diff --git a/diagrams-haddock.cabal b/diagrams-haddock.cabal
--- a/diagrams-haddock.cabal
+++ b/diagrams-haddock.cabal
@@ -1,5 +1,5 @@
 name:                diagrams-haddock
-version:             0.2.1
+version:             0.2.1.1
 synopsis:            Preprocessor for embedding diagrams in Haddock documentation
 description:         diagrams-haddock is a tool for compiling embedded inline
                      diagrams code in Haddock documentation, for an
diff --git a/tools/diagrams-haddock.hs b/tools/diagrams-haddock.hs
--- a/tools/diagrams-haddock.hs
+++ b/tools/diagrams-haddock.hs
@@ -116,6 +116,9 @@
                               (Just d, _)           -> d
 
                               -- next, look for active hsenv
+                                -- active hsenv with default name
+                              (Nothing, Just "")    -> "dist"
+                                -- active hsenv with custom name
                               (Nothing, Just hsenv) -> "dist_" ++ hsenv
 
                               -- otherwise, default to "dist"