Index: src/Validate/Autogen.cpp
===================================================================
--- src/Validate/Autogen.cpp	(revision 332218007391c23d4a807d5dd8fd971a15d3efb8)
+++ src/Validate/Autogen.cpp	(revision 91715ce19316bcc0ca8afa2dedb8615795eafe46)
@@ -28,4 +28,5 @@
 #include "AST/DeclReplacer.hpp"
 #include "AST/Expr.hpp"
+#include "AST/Inspect.hpp"
 #include "AST/Pass.hpp"
 #include "AST/Stmt.hpp"
@@ -121,5 +122,5 @@
 
 	// Built-ins do not use autogeneration.
-	bool shouldAutogen() const final { return !decl->linkage.is_builtin; }
+	bool shouldAutogen() const final { return !decl->linkage.is_builtin && !structHasFlexibleArray(decl); }
 private:
 	void genFuncBody( ast::FunctionDecl * decl ) final;