> Parser has_ellipsis usage..." << std::endl;

  std::string with_ellipsis = "{ a, ... }: a";
  std::string without_ellipsis = "{ a, b }: a + b";

  try {
    Parser parser1;
    auto ast1 = parser1.parse(with_ellipsis);
    TEST_PASS("Pattern with ellipsis parses correctly");

    Parser parser2;
    auto ast2 = parser2.parse(without_ellipsis);
    TEST_PASS("Pattern without ellipsis parses correctly");
  } catch (const std::exception& e) {
    TEST_FAIL("Pattern parsing failed");
  }
}

void test_parser_expect_in_speculative_parsing() {
  std::cout << "> Parser expect() in speculative parsing..." << std::endl;

  std::string not_a_lambda = "1 + 2";
  std::string actual_lambda = "x: x + 1";

  try {
    Parser parser1;
    auto ast1 = parser1.parse(not_a_lambda);
    TEST_PASS("Non-lambda input does not cause parser to throw");

    Parser parser2;
    auto ast2 = parser2.parse(actual_lambda);
    TEST_PASS("Actual lambda parses correctly");
  } catch (const std::exception& e) {
    TEST_FAIL("Parser should handle both lambda and non-lambda input");
  }
}

void test_lookup_path_node() {
  std::cout << "> Lookup path serialization..." << std::endl;

  auto lookup = std::make_shared<Node>(ConstLookupPathNode("nixpkgs"));
  IRModule module;
  module.entry = lookup;

  Serializer ser;
  auto bytes = ser.serialize_to_bytes(module);

  Deserializer deser;
  auto loaded = deser.deserialize(bytes);

  auto* loaded_lookup = loaded.entry->get_if<ConstLookupPathNode>();
  TEST_CHECK(loaded_lookup != nullptr, "Deserialized node is ConstLookupPathNode");
  TEST_CHECK(loaded_lookup && loaded_lookup->value == "nixpkgs", "Lookup path value is 'nixpkgs'");
}

void test_import_node() {
  std::cout << "> Import node serialization..." << std::endl;

  auto path = std::make_shared<Node>(ConstPathNode("./test.nix"));
  auto import_node = std::make_shared<Node>(ImportNode(path));
  IRModule module;
  module.entry = import_node;

  Serializer ser;
  auto bytes = ser.serialize_to_bytes(module);

  Deserializer deser;
  auto loaded = deser.deserialize(bytes);

  auto* loaded_import = loaded.entry->get_if<ImportNode>();
  TEST_CHECK(loaded_import != nullptr, "Deserialized node is ImportNode");
  TEST_CHECK(loaded_import && loaded_import->path != nullptr, "Import node has path");

  if (loaded_import && loaded_import->path) {
    auto* path_node = loaded_import->path->get_if<ConstPathNode>();
    TEST_CHECK(path_node != nullptr, "Import path is ConstPathNode");
    TEST_CHECK(path_node && path_node->value == "./test.nix", "Import path value is './test.nix'");
  }
}

void test_import_with_lookup_path() {
  std::cout << "> Import with lookup path..." << std::endl;

  auto lookup = std::make_shared<Node>(ConstLookupPathNode("nixpkgs"));
  auto import_node = std::make_shared<Node>(ImportNode(lookup));
  IRModule module;
  module.entry = import_node;

  Serializer ser;
  auto bytes = ser.serialize_to_bytes(module);

  Deserializer deser;
  auto loaded = deser.deserialize(bytes);

  auto* loaded_import = loaded.entry->get_if<ImportNode>();
  TEST_CHECK(loaded_import != nullptr, "Deserialized node is ImportNode");

  if (loaded_import && loaded_import->path) {
    auto* lookup_node = loaded_import->path->get_if<ConstLookupPathNode>();
    TEST_CHECK(lookup_node != nullptr, "Import path is ConstLookupPathNode");
    TEST_CHECK(lookup_node && lookup_node->value == "nixpkgs", "Lookup path value is 'nixpkgs'");
  }
}

void test_uri_node() {
  std::cout << "> URI node serialization..." << std::endl;

  auto uri = std::make_shared<Node>(ConstURINode("https://example.com"));
  IRModule module;
  module.entry = uri;

