diff --git a/CHANGELOG.md b/CHANGELOG.md
index 13415a011a7..633bc6eca50 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,7 +2,7 @@
 
 #### Big news
 - Frontend, druntime and Phobos are at version [2.108.0+](https://dlang.org/changelog/2.108.0.html). (#4591, #4615, #4619)
-- Support for [LLVM 18](https://releases.llvm.org/18.1.0/docs/ReleaseNotes.html). The prebuilt packages use v18.1.3 (except for Android and macOS arm64). (#4599, #4605, #4607, #4604)
+- Support for [LLVM 18](https://releases.llvm.org/18.1.0/docs/ReleaseNotes.html). The prebuilt packages use v18.1.3 (except for Android and macOS arm64). (#4599, #4605, #4607, #4604, #4622)
 
 #### Platform support
 - Supports LLVM 11 - 18.
diff --git a/dmd/cparse.d b/dmd/cparse.d
index d5bf8f9eda8..1d978aeab50 100644
--- a/dmd/cparse.d
+++ b/dmd/cparse.d
@@ -5873,13 +5873,15 @@ final class CParser(AST) : Parser!AST
 
         const(char)* endp = &slice[length - 7];
 
+        AST.Dsymbols newSymbols;
+
         size_t[void*] defineTab;    // hash table of #define's turned into Symbol's
-                                    // indexed by Identifier, returns index into symbols[]
+                                    // indexed by Identifier, returns index into newSymbols[]
                                     // The memory for this is leaked
 
-        void addVar(AST.Dsymbol s)
+        void addSym(AST.Dsymbol s)
         {
-            //printf("addVar() %s\n", s.toChars());
+            //printf("addSym() %s\n", s.toChars());
             if (auto v = s.isVarDeclaration())
                 v.isCmacro(true);       // mark it as coming from a C #define
             /* If it's already defined, replace the earlier
@@ -5887,13 +5889,22 @@ final class CParser(AST) : Parser!AST
              */
             if (size_t* pd = cast(void*)s.ident in defineTab)
             {
-                //printf("replacing %s\n", v.toChars());
-                (*symbols)[*pd] = s;
+                //printf("replacing %s\n", s.toChars());
+                newSymbols[*pd] = s;
                 return;
             }
-            assert(symbols, "symbols is null");
-            defineTab[cast(void*)s.ident] = symbols.length;
-            symbols.push(s);
+            defineTab[cast(void*)s.ident] = newSymbols.length;
+            newSymbols.push(s);
+        }
+
+        void removeSym(Identifier ident)
+        {
+            //printf("removeSym() %s\n", ident.toChars());
+            if (size_t* pd = cast(void*)ident in defineTab)
+            {
+                //printf("removing %s\n", ident.toChars());
+                newSymbols[*pd] = null;
+            }
         }
 
         while (p < endp)
@@ -5937,7 +5948,7 @@ final class CParser(AST) : Parser!AST
                                  */
                                 AST.Expression e = new AST.IntegerExp(scanloc, intvalue, t);
                                 auto v = new AST.VarDeclaration(scanloc, t, id, new AST.ExpInitializer(scanloc, e), STC.manifest);
-                                addVar(v);
+                                addSym(v);
                                 ++p;
                                 continue;
                             }
@@ -5960,7 +5971,7 @@ final class CParser(AST) : Parser!AST
                                  */
                                 AST.Expression e = new AST.RealExp(scanloc, floatvalue, t);
                                 auto v = new AST.VarDeclaration(scanloc, t, id, new AST.ExpInitializer(scanloc, e), STC.manifest);
-                                addVar(v);
+                                addSym(v);
                                 ++p;
                                 continue;
                             }
@@ -5978,7 +5989,7 @@ final class CParser(AST) : Parser!AST
                                  */
                                 AST.Expression e = new AST.StringExp(scanloc, str[0 .. len], len, 1, postfix);
                                 auto v = new AST.VarDeclaration(scanloc, null, id, new AST.ExpInitializer(scanloc, e), STC.manifest);
-                                addVar(v);
+                                addSym(v);
                                 ++p;
                                 continue;
                             }
@@ -6014,7 +6025,7 @@ final class CParser(AST) : Parser!AST
                             AST.TemplateParameters* tpl = new AST.TemplateParameters();
                             AST.Expression constraint = null;
                             auto tempdecl = new AST.TemplateDeclaration(exp.loc, id, tpl, constraint, decldefs, false);
-                            addVar(tempdecl);
+                            addSym(tempdecl);
                             ++p;
                             continue;
                         }
@@ -6105,7 +6116,7 @@ final class CParser(AST) : Parser!AST
                             AST.Dsymbols* decldefs = new AST.Dsymbols();
                             decldefs.push(fd);
                             auto tempdecl = new AST.TemplateDeclaration(exp.loc, id, tpl, null, decldefs, false);
-                            addVar(tempdecl);
+                            addSym(tempdecl);
 
