Index: src/GenPoly/GenPoly.h
===================================================================
--- src/GenPoly/GenPoly.h	(revision 93c10dee6eb516206f8cb00b620e8ee4abfb79f8)
+++ src/GenPoly/GenPoly.h	(revision 82a90d4ccb157e922e69f016ae7e0faf1dd7f346)
@@ -20,10 +20,13 @@
 
 #include "ErasableScopedMap.h"    // for ErasableScopedMap
-#include "AST/Decl.hpp"           // for TypeDecl::Data
+#include "AST/Decl.hpp"           // for AggregateDecl
 #include "AST/Fwd.hpp"            // for ApplicationExpr, BaseInstType, Func...
-#include "AST/Type.hpp"           // for TypeInstType::TypeEnvKey
 #include "SymTab/Mangler.h"       // for Mangler
 #include "SynTree/Declaration.h"  // for TypeDecl::Data, AggregateDecl, Type...
 #include "SynTree/SynTree.h"      // for Visitor Nodes
+
+namespace ast {
+	struct TypeEnvKey;
+}
 
 namespace GenPoly {