diff --git a/generics-sop.cabal b/generics-sop.cabal
--- a/generics-sop.cabal
+++ b/generics-sop.cabal
@@ -1,5 +1,5 @@
 name:                generics-sop
-version:             0.1.0.3
+version:             0.1.0.4
 synopsis:            Generic Programming using True Sums of Products
 description:
   A library to support the definition of generic functions.
diff --git a/src/Generics/SOP.hs b/src/Generics/SOP.hs
--- a/src/Generics/SOP.hs
+++ b/src/Generics/SOP.hs
@@ -296,6 +296,13 @@
   , shape
   , lengthSing
     -- ** Re-exports
+
+-- Workaround for lack of MIN_TOOL_VERSION macro in Cabal 1.18, see:
+-- https://github.com/well-typed/generics-sop/issues/3
+#ifndef MIN_TOOL_VERSION_haddock
+#define MIN_TOOL_VERSION_haddock(x,y,z) 0
+#endif
+
 #if !(defined(__HADDOCK_VERSION__)) || MIN_TOOL_VERSION_haddock(2,14,0)
   , Proxy(..) -- hidden from old Haddock versions, because it triggers an internal error
 #endif