diff --git a/parser-typechecker/src/Unison/Parser.hs b/parser-typechecker/src/Unison/Parser.hs
index 14e4cffe3..0d57784a0 100644
--- a/parser-typechecker/src/Unison/Parser.hs
+++ b/parser-typechecker/src/Unison/Parser.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE TypeFamilies      #-}
 {-# LANGUAGE ViewPatterns      #-}
+{-# LANGUAGE DeriveAnyClass #-}
 
 module Unison.Parser where
 
@@ -53,6 +54,7 @@ import qualified Unison.Hashable as Hashable
 import Unison.Referent (Referent)
 import Unison.Reference (Reference)
 import Unison.Parser.Ann (Ann(..))
+import Text.Megaparsec.Error (ShowErrorComponent)
 
 debug :: Bool
 debug = False
@@ -125,6 +127,9 @@ data Error v
   | FloatPattern Ann
   deriving (Show, Eq, Ord)
 
+instance (Ord v, Show v) => ShowErrorComponent (Error v) where
+  showErrorComponent e = show e
+
 tokenToPair :: L.Token a -> (Ann, a)
 tokenToPair t = (ann t, L.payload t)
 
diff --git a/parser-typechecker/src/Unison/TermPrinter.hs b/parser-typechecker/src/Unison/TermPrinter.hs
index ddeb27c2c..b8c5bdc51 100644
--- a/parser-typechecker/src/Unison/TermPrinter.hs
+++ b/parser-typechecker/src/Unison/TermPrinter.hs
@@ -87,20 +87,20 @@ data BlockContext
   -- This ABT node is at the top level of a TermParser.block.
   = Block
   | Normal
-  deriving (Eq)
+  deriving (Eq, Show)
 
 data InfixContext
   -- This ABT node is an infix operator being used in infix position.
   = Infix
   | NonInfix
-  deriving (Eq)
+  deriving (Eq, Show)
 
 data DocLiteralContext
   -- We won't try and render this ABT node or anything under it as a [: @Doc literal :]
   = NoDoc
   -- We'll keep checking as we recurse down
   | MaybeDoc
-  deriving (Eq)
+  deriving (Eq, Show)
 
 {- Explanation of precedence handling
 
@@ -238,9 +238,13 @@ pretty0
         pblock tm = let (im', uses) = calcImports im tm
                     in uses $ [pretty0 n (ac 0 Block im' doc) tm]
     App' x (Constructor' DD.UnitRef 0) ->
-      paren (p >= 11) $ (fmt S.DelayForceChar $ l "!") <> pretty0 n (ac 11 Normal im doc) x
-    Delay' x  ->
-      paren (p >= 11) $ (fmt S.DelayForceChar $ l "'") <> pretty0 n (ac 11 Normal im doc) x
+      paren (p >= 11 || isBlock x && p >= 3)  $
+        fmt S.DelayForceChar (l "!")
+        <> pretty0 n (ac (if isBlock x then 0 else 10) Normal im doc) x
+    Delay' x ->
+      paren (p >= 11 || isBlock x && p >= 3) $
+        fmt S.DelayForceChar (l "'")
+        <> pretty0 n (ac (if isBlock x then 0 else 10) Normal im doc) x
     List' xs -> PP.group $
       (fmt S.DelimiterChar $ l "[") <> optSpace
           <> intercalateMap ((fmt S.DelimiterChar $ l ",") <> PP.softbreak <> optSpace <> optSpace)
@@ -421,7 +425,7 @@ pretty0
       _      -> undefined
     ps = join $ [ r a f | (a, f) <- reverse xs ]
     r a f =
-      [ pretty0 n (ac 3 Normal im doc)                          a
+      [ pretty0 n (ac (if isBlock a then 12 else 3) Normal im doc) a
       , pretty0 n (AmbientContext 10 Normal Infix im doc False) f
       ]
 
