Change: mark copy-assignment as deleted for classes with a copy-constructor that is not trivial

This to prevent the default copy-assignment getting used when during the assignment also some other memory needs to be allocated as that would otherwise be freed.

src/error.h

@@ -44,6 +44,9 @@ public:
 	~ErrorMessageData();
 	ErrorMessageData(StringID summary_msg, StringID detailed_msg, uint duration = 0, int x = 0, int y = 0, const GRFFile *textref_stack_grffile = nullptr, uint textref_stack_size = 0, const uint32 *textref_stack = nullptr);
 
+	/* Remove the copy assignment, as the default implementation will not do the right thing. */
+	ErrorMessageData &operator=(ErrorMessageData &rhs) = delete;
+
 	/** Check whether error window shall display a company manager face */
 	bool HasFace() const { return face != INVALID_COMPANY; }
 

src/newgrf_config.h

@@ -113,6 +113,9 @@ struct GRFError {
 	GRFError(StringID severity, StringID message = 0);
 	GRFError(const GRFError &error);
 
+	/* Remove the copy assignment, as the default implementation will not do the right thing. */
+	GRFError &operator=(GRFError &rhs) = delete;
+
 	std::string custom_message; ///< Custom message (if present)
 	std::string data;           ///< Additional data for message and custom_message
 	StringID message;           ///< Default message
@@ -154,6 +157,9 @@ struct GRFConfig : ZeroedMemoryAllocator {
 	GRFConfig(const GRFConfig &config);
 	~GRFConfig();
 
+	/* Remove the copy assignment, as the default implementation will not do the right thing. */
+	GRFConfig &operator=(GRFConfig &rhs) = delete;
+
 	GRFIdentifier ident;                        ///< grfid and md5sum to uniquely identify newgrfs
 	uint8 original_md5sum[16];                  ///< MD5 checksum of original file if only a 'compatible' file was loaded
 	char *filename;                             ///< Filename - either with or without full path