diff --git a/CHANGELOG.md b/CHANGELOG.md
index 570331c4a..8b2f96c1b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@
   This switch causes changes in the formatting results in some cases.
 - Changed how to format a data type with a record constructor to follow
   the [Johan Tibell's Haskell Style Guide]. ([#662]).
+- A newline is no longer inserted after a pattern signature ([#663]).
 
 ### Removed
 
@@ -302,6 +303,7 @@ This version is accidentally pushlished, and is the same as 5.3.3.
 [@uhbif19]: https://github.com/uhbif19
 [@toku-sa-n]: https://github.com/toku-sa-n
 
+[#663]: https://github.com/mihaimaruseac/hindent/pull/663
 [#662]: https://github.com/mihaimaruseac/hindent/pull/662
 [#588]: https://github.com/mihaimaruseac/hindent/pull/588
 [#584]: https://github.com/mihaimaruseac/hindent/pull/584
diff --git a/TESTS.md b/TESTS.md
index 46a2c5310..28e14bb97 100644
--- a/TESTS.md
+++ b/TESTS.md
@@ -1289,7 +1289,6 @@ Unidirectional with a pattern type signature
 {-# LANGUAGE PatternSynonyms #-}
 
 pattern Foo :: Int -> Int -> [Int]
-
 pattern Foo x y <- [x, y]
 ```
 
diff --git a/src/HIndent/Pretty.hs b/src/HIndent/Pretty.hs
index fff384a9b..1cde27548 100644
--- a/src/HIndent/Pretty.hs
+++ b/src/HIndent/Pretty.hs
@@ -157,6 +157,7 @@ instance Pretty HsModule where
         (x, Just $ declSeparator $ unLoc x) : addDeclSeparator xs
       declSeparator (SigD _ TypeSig {}) = newline
       declSeparator (SigD _ InlineSig {}) = newline
+      declSeparator (SigD _ PatSynSig {}) = newline
       declSeparator _ = blankline
       declsExist = not . null . hsmodDecls
       prettyImports = importDecls >>= blanklined . fmap outputImportGroup
diff --git a/src/HIndent/Pretty/Types.hs b/src/HIndent/Pretty/Types.hs
index 27e931a30..55fb88121 100644
--- a/src/HIndent/Pretty/Types.hs
+++ b/src/HIndent/Pretty/Types.hs
@@ -121,17 +121,14 @@ data HsSigType' = HsSigType'
 
 -- | `HsSigType'` for instance declarations.
 pattern HsSigTypeInsideInstDecl :: HsSigType GhcPs -> HsSigType'
-
 pattern HsSigTypeInsideInstDecl x = HsSigType' HsTypeForInstDecl HsTypeNoDir x
 
 -- | `HsSigType'` for function declarations; printed horizontally.
 pattern HsSigTypeInsideVerticalFuncSig :: HsSigType GhcPs -> HsSigType'
-
 pattern HsSigTypeInsideVerticalFuncSig x = HsSigType' HsTypeForFuncSig HsTypeVertical x
 
 -- | `HsSigType'` for a top-level function signature.
 pattern HsSigTypeInsideDeclSig :: HsSigType GhcPs -> HsSigType'
-
 pattern HsSigTypeInsideDeclSig x = HsSigType' HsTypeForDeclSig HsTypeNoDir x
 
 -- | A wrapper for `HsType`.
@@ -144,17 +141,14 @@ data HsType' = HsType'
 
 -- | `HsType'` inside a function signature declaration; printed horizontally.
 pattern HsTypeInsideVerticalFuncSig :: HsType GhcPs -> HsType'
-
 pattern HsTypeInsideVerticalFuncSig x = HsType' HsTypeForFuncSig HsTypeVertical x
 
 -- | `HsType'` inside a top-level function signature declaration.
 pattern HsTypeInsideDeclSig :: HsType GhcPs -> HsType'
-
 pattern HsTypeInsideDeclSig x = HsType' HsTypeForDeclSig HsTypeNoDir x
 
 -- | `HsType'` inside a instance signature declaration.
 pattern HsTypeInsideInstDecl :: HsType GhcPs -> HsType'
-
 pattern HsTypeInsideInstDecl x = HsType' HsTypeForInstDecl HsTypeNoDir x
 
 -- | `StmtLR` inside a vertically printed list.