diff --git a/include/valijson/internal/json_pointer.hpp b/include/valijson/internal/json_pointer.hpp
index 79bb04f..ca978bc 100644
--- a/include/valijson/internal/json_pointer.hpp
+++ b/include/valijson/internal/json_pointer.hpp
@@ -15,13 +15,13 @@ namespace internal {
 namespace json_pointer {
 
 /**
- * @brief   Replace all occurrences of `search` with `replace`. Modifies `subject` in place
+ * @brief   Replace all occurrences of `search` with `replace`. Modifies `subject` in place.
  *
  * @param   subject  string to operate on
  * @param   search   string to search
  * @param   replace  replacement string
  */
-inline void replace_all_inplace(std::string& subject, const char* search,
+inline void replaceAllInPlace(std::string& subject, const char* search,
                                 const char* replace)
 {
     size_t pos = 0;
@@ -94,8 +94,8 @@ inline std::string extractReferenceToken(std::string::const_iterator begin,
     std::string token(begin, end);
 
     // Replace JSON Pointer-specific escaped character sequences
-    replace_all_inplace(token, "~1", "/");
-    replace_all_inplace(token, "~0", "~");
+    replaceAllInPlace(token, "~1", "/");
+    replaceAllInPlace(token, "~0", "~");
 
     // Replace %-encoded character sequences with their actual characters
     for (size_t n = token.find('%'); n != std::string::npos;
diff --git a/include/valijson/validation_visitor.hpp b/include/valijson/validation_visitor.hpp
index 4da2657..7b0ee87 100644
--- a/include/valijson/validation_visitor.hpp
+++ b/include/valijson/validation_visitor.hpp
@@ -967,9 +967,16 @@ public:
         if (!additionalPropertiesSubschema) {
             if (propertiesMatched.size() != target.getObjectSize()) {
                 if (results) {
-                    results->pushError(context, "Object contains properties "
+                    std::string unwanted;
+                    for (const typename AdapterType::ObjectMember m : object) {
+                        if (propertiesMatched.find(m.first) == propertiesMatched.end()) {
+                            unwanted = m.first;
+                            break;
+                        }
+                    }
+                    results->pushError(context, "Object contains a property "
                             "that could not be validated using 'properties' "
-                            "or 'additionalProperties' constraints");
+                            "or 'additionalProperties' constraints: '" + unwanted + "'.");
                 }
 
                 return false;
diff --git a/tests/test_jsoncpp_adapter.cpp b/tests/test_jsoncpp_adapter.cpp
index bd088df..aa8b381 100644
--- a/tests/test_jsoncpp_adapter.cpp
+++ b/tests/test_jsoncpp_adapter.cpp
@@ -12,7 +12,7 @@ TEST_F(TestJsonCppAdapter, BasicArrayIteration)
 {
     const unsigned int numElements = 10;
 
-    // Create a rapidjson document that consists of an array of numbers
+    // Create a jsoncpp document that consists of an array of numbers
     Json::Value document(Json::arrayValue);
     for (unsigned int i = 0; i < numElements; i++) {
         document.append(Json::Value(i));
@@ -46,7 +46,7 @@ TEST_F(TestJsonCppAdapter, BasicObjectIteration)
 {
     const unsigned int numElements = 10;
 
-    // Create a rapidjson document that consists of an object that maps numeric
+    // Create a jsoncpp document that consists of an object that maps numeric
     // strings their corresponding numeric values
     Json::Value document(Json::objectValue);
     for (unsigned int i = 0; i < numElements; i++) {
diff --git a/tests/test_property_tree_adapter.cpp b/tests/test_property_tree_adapter.cpp
index eba84b2..43855dc 100644
--- a/tests/test_property_tree_adapter.cpp
+++ b/tests/test_property_tree_adapter.cpp
@@ -12,7 +12,7 @@ TEST_F(TestPropertyTreeAdapter, BasicArrayIteration)
 {
     const unsigned int numElements = 10;
 
-    // Create a boost property that is equivalent to a JSON array containing a
+    // Create a boost property tree that is equivalent to a JSON array containing a
     // list of numbers.
     boost::property_tree::ptree document;
     for (unsigned int i = 0; i < numElements; i++) {
@@ -50,7 +50,7 @@ TEST_F(TestPropertyTreeAdapter, BasicObjectIteration)
 {
     const unsigned int numElements = 10;
 
-    // Create a rapidjson document that consists of an object that maps numeric
+    // Create a boost property tree that consists of an object that maps numeric
     // strings their corresponding numeric values
     boost::property_tree::ptree document;
     for (unsigned int i = 0; i < numElements; i++) {