Merge #19491: util: Make Assert work with any value

fa53635 util: Make Assert work with any value (MarcoFalke)

Pull request description:

  Goal is to avoid compile failures

ACKs for top commit:
  jonatack:
    ACK fa53635
  ryanofsky:
    Code review ACK fa53635. Looks like if argument is an lvalue this effectively does:

Tree-SHA512: a5cf47a8bb2fa1bd8b8895774f33de50ad803165d6f7b520351be1cfcd5612d5d97c51d118461331d30640186c470879e5ad19e3333e09e72685c5e4e4f23079

Author: MarcoFalke

src/test/util_tests.cpp

@@ -41,6 +41,16 @@ namespace BCLog {
 
 BOOST_FIXTURE_TEST_SUITE(util_tests, BasicTestingSetup)
 
+BOOST_AUTO_TEST_CASE(util_check)
+{
+    // Check that Assert can forward
+    const std::unique_ptr<int> p_two = Assert(MakeUnique<int>(2));
+    // Check that Assert works on lvalues and rvalues
+    const int two = *Assert(p_two);
+    Assert(two == 2);
+    Assert(true);
+}
+
 BOOST_AUTO_TEST_CASE(util_criticalsection)
 {
     RecursiveMutex cs;

src/util/check.h

@@ -54,6 +54,6 @@ T get_pure_r_value(T&& val)
 }
 
 /** Identity function. Abort if the value compares equal to zero */
-#define Assert(val) [&]() -> decltype(get_pure_r_value(val))& { auto& check = (val); assert(#val && check); return check; }()
+#define Assert(val) [&]() -> decltype(get_pure_r_value(val)) { auto&& check = (val); assert(#val && check); return std::forward<decltype(get_pure_r_value(val))>(check); }()
 
 #endif // BITCOIN_UTIL_CHECK_H