diff --git a/src/Language/Haskell/Assignment.hs b/src/Language/Haskell/Assignment.hs
index af81a1cd9..85d58b346 100644
--- a/src/Language/Haskell/Assignment.hs
+++ b/src/Language/Haskell/Assignment.hs
@@ -78,6 +78,7 @@ type Syntax = '[
   , Syntax.Operator
   , Syntax.OperatorSection
   , Syntax.Pragma
+  , Syntax.PrefixNegation
   , Syntax.QualifiedEntityIdentifier
   , Syntax.QualifiedImportDeclaration
   , Syntax.QuotedName
@@ -245,10 +246,12 @@ expressionChoices = [
                     , newType
                     , operator
                     , operatorSection
+                    , parenthesizedExpression
                     , parenthesizedPattern
                     , parenthesizedTypePattern
                     , pattern
                     , pragma
+                    , prefixNegation
                     , primitiveConstructorIdentifier
                     , primitiveVariableIdentifier
                     , qualifiedConstructorIdentifier
@@ -447,6 +450,9 @@ operatorSection = (makeTerm <$> symbol RightOperatorSection <*> children (Syntax
 packageQualifiedImport :: Assignment
 packageQualifiedImport = makeTerm <$> symbol PackageQualifiedImport <*> (Literal.TextElement <$> source)
 
+parenthesizedExpression :: Assignment
+parenthesizedExpression = symbol ParenthesizedExpression *> children expression
+
 parenthesizedPattern :: Assignment
 parenthesizedPattern = symbol ParenthesizedPattern *> children expressions
 
@@ -459,6 +465,9 @@ pattern = symbol Pattern *> children (expression)
 pragma :: Assignment
 pragma = makeTerm <$> symbol Pragma <*> (Syntax.Pragma <$> source)
 
+prefixNegation :: Assignment
+prefixNegation = makeTerm <$> symbol PrefixNegation <*> children (Syntax.PrefixNegation <$> expression)
+
 primitiveConstructorIdentifier :: Assignment
 primitiveConstructorIdentifier = makeTerm <$> symbol PrimitiveConstructorIdentifier <*> (Syntax.PrimitiveConstructorIdentifier . Name.name <$> source)
 
diff --git a/src/Language/Haskell/Syntax.hs b/src/Language/Haskell/Syntax.hs
index c4b3212c3..6c7cdf661 100644
--- a/src/Language/Haskell/Syntax.hs
+++ b/src/Language/Haskell/Syntax.hs
@@ -524,7 +524,7 @@ instance Show1 ConstructorPattern where liftShowsPrec = genericLiftShowsPrec
 
 instance Evaluatable ConstructorPattern
 
--- e.g. `a <- b` in a Haskell do block
+-- e.g. `a <- b` in a Haskell do block.
 data BindPattern a = BindPattern { bindPatternLeft :: a, bindPatternRight :: a }
   deriving (Declarations1, Diffable, Eq, Foldable, FreeVariables1, Functor, Generic1, Hashable1, Mergeable, Ord, Show, ToJSONFields1, Traversable)
 
@@ -551,3 +551,13 @@ instance Ord1 Lambda where liftCompare = genericLiftCompare
 instance Show1 Lambda where liftShowsPrec = genericLiftShowsPrec
 
