diff --git a/Language/Haskell/TH/ExpandSyns.hs b/Language/Haskell/TH/ExpandSyns.hs
--- a/Language/Haskell/TH/ExpandSyns.hs
+++ b/Language/Haskell/TH/ExpandSyns.hs
@@ -105,7 +105,7 @@
 #else
     report False
 #endif
-      (packagename ++": "++"WARNING: "++msg)
+      (packagename ++": WARNING: "++msg)
 
 
 
@@ -126,6 +126,9 @@
     DataConI {} -> no
     VarI {} -> no
     TyVarI {} -> no
+#if MIN_VERSION_template_haskell(2,12,0)
+    PatSynI {} -> no
+#endif
 
   where
     no = return Nothing
@@ -186,6 +189,11 @@
     go (DefaultSigD {}) = no
 #endif
 
+#if MIN_VERSION_template_haskell(2,12,0)
+    go (PatSynD {}) = no
+    go (PatSynSigD {}) = no
+#endif
+
     no = return Nothing
 
 #if MIN_VERSION_template_haskell(2,4,0)
@@ -312,6 +320,10 @@
       go acc x@WildCardT = passThrough acc x
 #endif
 
+#if MIN_VERSION_template_haskell(2,12,0)
+      go acc x@(UnboxedSumT _) = passThrough acc x
+#endif
+
 class SubstTypeVariable a where
     -- | Capture-free substitution
     subst :: (Name, Type) -> a -> a
@@ -359,6 +371,10 @@
       go (UInfixT t1 nm t2) = UInfixT (go t1) nm (go t2)
       go (ParensT t1) = ParensT (go t1)
       go s@WildCardT = s
+#endif
+
+#if MIN_VERSION_template_haskell(2,12,0)
+      go s@(UnboxedSumT _) = s
 #endif
 
 -- testCapture :: Type
diff --git a/changelog.markdown b/changelog.markdown
--- a/changelog.markdown
+++ b/changelog.markdown
@@ -1,3 +1,7 @@
+## 0.4.3.0
+
+*   Added support for GHC 8.2.1 / template-haskell-2.12 (Thanks to Ryan Scott)
+
 ## 0.4.2.0
 
 *   Eliminated warnings about unrecognized results of 'reify'.
diff --git a/th-expand-syns.cabal b/th-expand-syns.cabal
--- a/th-expand-syns.cabal
+++ b/th-expand-syns.cabal
@@ -1,7 +1,7 @@
 name:                th-expand-syns
-version:             0.4.2.0
+version:             0.4.3.0
 synopsis:            Expands type synonyms in Template Haskell ASTs
-description:         Expands type synonyms in Template Haskell ASTs
+description:         Expands type synonyms in Template Haskell ASTs.
 category:            Template Haskell
 license:             BSD3
 license-file:        LICENSE
@@ -19,14 +19,14 @@
     GHC == 7.8.4
     GHC == 7.10.3
     GHC == 8.0.1
-    GHC == 8.1
+    GHC == 8.2.1
 
 source-repository head
  type: git
  location: git://github.com/DanielSchuessler/th-expand-syns.git
 
 Library
-    build-depends:       base >= 4 && < 5, template-haskell < 2.12, syb, containers
+    build-depends:       base >= 4 && < 5, template-haskell < 2.13, syb, containers
     ghc-options:
     exposed-modules:     Language.Haskell.TH.ExpandSyns