@@ -1176,6 +1180,15 @@ isDestructuringBind scrutinee [MatchCase pat _ (ABT.AbsN' vs _)]
       Pattern.Unbound _ -> False
 isDestructuringBind _ _ = False
 
+isBlock :: Ord v => Term2 vt at ap v a -> Bool
+isBlock tm =
+  case tm of
+    If' _ _ _ -> True
+    Handle' _ _ -> True
+    Match' _ _ -> True
+    LetBlock _ _ -> True
+    _ -> False
+
 pattern LetBlock bindings body <- (unLetBlock -> Just (bindings, body))
 
 -- Collects nested let/let rec blocks into one minimally nested block.
diff --git a/parser-typechecker/src/Unison/TypeParser.hs b/parser-typechecker/src/Unison/TypeParser.hs
index 6ace791bc..7fc5e2392 100644
--- a/parser-typechecker/src/Unison/TypeParser.hs
+++ b/parser-typechecker/src/Unison/TypeParser.hs
@@ -72,7 +72,7 @@ type2 = do
 effect :: Var v => TypeP v
 effect = do
  es <- effectList
- t <- valueTypeLeaf
+ t <- type2
  pure (Type.effect1 (ann es <> ann t) es t)
 
 effectList :: Var v => TypeP v
diff --git a/parser-typechecker/src/Unison/TypePrinter.hs b/parser-typechecker/src/Unison/TypePrinter.hs
index cb853d16b..c4a9af53d 100644
--- a/parser-typechecker/src/Unison/TypePrinter.hs
+++ b/parser-typechecker/src/Unison/TypePrinter.hs
@@ -109,37 +109,37 @@ prettyRaw n im p tp = go n im p tp
       EffectfulArrows' fst rest ->
         case fst of
           Var' v | Var.name v == "()" ->
-            PP.parenthesizeIf (p >= 10) $
-              fmt S.DelayForceChar "'" <> arrows False True rest
+            PP.parenthesizeIf (p >= 10) $ arrows True True rest
           _ -> PP.parenthesizeIf (p >= 0) $
                  go n im 0 fst <> arrows False False rest
       _ -> "error"
     _ -> "error"
   effects Nothing   = mempty
-  effects (Just es) = PP.group $ (fmt S.AbilityBraces "{") <> PP.commas (go n im 0 <$> es) <> (fmt S.AbilityBraces "}")
+  effects (Just es) = PP.group $ fmt S.AbilityBraces "{" <> PP.commas (go n im 0 <$> es) <> (fmt S.AbilityBraces "}")
+  -- `first`: is this the first argument?
+  -- `mes`: list of effects
   arrow delay first mes =
-    (if first then mempty else PP.softbreak <> (fmt S.TypeOperator "->"))
-      <> (if delay then (if first then (fmt S.DelayForceChar "'") else (fmt S.DelayForceChar " '")) else mempty)
+    (if first then mempty else PP.softbreak <> fmt S.TypeOperator "->")
+      <> (if delay then (if first then fmt S.DelayForceChar "'" else fmt S.DelayForceChar " '") else mempty)
       <> effects mes
-      <> if (isJust mes) || (not delay) && (not first) then " " else mempty
+      <> if isJust mes || not delay && not first then " " else mempty
 
-  arrows delay first [(mes, Ref' DD.UnitRef)] = arrow delay first mes <> (fmt S.Unit "()")
+  arrows delay first [(mes, Ref' DD.UnitRef)] = arrow delay first mes <> fmt S.Unit "()"
   arrows delay first ((mes, Ref' DD.UnitRef) : rest) =
-    arrow delay first mes <> (parenNoGroup delay $ arrows True True rest)
+    arrow delay first mes <> parenNoGroup delay (arrows True True rest)
   arrows delay first ((mes, arg) : rest) =
-    arrow delay first mes
-      <> (  parenNoGroup (delay && (not $ null rest))
-         $  go n im 0 arg
-         <> arrows False False rest
-         )
+    arrow delay first mes <> parenNoGroup
+      (delay && not (null rest))
+      (go n im 0 arg <> arrows False False rest)
+
   arrows False False [] = mempty
   arrows False True  [] = mempty  -- not reachable
   arrows True  _     [] = mempty  -- not reachable
 
