diff --git a/.travis.yml b/.travis.yml
--- a/.travis.yml
+++ b/.travis.yml
@@ -12,7 +12,7 @@
 install:
   - cabal configure -flib-Werror $mode
   - cabal build
-  - cabal install --enable-documentation
+  - cabal install $mode --enable-documentation
 
 script:
   - $script
@@ -27,3 +27,4 @@
 
 env:
   - mode="--enable-tests" script="cabal test --show-details=always"
+
diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,7 @@
+0.9.1
+-----
+* `contravariant 1` support
+
 0.9
 ---
 * `lens 4` support
diff --git a/sparse.cabal b/sparse.cabal
--- a/sparse.cabal
+++ b/sparse.cabal
@@ -1,6 +1,6 @@
 name:          sparse
 category:      Data, Vector
-version:       0.9
+version:       0.9.1
 license:       BSD3
 cabal-version: >= 1.8
 license-file:  LICENSE
@@ -59,14 +59,14 @@
 library
   build-depends:
     base              >= 4     && < 5,
-    contravariant     >= 0.4.2 && < 1,
+    contravariant     >= 1     && < 2,
     deepseq           >= 1.1   && < 1.4,
     hybrid-vectors    >= 0.1   && < 1,
     lens              >= 4     && < 5,
     primitive         >= 0.5   && < 0.6,
-    transformers      >= 0.3   && < 0.4,
+    transformers      >= 0.3   && < 0.5,
     vector            >= 0.10  && < 0.11,
-    vector-algorithms >= 0.5   && < 0.6
+    vector-algorithms >= 0.5   && < 0.7
 
   hs-source-dirs: src
 
@@ -141,7 +141,7 @@
       containers,
       directory      >= 1.0,
       deepseq,
-      doctest        >= 0.9.1,
+      doctest        >= 0.9.10,
       filepath,
       mtl,
       semigroups     >= 0.9,
diff --git a/src/Sparse/Matrix.hs b/src/Sparse/Matrix.hs
--- a/src/Sparse/Matrix.hs
+++ b/src/Sparse/Matrix.hs
@@ -335,7 +335,8 @@
 {-# INLINEABLE multiplyWith #-}
 multiplyWith times make x0 y0 = case compare (size x0) 1 of
   LT -> empty
-  EQ | size y0 == 1 -> hinted $ go11 (lo x0) (head x0) (lo y0) (head y0)
+  EQ | size y0 == 0 -> empty
+     | size y0 == 1 -> hinted $ go11 (lo x0) (head x0) (lo y0) (head y0)
      | otherwise    -> hinted $ go12 (lo x0) (head x0) (lo y0) y0 (hi y0)
   GT -> case compare (size y0) 1 of
       LT -> empty
diff --git a/tests/doctests.hsc b/tests/doctests.hsc
--- a/tests/doctests.hsc
+++ b/tests/doctests.hsc
@@ -54,9 +54,6 @@
 main :: IO ()
 main = withUnicode $ getSources >>= \sources -> doctest $
     "-isrc"
-  : "-idist/build/autogen"
-  : "-optP-include"
-  : "-optPdist/build/autogen/cabal_macros.h"
   : "-hide-all-packages"
   : map ("-package="++) deps ++ sources