[vala/wip/issue/658: 46/48] Warn if anonymous delegate attribute is ambiguous

[Rico Tzschichholz <ricotz src gnome org>]

commit 0962d9cfce651e31c6662589303f455cd64eb578
Author: Nick Schrader <nick schrader mailbox org>
Date:   Fri Oct 30 01:38:31 2020 -0300

    Warn if anonymous delegate attribute is ambiguous

 vala/valaparser.vala | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)
---
diff --git a/vala/valaparser.vala b/vala/valaparser.vala
index 4a41eb41d..056289961 100644
--- a/vala/valaparser.vala
+++ b/vala/valaparser.vala
@@ -3536,6 +3536,7 @@ public class Vala.Parser : CodeVisitor {
        }
 
        Parameter parse_parameter (Symbol? parent=null, Method? method=null) throws ParseError {
+               var begin_attrs = get_location ();
                var attrs = parse_attributes ();
                var begin = get_location ();
                if (accept (TokenType.ELLIPSIS)) {
@@ -3565,8 +3566,18 @@ public class Vala.Parser : CodeVisitor {
                        pretty_direction = "out";
                }
 
+               string id = parse_identifier ();
+
                var possibly_delegate = type as DelegateType;
                if (possibly_delegate != null && possibly_delegate.delegate_symbol.anonymous) {
+                       if (attrs != null) {
+                               var here = get_location ();
+                               rollback (begin);
+                               Report.warning (get_src (begin_attrs), "Ambiguous attribute: does it belong 
to `%s` or parameter `%s`?"
+                                       .printf (possibly_delegate.to_prototype_string (), id));
+                               rollback (here);
+                       }
+
                        if (pretty_direction != null) {
                                Report.error (get_src (begin), "Anonymous delegates cannot be `" + 
pretty_direction + "` parameters");
                        }
@@ -3580,8 +3591,6 @@ public class Vala.Parser : CodeVisitor {
                        }
                }
 
-               string id = parse_identifier ();
-
                type = parse_inline_array_type (type);
 
                var param = new Parameter (id, type, get_src (begin));