-  paren True  s = PP.group $ ( fmt S.Parenthesis "(" ) <> s <> ( fmt S.Parenthesis ")" )
+  paren True  s = PP.group $ fmt S.Parenthesis "(" <> s <> fmt S.Parenthesis ")"
   paren False s = PP.group s
 
-  parenNoGroup True  s = ( fmt S.Parenthesis "(" ) <> s <> ( fmt S.Parenthesis ")" )
+  parenNoGroup True  s = fmt S.Parenthesis "(" <> s <> fmt S.Parenthesis ")"
   parenNoGroup False s = s
 
 fmt :: S.Element r -> Pretty (S.SyntaxText' r) -> Pretty (S.SyntaxText' r)
diff --git a/parser-typechecker/tests/Unison/Test/TermPrinter.hs b/parser-typechecker/tests/Unison/Test/TermPrinter.hs
index 66f21a5b8..e51bc3766 100644
--- a/parser-typechecker/tests/Unison/Test/TermPrinter.hs
+++ b/parser-typechecker/tests/Unison/Test/TermPrinter.hs
@@ -344,13 +344,13 @@ test = scope "termprinter" $ tests
   , tc "!f a"
   , tcDiff "f () a ()" "!(!f a)"
   , tcDiff "f a b ()" "!(f a b)"
-  , tcDiff "!f ()" "!(!f)"
-  , tc "!(!foo)"
+  , tcDiff "!f ()" "!!f"
+  , tcDiff "!(!foo)" "!!foo"
   , tc "'bar"
   , tc "'(bar a b)"
-  , tc "'('bar)"
-  , tc "!('bar)"
-  , tc "'(!foo)"
+  , tcDiff "'('bar)" "''bar"
+  , tcDiff "!('bar)" "!'bar"
+  , tcDiff "'(!foo)" "'!foo"
   , tc "x -> '(y -> 'z)"
   , tc "'(x -> '(y -> z))"
   , tc "(\"a\", 2)"
diff --git a/unison-core/src/Unison/Term.hs b/unison-core/src/Unison/Term.hs
index 765f8b991..77cfd96a6 100644
--- a/unison-core/src/Unison/Term.hs
+++ b/unison-core/src/Unison/Term.hs
@@ -443,7 +443,6 @@ unDelay tm = case ABT.out tm of
     |  Set.notMember v (ABT.freeVars body)
     -> Just body
   _ -> Nothing
-
 pattern LamNamed' v body <- (ABT.out -> ABT.Tm (Lam (ABT.Term _ _ (ABT.Abs v body))))
 pattern LamsNamed' vs body <- (unLams' -> Just (vs, body))
 pattern LamsNamedOpt' vs body <- (unLamsOpt' -> Just (vs, body))
diff --git a/unison-src/transcripts-round-trip/main.md b/unison-src/transcripts-round-trip/main.md
index 0cfd4d50e..803ac946d 100644
--- a/unison-src/transcripts-round-trip/main.md
+++ b/unison-src/transcripts-round-trip/main.md
@@ -114,7 +114,7 @@ Regression test for https://github.com/unisonweb/unison/issues/2392
 
 ```unison:hide
 unique ability Zonk where zonk : Nat
-unique type Foo x y = 
+unique type Foo x y =
 
 foo : Nat -> Foo ('{Zonk} a) ('{Zonk} b) -> Nat
 foo n _ = n
@@ -170,3 +170,45 @@ myDoc = {{ **my text** __my text__ **MY_TEXT** ___MY__TEXT___ ~~MY~TEXT~~ **MY*T
 .> load scratch.u
 ```
 
