Remove unnecessary code and add some error explanations

core/os/dir_access.cpp

@@ -43,8 +43,6 @@ String DirAccess::_get_root_path() const {
 		case ACCESS_USERDATA: return OS::get_singleton()->get_user_data_dir();
 		default: return "";
 	}
-
-	return "";
 }
 String DirAccess::_get_root_string() const {
 
@@ -54,8 +52,6 @@ String DirAccess::_get_root_string() const {
 		case ACCESS_USERDATA: return "user://";
 		default: return "";
 	}
-
-	return "";
 }
 
 int DirAccess::get_current_drive() {

core/os/memory.h

@@ -66,7 +66,7 @@ public:
 class DefaultAllocator {
 public:
 	_FORCE_INLINE_ static void *alloc(size_t p_memory) { return Memory::alloc_static(p_memory, false); }
-	_FORCE_INLINE_ static void free(void *p_ptr) { return Memory::free_static(p_ptr, false); }
+	_FORCE_INLINE_ static void free(void *p_ptr) { Memory::free_static(p_ptr, false); }
 };
 
 void *operator new(size_t p_size, const char *p_description); ///< operator new that takes a description and uses MemoryStaticPool