 instance Evaluatable Lambda
+
+-- e.g. -1 or (-a) as an expression and not `-` as a variable operator.
+newtype PrefixNegation a = PrefixNegation a
+  deriving (Declarations1, Diffable, Eq, Foldable, FreeVariables1, Functor, Generic1, Hashable1, Mergeable, Ord, Show, ToJSONFields1, Traversable)
+
+instance Eq1 PrefixNegation where liftEq = genericLiftEq
+instance Ord1 PrefixNegation where liftCompare = genericLiftCompare
+instance Show1 PrefixNegation where liftShowsPrec = genericLiftShowsPrec
+
+instance Evaluatable PrefixNegation
diff --git a/test/fixtures/haskell/corpus/algebraic-datatype-declarations.diffA-B.txt b/test/fixtures/haskell/corpus/algebraic-datatype-declarations.diffA-B.txt
index 576c51f44..2eff06678 100644
--- a/test/fixtures/haskell/corpus/algebraic-datatype-declarations.diffA-B.txt
+++ b/test/fixtures/haskell/corpus/algebraic-datatype-declarations.diffA-B.txt
@@ -62,18 +62,6 @@
       ->(TypeConstructorIdentifier) }
         (TypeParameters)
         (Empty))
-      (Constructor
-      { (ConstructorIdentifier)
-      ->(ConstructorIdentifier) }
-        (TypeParameters))
-      (Constructor
-      { (ConstructorIdentifier)
-      ->(ConstructorIdentifier) }
-        (TypeParameters))
-      (Constructor
-      { (ConstructorIdentifier)
-      ->(ConstructorIdentifier) }
-        (TypeParameters))
     {+(Constructor
       {+(ConstructorIdentifier)+}
       {+(TypeParameters)+})+}
@@ -83,6 +71,24 @@
     {+(Constructor
       {+(ConstructorIdentifier)+}
       {+(TypeParameters)+})+}
+    {+(Constructor
+      {+(ConstructorIdentifier)+}
+      {+(TypeParameters)+})+}
+    {+(Constructor
+      {+(ConstructorIdentifier)+}
+      {+(TypeParameters)+})+}
+    {+(Constructor
+      {+(ConstructorIdentifier)+}
+      {+(TypeParameters)+})+}
+    {-(Constructor
+      {-(ConstructorIdentifier)-}
+      {-(TypeParameters)-})-}
+    {-(Constructor
+      {-(ConstructorIdentifier)-}
+      {-(TypeParameters)-})-}
+    {-(Constructor
+      {-(ConstructorIdentifier)-}
+      {-(TypeParameters)-})-}
     {-(Constructor
       {-(ConstructorIdentifier)-}
       {-(TypeParameters)-})-}
diff --git a/test/fixtures/haskell/corpus/algebraic-datatype-declarations.diffB-A.txt b/test/fixtures/haskell/corpus/algebraic-datatype-declarations.diffB-A.txt
index 65afcabce..4c7b58dc6 100644
--- a/test/fixtures/haskell/corpus/algebraic-datatype-declarations.diffB-A.txt
+++ b/test/fixtures/haskell/corpus/algebraic-datatype-declarations.diffB-A.txt
@@ -62,14 +62,15 @@
       ->(TypeConstructorIdentifier) }
         (TypeParameters)
         (Empty))
-      (Constructor
-      { (ConstructorIdentifier)
-      ->(ConstructorIdentifier) }
-        (TypeParameters))
-      (Constructor
-      { (ConstructorIdentifier)
-      ->(ConstructorIdentifier) }
-        (TypeParameters))
+    {+(Constructor
+      {+(ConstructorIdentifier)+}
+      {+(TypeParameters)+})+}
+    {+(Constructor
+      {+(ConstructorIdentifier)+}
+      {+(TypeParameters)+})+}
+    {+(Constructor
+      {+(ConstructorIdentifier)+}
+      {+(TypeParameters)+})+}
       (Constructor
       { (ConstructorIdentifier)
       ->(ConstructorIdentifier) }
@@ -80,9 +81,12 @@
     {+(Constructor
       {+(ConstructorIdentifier)+}
       {+(TypeParameters)+})+}
-    {+(Constructor
-      {+(ConstructorIdentifier)+}
-      {+(TypeParameters)+})+}
+    {-(Constructor
+      {-(ConstructorIdentifier)-}
+      {-(TypeParameters)-})-}
+    {-(Constructor
+      {-(ConstructorIdentifier)-}
+      {-(TypeParameters)-})-}
     {-(Constructor
       {-(ConstructorIdentifier)-}
       {-(TypeParameters)-})-}
diff --git a/test/fixtures/haskell/corpus/expressions.A.hs b/test/fixtures/haskell/corpus/expressions.A.hs
index c27f67cf8..ea9013268 100644
--- a/test/fixtures/haskell/corpus/expressions.A.hs
+++ b/test/fixtures/haskell/corpus/expressions.A.hs
@@ -48,3 +48,9 @@ f = \ (Just a) -> a
 f = \ x -> x : a : xs
 