                             ++p;
                             continue;
@@ -6116,6 +6127,14 @@ final class CParser(AST) : Parser!AST
                     }
                 }
             }
+            else if (p[0 .. 6] == "#undef")
+            {
+                p += 6;
+                nextToken();
+                //printf("undef %s\n", token.toChars());
+                if (token.value == TOK.identifier)
+                    removeSym(token.ident);
+            }
             // scan to end of line
             while (*p)
                 ++p;
@@ -6123,6 +6142,16 @@ final class CParser(AST) : Parser!AST
             scanloc.linnum = scanloc.linnum + 1;
         }
 
+        if (newSymbols.length)
+        {
+            assert(symbols, "symbols is null");
+            symbols.reserve(newSymbols.length);
+
+            foreach (sym; newSymbols)
+                if (sym) // undefined entries are null
+                    symbols.push(sym);
+        }
+
         scanloc = scanlocSave;
         eSink = save;
         defines = buf;
diff --git a/dmd/traits.d b/dmd/traits.d
index ec89ef5efb2..b3b6b386564 100644
--- a/dmd/traits.d
+++ b/dmd/traits.d
@@ -1245,7 +1245,7 @@ Expression semanticTraits(TraitsExp e, Scope* sc)
             // @@@DEPRECATION 2.100.2
             if (auto td = s.isTemplateDeclaration())
             {
-                if (td.overnext || td.overroot)
+                if (td.overnext)
                 {
                     deprecation(e.loc, "`__traits(getAttributes)` may only be used for individual functions, not the overload set `%s`", td.ident.toChars());
                     deprecationSupplemental(e.loc, "the result of `__traits(getOverloads)` may be used to select the desired function to extract attributes from");
diff --git a/packaging/reggae_version b/packaging/reggae_version
index 1f9498885c1..bf35f0316be 100644
--- a/packaging/reggae_version
+++ b/packaging/reggae_version
@@ -1 +1 @@
-5260790492c465eedde921080952ea34bb14c524
\ No newline at end of file
+9a67d1a1f863c676f30b06ac606b34a792abebdd
\ No newline at end of file
diff --git a/tests/dmd/compilable/test24479.d b/tests/dmd/compilable/test24479.d
new file mode 100644
index 00000000000..7865c1b6074
--- /dev/null
+++ b/tests/dmd/compilable/test24479.d
@@ -0,0 +1,35 @@
+// https://issues.dlang.org/show_bug.cgi?id=24479
+
+/*
+TEST_OUTPUT:
+---
+1
+2
+---
+*/
+
+struct S
+{
+    @1
+    S opBinary(string op: "-")(S rhs) const pure nothrow @nogc
+    {
+        return rhs;
+    }
+    @2
+    S opBinary(string op: "*")(S dur) const pure nothrow @nogc
+    {
+        return dur;
+    }
+}
+
+private enum hasExternalUDA(alias A) = is(A == External) || is(typeof(A) == External);
+
+void foo()
+{
+    static foreach (t; __traits(getOverloads, S, "opBinary", true))
+        static foreach(attr; __traits(getAttributes, t))
+            pragma(msg, attr);
+
+    static assert(__traits(getOverloads, S, "opBinary", true).length == 2);
+    alias A = __traits(getAttributes, __traits(getOverloads, S, "opBinary", true)[1]);
+}
diff --git a/tests/dmd/compilable/test24505.c b/tests/dmd/compilable/test24505.c
new file mode 100644
index 00000000000..9ba16106a81
--- /dev/null
+++ b/tests/dmd/compilable/test24505.c
@@ -0,0 +1,15 @@
+// https://issues.dlang.org/show_bug.cgi?id=24505
+
+// PERMUTE_ARGS:
+
+struct stat { int x; };
+
+void __stat(int x, int y);
+#define stat(x, y) __stat(x, y)
+
+// reversed order:
+#define stat2(x, y) __stat(x, y)
+struct stat2 { int x; };
+
+#undef stat
+#undef stat2