Print also resource key when attempting to overwrite final resource.

src/ResourceManager.h

@@ -157,7 +157,7 @@ namespace Implementation {
 
                 /* Cannot change resource with already final state */
                 CORRADE_ASSERT(it == _data.end() || it->second.state != ResourceDataState::Final,
-                    "ResourceManager::set(): cannot change already final resource", );
+                    "ResourceManager::set(): cannot change already final resource" << key, );
 
                 /* If nothing is referencing reference-counted resource, we're done */
                 if(policy == ResourcePolicy::ReferenceCounted && (it == _data.end() || it->second.referenceCount == 0)) {

src/Test/ResourceManagerTest.cpp

@@ -162,7 +162,7 @@ void ResourceManagerTest::basic() {
     Error::setOutput(&out);
     rm.set(answerKey, new std::int32_t(43), ResourceDataState::Mutable, ResourcePolicy::Resident);
     CORRADE_COMPARE(*theAnswer, 42);
-    CORRADE_COMPARE(out.str(), "ResourceManager::set(): cannot change already final resource\n");
+    CORRADE_COMPARE(out.str(), "ResourceManager::set(): cannot change already final resource " + answerKey.hexString() + '\n');
 
     /* But non-final can be changed */
     rm.set(questionKey, new std::int32_t(20), ResourceDataState::Final, ResourcePolicy::Resident);