fix issue 9701 - allow UDAs to be attached to enum values

src/denum.d

@@ -568,7 +568,14 @@ extern (C++) final class EnumMember : VarDeclaration
         protection = ed.isAnonymous() ? ed.protection : Prot(PROTpublic);
         linkage = LINKd;
         storage_class = STCmanifest;
-        userAttribDecl = ed.isAnonymous() ? ed.userAttribDecl : null;
+
+        if(ed.isAnonymous())
+        {
+            if(userAttribDecl)
+                userAttribDecl.userAttribDecl = ed.userAttribDecl;
+            else
+                userAttribDecl = ed.userAttribDecl;
+        }
 
         semanticRun = PASSsemantic;
 

src/parse.d

@@ -2977,6 +2977,17 @@ final class Parser : Lexer
 
                 Type type = null;
                 Identifier ident = null;
+                Expressions* udas = null;
+
+                while(token.value == TOKat)
+                {
+                    if(StorageClass stc = parseAttribute(&udas))
+                    {
+                        error("only user defined attributes can appear in enums, not %s", stcToChars(stc));
+                        nextToken();
+                    }
+                }
+
                 Token* tp = peek(&token);
                 if (token.value == TOKidentifier && (tp.value == TOKassign || tp.value == TOKcomma || tp.value == TOKrcurly))
                 {
@@ -3007,6 +3018,8 @@ final class Parser : Lexer
                 }
 
                 auto em = new EnumMember(loc, ident, value, type);
+                if(udas)
+                    em.userAttribDecl = new UserAttributeDeclaration(udas, new Dsymbols());
                 e.members.push(em);
 
                 if (token.value == TOKrcurly)

test/compilable/test9701.d

@@ -0,0 +1,25 @@
+
+import std.meta;
+
+enum Enum
+{
+    withoutUda,
+    @("first") valueWithUda,
+    @("second", "extra", 3) secondValueWithUda,
+}
+
+@("outter")
+enum
+{
+    @("first") anonFirst,
+    anonSecond,
+    @("third") @("extra") anonThird,
+}
+
+static assert(__traits(getAttributes, Enum.withoutUda).length == 0);
+static assert(__traits(getAttributes, Enum.valueWithUda) == AliasSeq!("first"));
+static assert(__traits(getAttributes, Enum.secondValueWithUda) == AliasSeq!("second", "extra", 3));
+
+static assert(__traits(getAttributes, anonFirst) == AliasSeq!("outter", "first"));
+static assert(__traits(getAttributes, anonSecond) == AliasSeq!("outter"));
+static assert(__traits(getAttributes, anonThird) == AliasSeq!("outter", "third", "extra"));

test/fail_compilation/fail9701.d

@@ -0,0 +1,12 @@
+/*
+TEST_OUTPUT
+---
+fail_compilation/fail9701.d(11): Error: only user defined attributes can appear in enums, not @nogc
+fail_compilation/fail9701.d(11): Error: only user defined attributes can appear in enums, not @disable
+---
+*/
+
+enum Enum
+{
+    @("string") @nogc @(117) @disable @("value", 2525) value,
+}