FIX: Remove the DO keyword from PARSE

fixes: Oldes/Rebol-issues#2083
related: Oldes/Rebol-issues#2085

DO rule was not working properly and as a confusing, I agree with Ladislav and disable it for now. (The current `Do_Eval_Rule` code can be enabled using the `USE_DO_PARSE_RULE` define)

Author: Oldes

src/core/u-parse.c

@@ -559,7 +559,8 @@ void Print_Parse_Index(REBCNT type, REBVAL *rules, REBSER *series, REBCNT index)
 	return i;
 }
 
-
+#ifdef USE_DO_PARSE_RULE
+//@@ https://github.com/Oldes/Rebol-issues/issues/2083
 /***********************************************************************
 **
 */	static REBCNT Do_Eval_Rule(REBPARSE *parse, REBCNT index, REBVAL **rule)
@@ -653,7 +654,7 @@ void Print_Parse_Index(REBCNT type, REBVAL *rules, REBSER *series, REBCNT index)
 	UNSAVE_SERIES(newparse.series);
 	return n;
 }
-
+#endif // USE_DO_PARSE_RULE
 
 /***********************************************************************
 **
@@ -931,13 +932,13 @@ void Print_Parse_Index(REBCNT type, REBVAL *rules, REBSER *series, REBCNT index)
 						&& (Parse_Series(val, VAL_BLK_DATA(item), parse->flags, depth+1) == VAL_TAIL(val))
 					) ? index+1 : NOT_FOUND;
 					break;
-
+#ifdef USE_DO_PARSE_RULE
 				case SYM_DO:
 					if (!IS_BLOCK_INPUT(parse)) goto bad_rule;
 					i = Do_Eval_Rule(parse, index, &rules);
 					rulen = 1;
 					break;
-
+#endif
 				default:
 					goto bad_rule;
 				}

src/tests/units/parse-test.r3

@@ -60,5 +60,15 @@ Rebol [
 
 ===end-group===
 
+===start-group=== "DO"
+
+--test-- "issue-2083"
+;@@ https://github.com/Oldes/Rebol-issues/issues/2083
+;@@ https://github.com/Oldes/Rebol-issues/issues/2085
+	--assert error? err: try [parse [1 + 1] [set result do integer!]]
+	--assert err/id = 'parse-rule
+
+===end-group===
+
 
 ~~~end-file~~~