3 files changed, 28 insertions, 10 deletions

diff --git a/libraries/template-haskell/Language/Haskell/TH/Ppr.hs b/libraries/template-haskell/Language/Haskell/TH/Ppr.hs
index 899d27c38f..3f79920a0b 100644
--- a/libraries/template-haskell/Language/Haskell/TH/Ppr.hs
+++ b/libraries/template-haskell/Language/Haskell/TH/Ppr.hs
@@ -66,7 +66,7 @@ instance Ppr Info where
               case mb_d of { Nothing -> empty; Just d -> ppr d }]
 
 ppr_sig :: Name -> Type -> Doc
-ppr_sig v ty = ppr v <+> dcolon <+> ppr ty
+ppr_sig v ty = pprName' Applied v <+> dcolon <+> ppr ty
 
 pprFixity :: Name -> Fixity -> Doc
 pprFixity _ f | f == defaultFixity = empty
@@ -507,20 +507,24 @@ instance Ppr Con where
                          <+> pprBangType st2
 
     ppr (ForallC ns ctxt (GadtC c sts ty))
-        = commaSep c <+> dcolon <+> pprForall ns ctxt <+> pprGadtRHS sts ty
+        = commaSepApplied c <+> dcolon <+> pprForall ns ctxt
+      <+> pprGadtRHS sts ty
 
     ppr (ForallC ns ctxt (RecGadtC c vsts ty))
-        = commaSep c <+> dcolon <+> pprForall ns ctxt
+        = commaSepApplied c <+> dcolon <+> pprForall ns ctxt
       <+> pprRecFields vsts ty
 
     ppr (ForallC ns ctxt con)
         = pprForall ns ctxt <+> ppr con
 
     ppr (GadtC c sts ty)
-        = commaSep c <+> dcolon <+> pprGadtRHS sts ty
+        = commaSepApplied c <+> dcolon <+> pprGadtRHS sts ty
 
     ppr (RecGadtC c vsts ty)
-        = commaSep c <+> dcolon <+> pprRecFields vsts ty
+        = commaSepApplied c <+> dcolon <+> pprRecFields vsts ty
+
+commaSepApplied :: [Name] -> Doc
+commaSepApplied = commaSepWith (pprName' Applied)
 
 pprForall :: [TyVarBndr] -> Cxt -> Doc
 pprForall ns ctxt
@@ -731,7 +735,12 @@ instance Ppr Loc where
 -- Takes a list of printable things and prints them separated by commas followed
 -- by space.
 commaSep :: Ppr a => [a] -> Doc
-commaSep = sep . punctuate comma . map ppr
+commaSep = commaSepWith ppr
+
+-- Takes a list of things and prints them with the given pretty-printing
+-- function, separated by commas followed by space.
+commaSepWith :: (a -> Doc) -> [a] -> Doc
+commaSepWith pprFun = sep . punctuate comma . map pprFun
 
 -- Takes a list of printable things and prints them separated by semicolons
 -- followed by space.
diff --git a/libraries/template-haskell/Language/Haskell/TH/Syntax.hs b/libraries/template-haskell/Language/Haskell/TH/Syntax.hs
index f571d6b16f..a3284c53eb 100644
--- a/libraries/template-haskell/Language/Haskell/TH/Syntax.hs
+++ b/libraries/template-haskell/Language/Haskell/TH/Syntax.hs
@@ -67,7 +67,7 @@ class Monad m => Quasi m where
   qLookupName :: Bool -> String -> m (Maybe Name)
        -- True <=> type namespace, False <=> value namespace
   qReify          :: Name -> m Info
-  qReifyFixity    :: Name -> m Fixity
+  qReifyFixity    :: Name -> m (Maybe Fixity)
   qReifyInstances :: Name -> [Type] -> m [Dec]
        -- Is (n tys) an instance?
        -- Returns list of matching instance Decs
@@ -355,10 +355,13 @@ and to get information about @D@-the-type, use 'lookupTypeName'.
 reify :: Name -> Q Info
 reify v = Q (qReify v)
 
-{- | @reifyFixity nm@ returns the fixity of @nm@. If a fixity value cannot be
-found, 'defaultFixity' is returned.
+{- | @reifyFixity nm@ attempts to find a fixity declaration for @nm@. For
+example, if the function @foo@ has the fixity declaration @infixr 7 foo@, then
+@reifyFixity 'foo@ would return @'Just' ('Fixity' 7 'InfixR')@. If the function
+@bar@ does not have a fixity declaration, then @reifyFixity 'bar@ returns
+'Nothing', so you may assume @bar@ has 'defaultFixity'.
 -}
-reifyFixity :: Name -> Q Fixity
+reifyFixity :: Name -> Q (Maybe Fixity)
 reifyFixity nm = Q (qReifyFixity nm)
 
 {- | @reifyInstances nm tys@ returns a list of visible instances of @nm tys@. That is,
diff --git a/libraries/template-haskell/changelog.md b/libraries/template-haskell/changelog.md
index 9564e95678..1c0919a8a2 100644
--- a/libraries/template-haskell/changelog.md
+++ b/libraries/template-haskell/changelog.md
@@ -37,6 +37,12 @@
   * Add `reifyConStrictness` to query a data constructor's `DecidedStrictness`
     values for its fields (#10697)
 
+  * The `ClassOpI`, `DataConI`, and `VarI` constructors no longer have a
+    `Fixity` field. Instead, all `Fixity` information for a given `Name` is
+    now determined through the `reifyFixity` function, which returns `Just` the
+    fixity if there is an explicit fixity declaration for that `Name`, and
+    `Nothing` otherwise (#10704 and #11345)
+
   * TODO: document API changes and important bugfixes