[vala/0.40] vala: Use clearer error message for automatic properties in interfaces

[Rico Tzschichholz <ricotz src gnome org>]

commit bec4c2461ad5e7217248c3bb81b57a529b19a544
Author: Vivek Raj <vivekrajr live com>
Date:   Sat Dec 1 17:10:57 2018 +0100

    vala: Use clearer error message for automatic properties in interfaces
    
    Fixes https://gitlab.gnome.org/GNOME/vala/issues/656

 vala/valainterface.vala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/vala/valainterface.vala b/vala/valainterface.vala
index 72d345476..49a25df17 100644
--- a/vala/valainterface.vala
+++ b/vala/valainterface.vala
@@ -102,7 +102,7 @@ public class Vala.Interface : ObjectTypeSymbol {
         */
        public override void add_property (Property prop) {
                if (prop.field != null) {
-                       Report.error (prop.source_reference, "automatic properties are not allowed in 
interfaces");
+                       Report.error (prop.source_reference, "interface properties should be `abstract' or 
have `get' accessor and/or `set' mutator");
 
                        prop.error = true;
                        return;