 f = \ g a b -> g <$> a <*> b
+
+f = (-)
+f = 1 - 1
+f = (-1)
+f = (-a)
+f = -(1)
diff --git a/test/fixtures/haskell/corpus/expressions.B.hs b/test/fixtures/haskell/corpus/expressions.B.hs
index fd2bff77e..e669468d3 100644
--- a/test/fixtures/haskell/corpus/expressions.B.hs
+++ b/test/fixtures/haskell/corpus/expressions.B.hs
@@ -48,3 +48,9 @@ g = \ (Just a) -> a
 g = \ x -> x : a : xs
 
 g = \ g a b -> g <$> a <*> b
+
+g = (-)
+g = 1 - 1
+g = (-1)
+g = (-a)
+g = -(1)
diff --git a/test/fixtures/haskell/corpus/expressions.diffA-B.txt b/test/fixtures/haskell/corpus/expressions.diffA-B.txt
index d41e90860..165e5633c 100644
--- a/test/fixtures/haskell/corpus/expressions.diffA-B.txt
+++ b/test/fixtures/haskell/corpus/expressions.diffA-B.txt
@@ -385,4 +385,45 @@
               (VariableIdentifier)
               (VariableOperator
                 (VariableSymbol))
-              (VariableIdentifier))))))))
+              (VariableIdentifier))))))
+    (Function
+    { (VariableIdentifier)
+    ->(VariableIdentifier) }
+      (Statements
+        (VariableOperator
+          (VariableSymbol))))
+    (Function
+    { (VariableIdentifier)
+    ->(VariableIdentifier) }
+      (Statements
+        (InfixOperatorApp
+          (Integer)
+          (VariableOperator
+            (VariableSymbol))
+          (Integer))))
+  {+(Function
+    {+(VariableIdentifier)+}
+    {+(Statements
+      {+(PrefixNegation
+        {+(Integer)+})+})+})+}
+  {+(Function
+    {+(VariableIdentifier)+}
+    {+(Statements
+      {+(PrefixNegation
+        {+(VariableIdentifier)+})+})+})+}
+    (Function
+    { (VariableIdentifier)
+    ->(VariableIdentifier) }
+      (Statements
+        (PrefixNegation
+          (Integer))))
+  {-(Function
+    {-(VariableIdentifier)-}
+    {-(Statements
+      {-(PrefixNegation
+        {-(VariableIdentifier)-})-})-})-}
+  {-(Function
+    {-(VariableIdentifier)-}
+    {-(Statements
+      {-(PrefixNegation
+        {-(Integer)-})-})-})-}))
diff --git a/test/fixtures/haskell/corpus/expressions.diffB-A.txt b/test/fixtures/haskell/corpus/expressions.diffB-A.txt
index 03eb66329..591ad7c81 100644
--- a/test/fixtures/haskell/corpus/expressions.diffB-A.txt
+++ b/test/fixtures/haskell/corpus/expressions.diffB-A.txt
@@ -327,16 +327,12 @@
             {-(VariableOperator
               {-(VariableSymbol)-})-}
             {-(VariableIdentifier)-})-})-})-}))
-    (Function
-    { (VariableIdentifier)
-    ->(VariableIdentifier) }
-      (Statements
+  {+(Function
+    {+(VariableIdentifier)+}
+    {+(Statements
       {+(QualifiedConstructorIdentifier
         {+(ModuleIdentifier)+}
-        {+(ConstructorIdentifier)+})+}
-      {-(Lambda
-        {-(VariableIdentifier)-}
-        {-(VariableIdentifier)-})-}))
+        {+(ConstructorIdentifier)+})+})+})+}
   {+(Function
     {+(VariableIdentifier)+}
     {+(ConstructorPattern
@@ -397,12 +393,13 @@
             {+(VariableOperator
               {+(VariableSymbol)+})+}
             {+(VariableIdentifier)+})+})+})+})+})+}
-  {+(Function
-    {+(VariableIdentifier)+}
-    {+(Statements
-      {+(Lambda
-        {+(VariableIdentifier)+}
-        {+(VariableIdentifier)+})+})+})+}
+    (Function
+    { (VariableIdentifier)
+    ->(VariableIdentifier) }
+      (Statements
+        (Lambda
+          (VariableIdentifier)
+          (VariableIdentifier))))
     (Function
     { (VariableIdentifier)
     ->(VariableIdentifier) }
@@ -445,4 +442,49 @@
               (VariableIdentifier)
               (VariableOperator