  Serializer ser;
  auto bytes = ser.serialize_to_bytes(module);

  Deserializer deser;
  auto loaded = deser.deserialize(bytes);

  auto* loaded_uri = loaded.entry->get_if<ConstURINode>();
  TEST_CHECK(loaded_uri != nullptr, "Deserialized node is ConstURINode");
  TEST_CHECK(loaded_uri && loaded_uri->value == "https://example.com",
             "URI value is 'https://example.com'");
}

void test_float_node() {
  std::cout << "> Float node serialization..." << std::endl;

  auto float_val = std::make_shared<Node>(ConstFloatNode(3.14159));
  IRModule module;
  module.entry = float_val;

  Serializer ser;
  auto bytes = ser.serialize_to_bytes(module);

  Deserializer deser;
  auto loaded = deser.deserialize(bytes);

  auto* loaded_float = loaded.entry->get_if<ConstFloatNode>();
  TEST_CHECK(loaded_float != nullptr, "Deserialized node is ConstFloatNode");
  TEST_CHECK(loaded_float && loaded_float->value > 3.14 && loaded_float->value < 3.15,
             "Float value is approximately 3.14159");
}

// LambdaPatternNode Tests
void test_lambda_pattern_simple() {
  std::cout << "> LambdaPatternNode simple ({ a, b }: a + b)..." << std::endl;

  // Body: a + b (using VarNode for a and b)
  auto var_a = std::make_shared<Node>(VarNode(0, "a"));
  auto var_b = std::make_shared<Node>(VarNode(0, "b"));
  auto body = std::make_shared<Node>(BinaryOpNode(BinaryOp::ADD, var_a, var_b));

  // Create lambda pattern with two required fields
  LambdaPatternNode lambda_pattern(body);
  lambda_pattern.required_fields.emplace_back("a", std::nullopt);
  lambda_pattern.required_fields.emplace_back("b", std::nullopt);
  lambda_pattern.allow_extra = false;

  auto node = std::make_shared<Node>(std::move(lambda_pattern));

  // Serialize
  IRModule module;
  module.entry = node;
  Serializer ser;
  auto bytes = ser.serialize_to_bytes(module);

  // Deserialize
  Deserializer deser;
  auto loaded = deser.deserialize(bytes);

  // Verify
  auto* loaded_node = loaded.entry->get_if<LambdaPatternNode>();
  TEST_CHECK(loaded_node != nullptr, "Type is LambdaPatternNode");
  TEST_CHECK(loaded_node && loaded_node->required_fields.size() == 2, "Has 2 required fields");
  TEST_CHECK(loaded_node && loaded_node->optional_fields.size() == 0, "Has 0 optional fields");
  TEST_CHECK(loaded_node && loaded_node->required_fields[0].name == "a", "First field is 'a'");
  TEST_CHECK(loaded_node && loaded_node->required_fields[1].name == "b", "Second field is 'b'");
  TEST_CHECK(loaded_node && !loaded_node->at_binding.has_value(), "No at-binding");
  TEST_CHECK(loaded_node && !loaded_node->allow_extra, "No ellipsis");
  TEST_CHECK(loaded_node && loaded_node->body != nullptr, "Has body");
}

void test_lambda_pattern_with_defaults() {
  std::cout << "> LambdaPatternNode with defaults ({ a, b ? 10 }: a + b)..." << std::endl;

  // Default value for b
  auto default_b = std::make_shared<Node>(ConstIntNode(10));

