Fixed issue: Invalid escape sequences in string literals not raising errors (e.g. \q)

core/src/main/java/org/luaj/vm2/compiler/LexState.java

@@ -552,9 +552,12 @@ public class LexState extends Constants {
 							continue;
 						}
 						default: {
-							if (!isdigit(current))
-								save_and_next(); /* handles \\, \", \', and \? */
-							else { /* \xxx */
+							if (!isdigit(current)) {
+								if (current == '\\' || current == '"' || current == '\'')
+									save_and_next();
+								else
+									lexerror("invalid escape sequence", TK_STRING);
+							} else { /* \xxx */
 								int i = 0;
 								c = 0;
 								do {
@@ -2150,4 +2153,4 @@ public class LexState extends Constants {
 
 	/* }====================================================================== */
 
-}
+}