FIX: don't allow code evaluation inside struct construction specification

related to: zsx#51

Author: Oldes

src/core/t-struct.c

@@ -236,7 +236,9 @@ static get_scalar(REBSTU *stu,
 		} else {
 			val = Append_Value(ser);
 			get_scalar(stu, field, 0, val);
+#ifdef ALLOW_CODE_EVALUATION_INSIDE_STRUCT_CONSTRUCTION_SPEC 
 			if (IS_WORD(val)) SET_TYPE(val, REB_LIT_WORD);
+#endif
 		}
 	}
 	return ser;
@@ -735,7 +737,8 @@ static REBOOL parse_field_type(struct Struct_Field *field, REBVAL *spec, REBVAL
 				if (IS_END(blk)) {
 					Trap_Types(RE_EXPECT_VAL, REB_STRUCT, REB_END);
 				}
-				else  if (IS_BLOCK(blk)) {
+#ifdef ALLOW_CODE_EVALUATION_INSIDE_STRUCT_CONSTRUCTION_SPEC 
+				else if (IS_BLOCK(blk)) {
 					Reduce_Block(VAL_SERIES(blk), 0, NULL); //result is on stack
 					init = DS_POP;
 					++ blk;
@@ -747,7 +750,9 @@ static REBOOL parse_field_type(struct Struct_Field *field, REBVAL *spec, REBVAL
 					blk = VAL_BLK_SKIP(data, eval_idx);
 					init = DS_POP; //Do_Next saves result on stack
 				}
-
+#else
+				init = blk++;
+#endif
 				if (field->array) {
 					if (IS_INTEGER(init)) { /* interpreted as a C pointer */
 						void *ptr = (void *)VAL_INT64(init);

src/tests/units/struct-test.r3

@@ -43,7 +43,7 @@ Rebol [
 	--assert (mold u64) = "make struct! [a: [uint64!] 0]"
 	--assert (mold f32) = "make struct! [a: [float!] 0.0]"
 	--assert (mold f64) = "make struct! [a: [double!] 0.0]"
-	--assert (mold w)   = "make struct! [a: [word!] 'none]"
+	--assert (mold w)   = "make struct! [a: [word!] none]"
 ===end-group===
 
 
@@ -104,6 +104,12 @@ Rebol [
 		error? e: try [make struct! [ c: [struct! [a [uint8!]]] ]]
 		e/id = 'expect-val
 	]
+--test-- "Don't allow evaluation inside struct construction"
+;@@ https://github.com/zsx/r3/issues/51
+	--assert all [
+		error? e: try [make struct! [ a: [uint8!] probe random 100 ]]
+		e/id = 'invalid-type
+	]
 ===end-group===