  // Body: a + b
  auto var_a = std::make_shared<Node>(VarNode(0, "a"));
  auto var_b = std::make_shared<Node>(VarNode(0, "b"));
  auto body = std::make_shared<Node>(BinaryOpNode(BinaryOp::ADD, var_a, var_b));

  // Create lambda pattern
  LambdaPatternNode lambda_pattern(body);
  lambda_pattern.required_fields.emplace_back("a", std::nullopt);
  lambda_pattern.optional_fields.emplace_back("b", default_b);
  lambda_pattern.allow_extra = false;

  auto node = std::make_shared<Node>(std::move(lambda_pattern));

  // Serialize
  IRModule module;
  module.entry = node;
  Serializer ser;
  auto bytes = ser.serialize_to_bytes(module);

  // Deserialize
  Deserializer deser;
  auto loaded = deser.deserialize(bytes);

  // Verify
  auto* loaded_node = loaded.entry->get_if<LambdaPatternNode>();
  TEST_CHECK(loaded_node != nullptr, "Type is LambdaPatternNode");
  TEST_CHECK(loaded_node && loaded_node->required_fields.size() == 1, "Has 1 required field");
  TEST_CHECK(loaded_node && loaded_node->optional_fields.size() == 1, "Has 1 optional field");
  TEST_CHECK(loaded_node && loaded_node->required_fields[0].name == "a", "Required field is 'a'");
  TEST_CHECK(loaded_node && loaded_node->optional_fields[0].name == "b", "Optional field is 'b'");
  TEST_CHECK(loaded_node && loaded_node->optional_fields[0].default_value.has_value(),
             "Optional field has default");

  if (loaded_node && loaded_node->optional_fields[0].default_value) {
    auto* def_val = (*loaded_node->optional_fields[0].default_value)->get_if<ConstIntNode>();
    TEST_CHECK(def_val && def_val->value == 10, "Default value is 10");
  }
}

void test_lambda_pattern_at_binding() {
  std::cout << "> LambdaPatternNode with at-binding (args@{ a, b }: args.a)..." << std::endl;

  // Body: args.a (select expression)
  auto var_args = std::make_shared<Node>(VarNode(0, "args"));
  auto attr = std::make_shared<Node>(ConstStringNode("a"));
  auto body = std::make_shared<Node>(SelectNode(var_args, attr));

  // Create lambda pattern with at-binding
  LambdaPatternNode lambda_pattern(body);
  lambda_pattern.required_fields.emplace_back("a", std::nullopt);
  lambda_pattern.required_fields.emplace_back("b", std::nullopt);
  lambda_pattern.at_binding = "args";
  lambda_pattern.allow_extra = false;

  auto node = std::make_shared<Node>(std::move(lambda_pattern));

  // Serialize
  IRModule module;
  module.entry = node;
  Serializer ser;
  auto bytes = ser.serialize_to_bytes(module);

  // Deserialize
  Deserializer deser;
  auto loaded = deser.deserialize(bytes);

  // Verify
  auto* loaded_node = loaded.entry->get_if<LambdaPatternNode>();
  TEST_CHECK(loaded_node != nullptr, "Type is LambdaPatternNode");
  TEST_CHECK(loaded_node && loaded_node->at_binding.has_value(), "Has at-binding");
  TEST_CHECK(loaded_node && loaded_node->at_binding.value() == "args", "At-binding is 'args'");
}

void test_lambda_pattern_ellipsis() {
  std::cout << "> LambdaPatternNode with ellipsis ({ a, ... }: a)..." << std::endl;

  // Body: a
  auto body = std::make_shared<Node>(VarNode(0, "a"));

  // Create lambda pattern with ellipsis
  LambdaPatternNode lambda_pattern(body);
  lambda_pattern.required_fields.emplace_back("a", std::nullopt);
  lambda_pattern.allow_extra = true;

  auto node = std::make_shared<Node>(std::move(lambda_pattern));

