CHANGE: do path! behavior made compatible with Rebol2 and Red

resolves: Oldes/Rebol-issues#1881

src/core/n-control.c

@@ -569,7 +569,7 @@ enum {
 ***********************************************************************/
 {
 	REBVAL *value = D_ARG(1);
-	REBINT ret;
+	REBINT ret = R_RET;
 
 	switch (VAL_TYPE(value)) {
 
@@ -599,24 +599,27 @@ enum {
 		ret = R_ARG1;
 		break;
 
-//	case REB_PATH:  ? is it used?
+	case REB_PATH:
+		Do_Path(&value, 0);
+		value = DS_POP; // volatile stack reference
+		if (ANY_FUNC(value)) VAL_SET_OPT(value, OPTS_REVAL);
+		*D_RET = *value;
+		break;
 
 	case REB_WORD:
 	case REB_GET_WORD:
 		*D_RET = *Get_Var(value);
-		ret = R_RET;
 		break;
 
 	case REB_LIT_WORD:
 		*D_RET = *value;
 		SET_TYPE(D_RET, REB_WORD);
-		ret = R_RET;
 		break;
 
 	case REB_LIT_PATH:
 		*D_RET = *value;
 		SET_TYPE(D_RET, REB_PATH);
-		return R_RET;
+		break;
 
 	case REB_ERROR:
 		if (IS_THROW(value)) return R_ARG1;

src/tests/units/evaluation-test.r3

@@ -162,6 +162,20 @@ Rebol [
 
 ===end-group===
 
+===start-group=== "do path!"
+
+	--test-- "do-path-1"
+		o: make object! [a: does ["OK"] b: 23]
+		--assert "OK" == do 'o/a
+		--assert  23  == do 'o/b
+		--assert all [error? e: try [do 'o/x] e/id = 'invalid-path]
+
+	--test-- "do-path-2"
+		b: [["OK"]]
+		--assert ["OK"] == do first [b/1]
+
+===end-group===
+
 ===start-group=== "attempt"
 	--test-- "issue-41"
 		--assert none? attempt [2 / 0] ;@@ https://github.com/Oldes/Rebol-issues/issues/41