Bundle and use tl::expected instead of std::expected to support C++20 compilers.

dependencies/tl_expected/expected/tests/assignment.cpp

@@ -0,0 +1,75 @@
+#include <catch2/catch.hpp>
+#include <tl/expected.hpp>
+
+TEST_CASE("Simple assignment", "[assignment.simple]") {
+  tl::expected<int, int> e1 = 42;
+  tl::expected<int, int> e2 = 17;
+  tl::expected<int, int> e3 = 21;
+  tl::expected<int, int> e4 = tl::make_unexpected(42);
+  tl::expected<int, int> e5 = tl::make_unexpected(17);
+  tl::expected<int, int> e6 = tl::make_unexpected(21);
+
+  e1 = e2;
+  REQUIRE(e1);
+  REQUIRE(*e1 == 17);
+  REQUIRE(e2);
+  REQUIRE(*e2 == 17);
+
+  e1 = std::move(e2);
+  REQUIRE(e1);
+  REQUIRE(*e1 == 17);
+  REQUIRE(e2);
+  REQUIRE(*e2 == 17);
+
+  e1 = 42;
+  REQUIRE(e1);
+  REQUIRE(*e1 == 42);
+
+  auto unex = tl::make_unexpected(12);
+  e1 = unex;
+  REQUIRE(!e1);
+  REQUIRE(e1.error() == 12);
+
+  e1 = tl::make_unexpected(42);
+  REQUIRE(!e1);
+  REQUIRE(e1.error() == 42);
+
+  e1 = e3;
+  REQUIRE(e1);
+  REQUIRE(*e1 == 21);
+
+  e4 = e5;
+  REQUIRE(!e4);
+  REQUIRE(e4.error() == 17);
+
+  e4 = std::move(e6);
+  REQUIRE(!e4);
+  REQUIRE(e4.error() == 21);
+
+  e4 = e1;
+  REQUIRE(e4);
+  REQUIRE(*e4 == 21);
+}
+
+TEST_CASE("Assignment deletion", "[assignment.deletion]") {
+  struct has_all {
+    has_all() = default;
+    has_all(const has_all &) = default;
+    has_all(has_all &&) noexcept = default;
+    has_all &operator=(const has_all &) = default;
+  };
+
+  tl::expected<has_all, has_all> e1 = {};
+  tl::expected<has_all, has_all> e2 = {};
+  e1 = e2;
+
+  struct except_move {
+    except_move() = default;
+    except_move(const except_move &) = default;
+    except_move(except_move &&) noexcept(false){};
+    except_move &operator=(const except_move &) = default;
+  };
+  tl::expected<except_move, except_move> e3 = {};
+  tl::expected<except_move, except_move> e4 = {};
+  // e3 = e4; should not compile
+}