diff --git a/src/saveload/saveload.h b/src/saveload/saveload.h
index 6f49cda7ed..6ac242cb70 100644
--- a/src/saveload/saveload.h
+++ b/src/saveload/saveload.h
@@ -741,6 +741,54 @@ static inline constexpr bool IsNumericType(VarType conv)
 	return GetVarMemType(conv) <= SLE_VAR_U64;
 }
 
+/**
+ * Return expect size in bytes of a VarType
+ * @param type VarType to get size of.
+ * @return size of type in bytes.
+ */
+static inline constexpr size_t SlVarSize(VarType type)
+{
+	switch (GetVarMemType(type)) {
+		case SLE_VAR_BL: return sizeof(bool);
+		case SLE_VAR_I8: return sizeof(int8_t);
+		case SLE_VAR_U8: return sizeof(uint8_t);
+		case SLE_VAR_I16: return sizeof(int16_t);
+		case SLE_VAR_U16: return sizeof(uint16_t);
+		case SLE_VAR_I32: return sizeof(int32_t);
+		case SLE_VAR_U32: return sizeof(uint32_t);
+		case SLE_VAR_I64: return sizeof(int64_t);
+		case SLE_VAR_U64: return sizeof(uint64_t);
+		case SLE_VAR_NULL: return sizeof(void *);
+		case SLE_VAR_STR: return sizeof(std::string);
+		case SLE_VAR_STRQ: return sizeof(std::string);
+		case SLE_VAR_NAME: return sizeof(std::string);
+		default: NOT_REACHED();
+	}
+}
+
+/**
+ * Check if a saveload cmd/type/length entry matches the size of the variable.
+ * @param cmd SaveLoadType of entry.
+ * @param type VarType of entry.
+ * @param length Array length of entry.
+ * @param size Actual size of variable.
+ * @return true iff the sizes match.
+ */
+static inline constexpr bool SlCheckVarSize(SaveLoadType cmd, VarType type, size_t length, size_t size)
+{
+	switch (cmd) {
+		case SL_VAR: return SlVarSize(type) == size;
+		case SL_REF: return sizeof(void *) == size;
+		case SL_STDSTR: return SlVarSize(type) == size;
+		case SL_ARR: return SlVarSize(type) * length <= size; // Partial load of array is permitted.
+		case SL_DEQUE: return sizeof(std::deque<void *>) == size;
+		case SL_VECTOR: return sizeof(std::vector<void *>) == size;
+		case SL_REFLIST: return sizeof(std::list<void *>) == size;
+		case SL_SAVEBYTE: return true;
+		default: NOT_REACHED();
+	}
+}
+
 /**
  * Storage of simple variables, references (pointers), and arrays.
  * @param cmd      Load/save type. @see SaveLoadType
@@ -748,12 +796,18 @@ static inline constexpr bool IsNumericType(VarType conv)
  * @param base     Name of the class or struct containing the variable.
  * @param variable Name of the variable in the class or struct referenced by \a base.
  * @param type     Storage of the data in memory and in the savegame.
+ * @param length   Number of elements in the array.
  * @param from     First savegame version that has the field.
  * @param to       Last savegame version that has the field.
  * @param extra    Extra data to pass to the address callback function.
  * @note In general, it is better to use one of the SLE_* macros below.
  */
-#define SLE_GENERAL_NAME(cmd, name, base, variable, type, length, from, to, extra) SaveLoad {name, cmd, type, length, from, to, cpp_sizeof(base, variable), [] (void *b, size_t) -> void * { assert(b != nullptr); return const_cast<void *>(static_cast<const void *>(std::addressof(static_cast<base *>(b)->variable))); }, extra, nullptr}
+#define SLE_GENERAL_NAME(cmd, name, base, variable, type, length, from, to, extra) \
+	SaveLoad {name, cmd, type, length, from, to, cpp_sizeof(base, variable), [] (void *b, size_t) -> void * { \
+		static_assert(SlCheckVarSize(cmd, type, length, sizeof(static_cast<base *>(b)->variable))); \
+		assert(b != nullptr); \
+		return const_cast<void *>(static_cast<const void *>(std::addressof(static_cast<base *>(b)->variable))); \
+	}, extra, nullptr}
 
 /**
  * Storage of simple variables, references (pointers), and arrays with a custom name.
@@ -761,6 +815,7 @@ static inline constexpr bool IsNumericType(VarType conv)
  * @param base     Name of the class or struct containing the variable.
  * @param variable Name of the variable in the class or struct referenced by \a base.
  * @param type     Storage of the data in memory and in the savegame.
+ * @param length   Number of elements in the array.
  * @param from     First savegame version that has the field.
  * @param to       Last savegame version that has the field.
  * @param extra    Extra data to pass to the address callback function.
@@ -966,7 +1021,10 @@ static inline constexpr bool IsNumericType(VarType conv)
  * @param extra    Extra data to pass to the address callback function.
  * @note In general, it is better to use one of the SLEG_* macros below.
  */
-#define SLEG_GENERAL(name, cmd, variable, type, length, from, to, extra) SaveLoad {name, cmd, type, length, from, to, sizeof(variable), [] (void *, size_t) -> void * { return static_cast<void *>(std::addressof(variable)); }, extra, nullptr}
+#define SLEG_GENERAL(name, cmd, variable, type, length, from, to, extra) \
+	SaveLoad {name, cmd, type, length, from, to, sizeof(variable), [] (void *, size_t) -> void * { \
+		static_assert(SlCheckVarSize(cmd, type, length, sizeof(variable))); \
+		return static_cast<void *>(std::addressof(variable)); }, extra, nullptr}
 
 /**
  * Storage of a global variable in some savegame versions.