diff --git a/polydata.cabal b/polydata.cabal
--- a/polydata.cabal
+++ b/polydata.cabal
@@ -1,5 +1,5 @@
 name:                 polydata
-version:              0.2
+version:              0.3.0.0
 synopsis:             Wrap together data and it's constraints.
 description:
   This package, together with its dependency [polydata-core](https://hackage.haskell.org/package/polydata-core),
@@ -26,7 +26,7 @@
 
 library
   exposed-modules: Data.Poly.Function, Data.Poly.Functor
-  build-depends:        base == 4.9.*, indextype == 0.2.2.*, constraint-manip == 0.1.*, polydata-core == 0.1.*
+  build-depends:        base == 4.9.*, indextype == 0.3.*, constraint-manip == 0.1.*, polydata-core == 0.1.*
   hs-source-dirs:       src
   default-language:     Haskell2010
 
@@ -34,6 +34,6 @@
   type: exitcode-stdio-1.0
   main-is: Tests.hs
   other-modules:  Data.Poly.Function, Data.Poly.Functor
-  build-depends:        base == 4.9.*, indextype == 0.2.2.*, constraint-manip == 0.1.*, polydata-core == 0.1.*, hspec == 2.4.*
+  build-depends:        base == 4.9.*, indextype == 0.3.*, constraint-manip == 0.1.*, polydata-core == 0.1.*, hspec == 2.4.*
   hs-source-dirs:       test, src
   default-language:     Haskell2010
diff --git a/test/Tests.hs b/test/Tests.hs
--- a/test/Tests.hs
+++ b/test/Tests.hs
@@ -21,6 +21,7 @@
 
 import Control.ConstraintManip
 import Data.List (foldl')
+import Data.Type.Equality (type (~~))
 
 import Test.Hspec (hspec, it, shouldBe)
 
@@ -37,7 +38,7 @@
   IndexT 1 t ~ (IndexT 0 (IndexT 0 t)), -- also, the first argument of the function which is the first argument is the same as the second argument of the function
   IsData 1 (IndexT 2 t), -- the third argument is a data type with one variable
   Foldable (GetConstructor1 (IndexT 2 t)), -- the constructor of that third argument is Foldable
-  IndexC 1 0 (IndexT 2 t) ~ IndexT 1 (IndexT 0 t) -- the parameter to the constructor of Foldable is the same as the second argument of the fold function
+  IndexC 1 0 (IndexT 2 t) ~~ IndexT 1 (IndexT 0 t) -- the parameter to the constructor of Foldable is the same as the second argument of the fold function
   )
 
 class (FoldConstraint t) => FoldConstraintC t