  // Serialize
  IRModule module;
  module.entry = node;
  Serializer ser;
  auto bytes = ser.serialize_to_bytes(module);

  // Deserialize
  Deserializer deser;
  auto loaded = deser.deserialize(bytes);

  // Verify
  auto* loaded_node = loaded.entry->get_if<LambdaPatternNode>();
  TEST_CHECK(loaded_node != nullptr, "Type is LambdaPatternNode");
  TEST_CHECK(loaded_node && loaded_node->allow_extra, "Has ellipsis (allow_extra=true)");
}

void test_lambda_pattern_complete() {
  std::cout << "> LambdaPatternNode complete (args@{ a, b ? 5, ... }: body)..." << std::endl;

  // Default value for b
  auto default_b = std::make_shared<Node>(ConstIntNode(5));

  // Body: simple var
  auto body = std::make_shared<Node>(VarNode(0, "x"));

  // Create lambda pattern with all features
  LambdaPatternNode lambda_pattern(body);
  lambda_pattern.required_fields.emplace_back("a", std::nullopt);
  lambda_pattern.optional_fields.emplace_back("b", default_b);
  lambda_pattern.at_binding = "args";
  lambda_pattern.allow_extra = true;

  auto node = std::make_shared<Node>(std::move(lambda_pattern));

  // Serialize
  IRModule module;
  module.entry = node;
  Serializer ser;
  auto bytes = ser.serialize_to_bytes(module);

  // Deserialize
  Deserializer deser;
  auto loaded = deser.deserialize(bytes);

  // Verify all fields
  auto* loaded_node = loaded.entry->get_if<LambdaPatternNode>();
  TEST_CHECK(loaded_node != nullptr, "Type is LambdaPatternNode");
  TEST_CHECK(loaded_node && loaded_node->required_fields.size() == 1, "Has 1 required field");
  TEST_CHECK(loaded_node && loaded_node->optional_fields.size() == 1, "Has 1 optional field");
  TEST_CHECK(loaded_node && loaded_node->at_binding.has_value(), "Has at-binding");
  TEST_CHECK(loaded_node && loaded_node->at_binding.value() == "args", "At-binding is 'args'");
  TEST_CHECK(loaded_node && loaded_node->allow_extra, "Has ellipsis");
}

void test_lambda_pattern_empty() {
  std::cout << "> LambdaPatternNode empty ({ }: body)..." << std::endl;

  // Body: simple constant
  auto body = std::make_shared<Node>(ConstIntNode(42));

  // Create empty lambda pattern
  LambdaPatternNode lambda_pattern(body);
  lambda_pattern.allow_extra = false;

  auto node = std::make_shared<Node>(std::move(lambda_pattern));

  // Serialize
  IRModule module;
  module.entry = node;
  Serializer ser;
  auto bytes = ser.serialize_to_bytes(module);

  // Deserialize
  Deserializer deser;
  auto loaded = deser.deserialize(bytes);

  // Verify
  auto* loaded_node = loaded.entry->get_if<LambdaPatternNode>();
  TEST_CHECK(loaded_node != nullptr, "Type is LambdaPatternNode");
  TEST_CHECK(loaded_node && loaded_node->required_fields.size() == 0, "Has 0 required fields");
  TEST_CHECK(loaded_node && loaded_node->optional_fields.size() == 0, "Has 0 optional fields");
  TEST_CHECK(loaded_node && !loaded_node->at_binding.has_value(), "No at-binding");
  TEST_CHECK(loaded_node && !loaded_node->allow_extra, "No ellipsis");
}

// StringInterpolationNode Tests

void test_string_interpolation_simple() {
  std::cout << "> StringInterpolationNode simple (\"hello ${name}\")..." << std::endl;

  // "hello ${name}" = literal "hello " + expr(name)
  std::vector<StringPart> parts;
  parts.push_back(StringPart::make_literal("hello "));
  parts.push_back(StringPart::make_expr(std::make_shared<Node>(VarNode(0, "name"))));

  auto node = std::make_shared<Node>(StringInterpolationNode(std::move(parts)));