                 (VariableSymbol))
-              (VariableIdentifier))))))))
+              (VariableIdentifier))))))
+    (Function
+    { (VariableIdentifier)
+    ->(VariableIdentifier) }
+      (Statements
+        (VariableOperator
+          (VariableSymbol))))
+    (Function
+    { (VariableIdentifier)
+    ->(VariableIdentifier) }
+      (Statements
+        (InfixOperatorApp
+          (Integer)
+          (VariableOperator
+            (VariableSymbol))
+          (Integer))))
+  {+(Function
+    {+(VariableIdentifier)+}
+    {+(Statements
+      {+(PrefixNegation
+        {+(Integer)+})+})+})+}
+  {+(Function
+    {+(VariableIdentifier)+}
+    {+(Statements
+      {+(PrefixNegation
+        {+(VariableIdentifier)+})+})+})+}
+  {+(Function
+    {+(VariableIdentifier)+}
+    {+(Statements
+      {+(PrefixNegation
+        {+(Integer)+})+})+})+}
+  {-(Function
+    {-(VariableIdentifier)-}
+    {-(Statements
+      {-(PrefixNegation
+        {-(Integer)-})-})-})-}
+  {-(Function
+    {-(VariableIdentifier)-}
+    {-(Statements
+      {-(PrefixNegation
+        {-(VariableIdentifier)-})-})-})-}
+  {-(Function
+    {-(VariableIdentifier)-}
+    {-(Statements
+      {-(PrefixNegation
+        {-(Integer)-})-})-})-}))
diff --git a/test/fixtures/haskell/corpus/expressions.parseA.txt b/test/fixtures/haskell/corpus/expressions.parseA.txt
index ddcc36a9c..d3b8a8dba 100644
--- a/test/fixtures/haskell/corpus/expressions.parseA.txt
+++ b/test/fixtures/haskell/corpus/expressions.parseA.txt
@@ -325,4 +325,32 @@
               (VariableIdentifier)
               (VariableOperator
                 (VariableSymbol))
-              (VariableIdentifier))))))))
+              (VariableIdentifier))))))
+    (Function
+      (VariableIdentifier)
+      (Statements
+        (VariableOperator
+          (VariableSymbol))))
+    (Function
+      (VariableIdentifier)
+      (Statements
+        (InfixOperatorApp
+          (Integer)
+          (VariableOperator
+            (VariableSymbol))
+          (Integer))))
+    (Function
+      (VariableIdentifier)
+      (Statements
+        (PrefixNegation
+          (Integer))))
+    (Function
+      (VariableIdentifier)
+      (Statements
+        (PrefixNegation
+          (VariableIdentifier))))
+    (Function
+      (VariableIdentifier)
+      (Statements
+        (PrefixNegation
+          (Integer))))))
diff --git a/test/fixtures/haskell/corpus/expressions.parseB.txt b/test/fixtures/haskell/corpus/expressions.parseB.txt
index 856ec556b..5f782308f 100644
--- a/test/fixtures/haskell/corpus/expressions.parseB.txt
+++ b/test/fixtures/haskell/corpus/expressions.parseB.txt
@@ -327,4 +327,32 @@
               (VariableIdentifier)
               (VariableOperator
                 (VariableSymbol))
-              (VariableIdentifier))))))))
+              (VariableIdentifier))))))
+    (Function
+      (VariableIdentifier)
+      (Statements
+        (VariableOperator
+          (VariableSymbol))))
+    (Function
+      (VariableIdentifier)
+      (Statements
+        (InfixOperatorApp
+          (Integer)
+          (VariableOperator
+            (VariableSymbol))
+          (Integer))))
+    (Function
+      (VariableIdentifier)
+      (Statements
+        (PrefixNegation
+          (Integer))))
+    (Function
+      (VariableIdentifier)
+      (Statements
+        (PrefixNegation
+          (VariableIdentifier))))
+    (Function
+      (VariableIdentifier)
+      (Statements
+        (PrefixNegation
+          (Integer))))))