diff --git a/node.go b/node.go
index ec58faf..d7b2c99 100644
--- a/node.go
+++ b/node.go
@@ -1658,8 +1658,9 @@ func (this *conversionState) convertArrayLiteralCommon(items []node.Node) (strin
 		if idx == 0 {
 			isMapType = (itm.Key != nil)
 		} else {
-			if isMapType != (itm.Key != nil) {
-				return "", parseErr{itm, fmt.Errorf("Can't represent array and map in a single type")}
+			thisElemIsMapType := (itm.Key != nil)
+			if isMapType != thisElemIsMapType {
+				return "", parseErr{itm, fmt.Errorf("Can't represent array and map in a single type (idx[0].isMap=%v != idx[%d].isMap=%v)", isMapType, idx, thisElemIsMapType)}
 			}
 		}