diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+### 0.3.1 [2019.02.20]
+* Make the build warning-free under `-Wcompat`.
+
 ## 0.3
 * Update for GHC 8.2
   * Since `typeRep#`, `typeNatTypeRep`, and `typeSymbolTypeRep` are no longer
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -17,6 +17,6 @@
 
 `proxied` is a simple library that exports a function to convert constant functions to ones that take a `proxy` value in the `Data.Proxied`. This is useful for retrofiting typeclasses that have functions that return a constant value for any value of a particular type (but still need to consume some value, since one of the parameterized types must appear in a typeclass function). Often, these functions are given `undefined` as an argument, which might be considered poor design.
 
- `Proxy`, however, does not carry any of the error-throwing risks of `undefined`, so it is much more preferable to take `Proxy` as an argument to a constant function instead of `undefined`. Unfortunately, `Proxy` was included in `base` until GHC 7.8, so many of `base`'s typeclasses still contain constant functions that aren't amenable to passing `Proxy`. `proxied` addresses this issue by providing variants of those typeclass functions that take an explicit `proxy` value.
+ `Proxy`, however, does not carry any of the error-throwing risks of `undefined`, so it is much more preferable to take `Proxy` as an argument to a constant function instead of `undefined`. Unfortunately, `Proxy` wasn't included in `base` until GHC 7.8, so many of `base`'s typeclasses still contain constant functions that aren't amenable to passing `Proxy`. `proxied` addresses this issue by providing variants of those typeclass functions that take an explicit `proxy` value.
 
 This library also contains the `Data.Proxyless` module, which works in the opposite direction. That is, one can take functions which take `Proxy` (or `undefined`) as an argument and convert them to functions which take no arguments. This trick relies on the `-XTypeApplications` extension, so it is only available with GHC 8.0 or later.
diff --git a/proxied.cabal b/proxied.cabal
--- a/proxied.cabal
+++ b/proxied.cabal
@@ -1,5 +1,5 @@
 name:                proxied
-version:             0.3
+version:             0.3.1
 synopsis:            Make functions consume Proxy instead of undefined
 description:         @proxied@ is a simple library that exports a function to
                      convert constant functions to ones that take a @proxy@
@@ -15,7 +15,7 @@
                      error-throwing risks of @undefined@, so it is much more
                      preferable to take @Proxy@ as an argument to a constant
                      function instead of @undefined@. Unfortunately, @Proxy@
-                     was included in @base@ until GHC 7.8, so many of @base@'s
+                     wasn't included in @base@ until GHC 7.8, so many of @base@'s
                      typeclasses still contain constant functions that aren't
                      amenable to passing @Proxy@. @proxied@ addresses this
                      issue by providing variants of those typeclass functions
@@ -44,7 +44,9 @@
                    , GHC == 7.8.4
                    , GHC == 7.10.3
                    , GHC == 8.0.2
-                   , GHC == 8.2.1
+                   , GHC == 8.2.2
+                   , GHC == 8.4.4
+                   , GHC == 8.6.3
 extra-source-files:  CHANGELOG.md, README.md
 cabal-version:       >=1.10
 
diff --git a/src/Data/Proxied.hs b/src/Data/Proxied.hs
--- a/src/Data/Proxied.hs
+++ b/src/Data/Proxied.hs
@@ -11,6 +11,10 @@
 {-# LANGUAGE PolyKinds #-}
 #endif
 
+#if __GLASGOW_HASKELL__ >= 800 && __GLASGOW_HASKELL__ < 806
+{-# LANGUAGE TypeInType #-}
+#endif
+
 {-# OPTIONS_GHC -fno-warn-deprecations #-}
 
 {-|
@@ -78,6 +82,9 @@
 
 import Data.Bits (Bits(..))
 import Data.Data hiding (Fixity)
+#if MIN_VERSION_base(4,9,0)
+import Data.Kind (Type)
+#endif
 import Data.Proxy
 
 import Foreign.Storable (Storable(..))
@@ -171,7 +178,11 @@
 -- On @base-4.7@ and later, this is identical to 'typeRep'.
 --
 -- /Since: 0.1/
-typeOfProxied :: forall proxy
+typeOfProxied :: forall
+#if MIN_VERSION_base(4,9,0)
+                        k
+#endif
+                        proxy
 #if MIN_VERSION_base(4,7,0)
                         (a :: k)
 #else
@@ -204,14 +215,20 @@
 -- GHC.Generics
 -------------------------------------------------------------------------------
 
-#define GENERIC_FORALL(t,letter) forall proxy T_TYPE(t) letter f a
+#define GENERIC_FORALL(t,letter) forall K_KINDS proxy T_TYPE(t) letter f a
 
+#if MIN_VERSION_base(4,9,0)
+# define K_KINDS k1 k2
+#else
+# define K_KINDS
+#endif
+
 #if MIN_VERSION_base(4,10,0)
-# define T_TYPE(t) (t :: k1 -> (k2 -> *) -> k2 -> *)
+# define T_TYPE(t) (t :: k1 -> (k2   -> Type) -> k2 -> Type)
 #elif MIN_VERSION_base(4,9,0)
-# define T_TYPE(t) (t :: k1 -> (*  -> *) -> k2 -> *)
+# define T_TYPE(t) (t :: k1 -> (Type -> Type) -> k2 -> Type)
 #else
-# define T_TYPE(t) (t :: *  -> (*  -> *) -> *  -> *)
+# define T_TYPE(t) (t :: *  -> (*    -> *)    -> *  -> *)
 #endif
 
 -- | @'datatypeNameProxied' = 'proxied' 'datatypeName'@
diff --git a/src/Data/Proxyless.hs b/src/Data/Proxyless.hs
--- a/src/Data/Proxyless.hs
+++ b/src/Data/Proxyless.hs
@@ -296,7 +296,7 @@
 theSelDecidedStrictness = selDecidedStrictness @s undefined
 
 -------------------------------------------------------------------------------
--- GHC.Generics
+-- GHC.OverloadedLabels
 -------------------------------------------------------------------------------
 
 -- | In @base-4.10@ and later, this is simply a synonym for 'fromLabel'.