diff --git a/source/library/Language/Haskell/Brittany/Internal/Components/OpTree.hs b/source/library/Language/Haskell/Brittany/Internal/Components/OpTree.hs
index 732bea3..5e82f90 100644
--- a/source/library/Language/Haskell/Brittany/Internal/Components/OpTree.hs
+++ b/source/library/Language/Haskell/Brittany/Internal/Components/OpTree.hs
@@ -324,10 +324,19 @@ hardcodedFixity allowUnqualify = \case
   ".>"          -> Just $ Fixity NoSourceText 9 InfixL
   ":?"          -> Just $ Fixity NoSourceText 7 InfixN
   ":-"          -> Just $ Fixity NoSourceText 9 InfixR
-  ".:"          -> Just $ Fixity NoSourceText 9 InfixR
   "$!!"         -> fixity InfixR 0
   "<$!!>"       -> fixity InfixL 4
 
+  -- aeson
+  -- ".=" -> fixity InfixR 8 -- this clashes with lens :(
+  ".?="         -> fixity InfixR 8
+  ".:"          -> fixity InfixL 9
+  ".:!"         -> fixity InfixL 9
+  ".:?"         -> fixity InfixL 9
+  ".!="         -> fixity InfixL 9
+  ".:?="        -> fixity InfixL 9
+  ".:!="        -> fixity InfixL 9
+
   -- lens, not complete!
   "<|"          -> fixity InfixR 5
   "|>"          -> fixity InfixL 5
@@ -345,7 +354,7 @@ hardcodedFixity allowUnqualify = \case
   "**~"         -> fixity InfixR 4
   "||~"         -> fixity InfixR 4
   "&&~"         -> fixity InfixR 4
-  ".="          -> fixity InfixN 4
+  -- ".="          -> fixity InfixN 4 -- this clashes with aeson :(
   "%="          -> fixity InfixN 4
   "?="          -> fixity InfixN 4
   "+="          -> fixity InfixN 4
@@ -396,8 +405,6 @@ hardcodedFixity allowUnqualify = \case
   "==>"         -> fixity InfixR 0
   "=/="         -> fixity InfixN 4
   "==="         -> fixity InfixN 4
-  ".:!"         -> fixity InfixL 9
-  ".:?"         -> fixity InfixL 9
   -- ".:>"       -> fixity _ _
   -- ".:>?"      -> fixity _ _
   "<.>"         -> fixity InfixR 7