Fix #21769: Segfault with static foreach on tuple struct

Author: thewilsonator

compiler/src/dmd/statementsem.d

@@ -4636,7 +4636,8 @@ public auto makeTupleForeach(Scope* sc, bool isStatic, bool isDecl, ForeachState
             decls.append(Dsymbol.arraySyntaxCopy(dbody));
         else
         {
-            stmts.push(fs._body.syntaxCopy());
+            if (fs.body)
+                stmts.push(fs._body.syntaxCopy());
             s = new CompoundStatement(loc, stmts);
         }
 

compiler/test/compilable/ice21769.d

@@ -0,0 +1,19 @@
+/*TEST_OUTPUT:
+---
+1
+s
+---
+*/
+struct Tuple(S...)
+{
+    S fields;
+    alias fields this;
+}
+
+void f()
+{
+    enum t = Tuple!(int, string)(1, "s");
+
+    static foreach (a; t)
+        pragma(msg, a);
+}