  // Serialize
  IRModule module;
  module.entry = node;
  Serializer ser;
  auto bytes = ser.serialize_to_bytes(module);

  // Deserialize
  Deserializer deser;
  auto loaded = deser.deserialize(bytes);

  // Verify
  auto* loaded_node = loaded.entry->get_if<StringInterpolationNode>();
  TEST_CHECK(loaded_node != nullptr, "Type is StringInterpolationNode");
  TEST_CHECK(loaded_node && loaded_node->parts.size() == 2, "Has 2 parts");
  TEST_CHECK(loaded_node && loaded_node->parts[0].type == StringPart::Type::LITERAL,
             "First part is LITERAL");
  TEST_CHECK(loaded_node && loaded_node->parts[0].literal == "hello ", "First part is 'hello '");
  TEST_CHECK(loaded_node && loaded_node->parts[1].type == StringPart::Type::EXPR,
             "Second part is EXPR");
  TEST_CHECK(loaded_node && loaded_node->parts[1].expr != nullptr, "Second part has expression");
}

void test_string_interpolation_multiple() {
  std::cout << "> StringInterpolationNode multiple (\"${a} and ${b}\")..." << std::endl;

  // "${a} and ${b}" = expr(a) + literal " and " + expr(b)
  std::vector<StringPart> parts;
  parts.push_back(StringPart::make_expr(std::make_shared<Node>(VarNode(0, "a"))));
  parts.push_back(StringPart::make_literal(" and "));
  parts.push_back(StringPart::make_expr(std::make_shared<Node>(VarNode(0, "b"))));

  auto node = std::make_shared<Node>(StringInterpolationNode(std::move(parts)));

  // Serialize
  IRModule module;
  module.entry = node;
  Serializer ser;
  auto bytes = ser.serialize_to_bytes(module);

  // Deserialize
  Deserializer deser;
  auto loaded = deser.deserialize(bytes);

  // Verify
  auto* loaded_node = loaded.entry->get_if<StringInterpolationNode>();
  TEST_CHECK(loaded_node != nullptr, "Type is StringInterpolationNode");
  TEST_CHECK(loaded_node && loaded_node->parts.size() == 3, "Has 3 parts");
  TEST_CHECK(loaded_node && loaded_node->parts[0].type == StringPart::Type::EXPR, "Part 0 is EXPR");
  TEST_CHECK(loaded_node && loaded_node->parts[1].type == StringPart::Type::LITERAL,
             "Part 1 is LITERAL");
  TEST_CHECK(loaded_node && loaded_node->parts[1].literal == " and ", "Part 1 is ' and '");
  TEST_CHECK(loaded_node && loaded_node->parts[2].type == StringPart::Type::EXPR, "Part 2 is EXPR");
}

void test_string_interpolation_complex() {
  std::cout << "> StringInterpolationNode complex (\"result: ${a + b}\")..." << std::endl;

  // "result: ${a + b}" = literal "result: " + expr(a + b)
  auto expr_a = std::make_shared<Node>(VarNode(0, "a"));
  auto expr_b = std::make_shared<Node>(VarNode(0, "b"));
  auto add_expr = std::make_shared<Node>(BinaryOpNode(BinaryOp::ADD, expr_a, expr_b));

  std::vector<StringPart> parts;
  parts.push_back(StringPart::make_literal("result: "));
  parts.push_back(StringPart::make_expr(add_expr));

  auto node = std::make_shared<Node>(StringInterpolationNode(std::move(parts)));

  // Serialize
  IRModule module;
  module.entry = node;
  Serializer ser;
  auto bytes = ser.serialize_to_bytes(module);

  // Deserialize
  Deserializer deser;
  auto loaded = deser.deserialize(bytes);

