diff --git a/src/DiffSummary.hs b/src/DiffSummary.hs
index 96680ed83..d6892a352 100644
--- a/src/DiffSummary.hs
+++ b/src/DiffSummary.hs
@@ -264,7 +264,7 @@ toTermName source term = case unwrap term of
   S.Continue expr -> toTermName' expr
   S.BlockStatement children -> termNameFromChildren term children
   S.Default children -> termNameFromChildren term children
-  S.FieldDecl id expr -> termNameFromSource id <> (maybe "" (\expr' -> " " <> termNameFromSource expr') expr)
+  S.FieldDecl id expr tag -> termNameFromSource id <> (maybe "" (\expr' -> " " <> termNameFromSource expr') expr) <> (maybe "" ((" " <>) . termNameFromSource) tag)
   where toTermName' = toTermName source
         termNameFromChildren term children = termNameFromRange (unionRangesFrom (range term) (range <$> children))
         termNameFromSource term = termNameFromRange (range term)
diff --git a/src/Language/Go.hs b/src/Language/Go.hs
index ed692b254..d763b25d4 100644
--- a/src/Language/Go.hs
+++ b/src/Language/Go.hs
@@ -143,9 +143,13 @@ termConstructor source sourceSpan name range children _ = case name of
       [ty, values] -> withCategory Struct (S.Struct (Just ty) (toList $ unwrap values))
       rest -> withRanges range Error rest $ S.Error rest
     toFieldDecl = \case
-      [identifier, ty] -> withCategory FieldDecl (S.FieldDecl identifier (Just ty))
-      [identifier] -> withCategory FieldDecl (S.FieldDecl identifier Nothing)
-      rest -> withRanges range Error rest $ S.Error rest
+      rest@[identifier, ty] -> case category (extract ty) of
+        Identifier -> withCategory FieldDecl (S.FieldDecl identifier (Just ty) Nothing)
+        StringLiteral -> withCategory FieldDecl (S.FieldDecl identifier Nothing (Just ty))
+        _ -> withRanges range Error rest (S.Error rest)
+      [identifier] -> withCategory FieldDecl (S.FieldDecl identifier Nothing Nothing)
+      [identifier, ty, tag] -> withCategory FieldDecl (S.FieldDecl identifier (Just ty) (Just tag))
+      rest -> withRanges range Error rest (S.Error rest)
 
     toExpression f = \case
       [expr] -> f expr
diff --git a/src/Renderer/JSON.hs b/src/Renderer/JSON.hs
index b02d47882..9a9726da0 100644
--- a/src/Renderer/JSON.hs
+++ b/src/Renderer/JSON.hs
@@ -149,7 +149,7 @@ syntaxToTermField syntax = case syntax of
   S.ParameterDecl ty field -> [ "type" .= ty ] <> [ "identifier" .= field ]
   S.Default c -> childrenFields c
   S.TypeDecl id ty -> [ "type" .= ty ] <> [ "identifier" .= id ]
-  S.FieldDecl id ty -> [ "type" .= ty ] <> [ "identifier" .= id ]
+  S.FieldDecl id ty tag -> [ "type" .= ty ] <> [ "identifier" .= id ] <> [ "tag" .= tag]
   S.Ty ty -> [ "type" .= ty ]
   S.Send channel expr -> [ "channel" .= channel ] <> [ "expression" .= expr ]
   where childrenFields c = [ "children" .= c ]
diff --git a/src/Syntax.hs b/src/Syntax.hs
index 09e99e6d9..84c1356d8 100644
--- a/src/Syntax.hs
+++ b/src/Syntax.hs
@@ -98,8 +98,8 @@ data Syntax a f
   | ParameterDecl (Maybe f) f
   -- | A type declaration has an identifier and a type.
   | TypeDecl f f
-  -- | A field declaration.
-  | FieldDecl f (Maybe f)
+  -- | A field declaration with an optional type, and an optional tag.
+  | FieldDecl f (Maybe f) (Maybe f)
   -- | A type.
   | Ty f
   -- | A send statement has a channel and an expression in Go.