From d24a8859b090911a2a48cbbd7666ff7e448acfc8 Mon Sep 17 00:00:00 2001
From: Paul Backus <snarwin@gmail.com>
Date: Fri, 3 Nov 2023 09:17:37 -0400
Subject: [PATCH] Fix Issue 24224 - __traits(initSymbol) treats
 aggregate-derived enum as base type (#15776)

---
 compiler/src/dmd/traits.d                  | 16 ++++++++++++----
 compiler/test/fail_compilation/fail24224.d | 22 ++++++++++++++++++++++
 2 files changed, 34 insertions(+), 4 deletions(-)
 create mode 100644 compiler/test/fail_compilation/fail24224.d

diff --git a/compiler/src/dmd/traits.d b/compiler/src/dmd/traits.d
index ca2af79dde..7489f99aa9 100644
--- a/compiler/src/dmd/traits.d
+++ b/compiler/src/dmd/traits.d
@@ -1875,16 +1875,24 @@ Expression semanticTraits(TraitsExp e, Scope* sc)
             return dimError(1);
 
         auto o = (*e.args)[0];
-        Type t = isType(o);
-        AggregateDeclaration ad = t ? isAggregate(t) : null;
 
-        // Interfaces don't have an init symbol and hence cause linker errors
-        if (!ad || ad.isInterfaceDeclaration())
+        ErrorExp badArgument()
         {
             error(e.loc, "struct / class type expected as argument to __traits(initSymbol) instead of `%s`", o.toChars());
             return ErrorExp.get();
         }
 
+        Type t = isType(o);
+
+        if (!t || t.isTypeEnum())
+            return badArgument();
+
+        AggregateDeclaration ad = isAggregate(t);
+
+        // Interfaces don't have an init symbol and hence cause linker errors
+        if (!ad || ad.isInterfaceDeclaration())
+            return badArgument();
+
         Declaration d = new SymbolDeclaration(ad.loc, ad);
         d.type = Type.tvoid.arrayOf().constOf();
         d.storage_class |= STC.rvalue;
diff --git a/compiler/test/fail_compilation/fail24224.d b/compiler/test/fail_compilation/fail24224.d
new file mode 100644
index 0000000000..db87f5305d
--- /dev/null
+++ b/compiler/test/fail_compilation/fail24224.d
@@ -0,0 +1,22 @@
+/+
+TEST_OUTPUT:
+---
+fail_compilation/fail24224.d(19): Error: struct / class type expected as argument to __traits(initSymbol) instead of `ES`
+fail_compilation/fail24224.d(20): Error: struct / class type expected as argument to __traits(initSymbol) instead of `EU`
+fail_compilation/fail24224.d(21): Error: struct / class type expected as argument to __traits(initSymbol) instead of `EC`
+---
++/
+struct S {}
+union U {}
+class C {}
+
+enum ES : S { a = S.init }
+enum EU : U { a = U.init }
+enum EC : C { a = C.init }
+
+void test()
+{
+    auto init1 = __traits(initSymbol, ES);
+    auto init2 = __traits(initSymbol, EU);
+    auto init3 = __traits(initSymbol, EC);
+}