  // Verify
  auto* loaded_node = loaded.entry->get_if<StringInterpolationNode>();
  TEST_CHECK(loaded_node != nullptr, "Type is StringInterpolationNode");
  TEST_CHECK(loaded_node && loaded_node->parts.size() == 2, "Has 2 parts");
  TEST_CHECK(loaded_node && loaded_node->parts[1].type == StringPart::Type::EXPR, "Part 1 is EXPR");

  // Verify the expression is a BinaryOpNode
  if (loaded_node && loaded_node->parts[1].expr) {
    auto* bin_op = loaded_node->parts[1].expr->get_if<BinaryOpNode>();
    TEST_CHECK(bin_op != nullptr, "Expression is BinaryOpNode");
    TEST_CHECK(bin_op && bin_op->op == BinaryOp::ADD, "Operation is ADD");
  }
}

void test_string_interpolation_nested() {
  std::cout << "> StringInterpolationNode nested (\"${prefix}/${path}\")..." << std::endl;

  // "${prefix}/${path}" = expr(prefix) + literal "/" + expr(path)
  std::vector<StringPart> parts;
  parts.push_back(StringPart::make_expr(std::make_shared<Node>(VarNode(0, "prefix"))));
  parts.push_back(StringPart::make_literal("/"));
  parts.push_back(StringPart::make_expr(std::make_shared<Node>(VarNode(0, "path"))));

  auto node = std::make_shared<Node>(StringInterpolationNode(std::move(parts)));

  // Serialize
  IRModule module;
  module.entry = node;
  Serializer ser;
  auto bytes = ser.serialize_to_bytes(module);

  // Deserialize
  Deserializer deser;
  auto loaded = deser.deserialize(bytes);

  // Verify
  auto* loaded_node = loaded.entry->get_if<StringInterpolationNode>();
  TEST_CHECK(loaded_node != nullptr, "Type is StringInterpolationNode");
  TEST_CHECK(loaded_node && loaded_node->parts.size() == 3, "Has 3 parts");
  TEST_CHECK(loaded_node && loaded_node->parts[1].type == StringPart::Type::LITERAL,
             "Middle part is LITERAL");
  TEST_CHECK(loaded_node && loaded_node->parts[1].literal == "/", "Middle part is '/'");
}

int main() {
  std::cout << "=== Regression Tests ===" << std::endl << std::endl;

  test_enum_compatibility();
  std::cout << std::endl;

  test_serializer_select_with_default();
  std::cout << std::endl;

  test_serializer_select_without_default();
  std::cout << std::endl;

  test_parser_brace_depth_in_strings();
  std::cout << std::endl;

  test_parser_has_ellipsis_usage();
  std::cout << std::endl;

  test_parser_expect_in_speculative_parsing();
  std::cout << std::endl;

  test_lookup_path_node();
  std::cout << std::endl;

  test_import_node();
  std::cout << std::endl;

  test_import_with_lookup_path();
  std::cout << std::endl;

  test_uri_node();
  std::cout << std::endl;

  test_float_node();
  std::cout << std::endl;

  test_lambda_pattern_simple();
  std::cout << std::endl;

  test_lambda_pattern_with_defaults();
  std::cout << std::endl;

  test_lambda_pattern_at_binding();
  std::cout << std::endl;

  test_lambda_pattern_ellipsis();
  std::cout << std::endl;

  test_lambda_pattern_complete();
  std::cout << std::endl;

  test_lambda_pattern_empty();
  std::cout << std::endl;

  test_string_interpolation_simple();
  std::cout << std::endl;

  test_string_interpolation_multiple();
  std::cout << std::endl;

  test_string_interpolation_complex();
  std::cout << std::endl;

  test_string_interpolation_nested();
  std::cout << std::endl;

  std::cout << "=== Tests Complete ===" << std::endl;
  std::cout << "Failures: " << failures << std::endl;
  return failures > 0 ? 1 : 0;
}