+## Parenthesized let-block with operator
+
+Regression test for https://github.com/unisonweb/unison/issues/1778
+
+```unison:hide
+
+structural ability base.Abort where
+  abort : a
+
+(|>) : a -> (a ->{e} b) -> {e} b
+a |> f = f a
+
+handler : a -> Request {Abort} a -> a
+handler default = cases
+  { a }        -> a
+  {abort -> _} -> default
+
+Abort.toOptional : '{g, Abort} a -> '{g} Optional a
+Abort.toOptional thunk = '(toOptional! thunk)
+
+Abort.toOptional! : '{g, Abort} a ->{g} (Optional a)
+Abort.toOptional! thunk = toDefault! None '(Some !thunk)
+
+Abort.toDefault! : a -> '{g, Abort} a ->{g} a
+Abort.toDefault! default thunk =
+  h x = Abort.toDefault! (handler default x) thunk
+  handle (thunk ()) with h
+
+x = '(let
+  abort
+  0) |> Abort.toOptional
+```
+
+```ucm
+.> add
+.> edit x base.Abort |> handler Abort.toOptional Abort.toOptional! Abort.toDefault!
+.> undo
+```
+
+``` ucm
+.> load scratch.u
+```
diff --git a/unison-src/transcripts-round-trip/main.output.md b/unison-src/transcripts-round-trip/main.output.md
index cb37d5fd6..31b68ffe0 100644
--- a/unison-src/transcripts-round-trip/main.output.md
+++ b/unison-src/transcripts-round-trip/main.output.md
@@ -34,15 +34,15 @@ x = 1 + 1
   most recent, along with the command that got us there. Try:
   
     `fork 2 .old`             
-    `fork #bt17giel42 .old`   to make an old namespace
+    `fork #m41m2ql36i .old`   to make an old namespace
                               accessible again,
                               
-    `reset-root #bt17giel42`  to reset the root namespace and
+    `reset-root #m41m2ql36i`  to reset the root namespace and
                               its history to that of the
                               specified namespace.
   
-  1. #agadr8gg6g : add
-  2. #bt17giel42 : builtins.mergeio
+  1. #j1vrihj69n : add
+  2. #m41m2ql36i : builtins.mergeio
   3. #sjg2v58vn2 : (initial reflogged namespace)
 
 .> reset-root 2
@@ -116,17 +116,17 @@ Without the above stanza, the `edit` will send the definition to the most recent
   most recent, along with the command that got us there. Try:
   
     `fork 2 .old`             
-    `fork #bt17giel42 .old`   to make an old namespace
+    `fork #m41m2ql36i .old`   to make an old namespace
                               accessible again,
                               
-    `reset-root #bt17giel42`  to reset the root namespace and
+    `reset-root #m41m2ql36i`  to reset the root namespace and
                               its history to that of the
                               specified namespace.
   
-  1. #rhf1s808fb : add
-  2. #bt17giel42 : reset-root #bt17giel42
-  3. #agadr8gg6g : add
-  4. #bt17giel42 : builtins.mergeio
+  1. #sb99mm43ni : add
+  2. #m41m2ql36i : reset-root #m41m2ql36i
+  3. #j1vrihj69n : add
+  4. #m41m2ql36i : builtins.mergeio
   5. #sjg2v58vn2 : (initial reflogged namespace)
 
 .> reset-root 2
@@ -191,19 +191,19 @@ f x = let
   most recent, along with the command that got us there. Try:
   
     `fork 2 .old`             
-    `fork #bt17giel42 .old`   to make an old namespace
+    `fork #m41m2ql36i .old`   to make an old namespace
                               accessible again,
                               
-    `reset-root #bt17giel42`  to reset the root namespace and
+    `reset-root #m41m2ql36i`  to reset the root namespace and
                               its history to that of the
                               specified namespace.
   
-  1. #gj5agagj7s : add
-  2. #bt17giel42 : reset-root #bt17giel42
-  3. #rhf1s808fb : add
-  4. #bt17giel42 : reset-root #bt17giel42
-  5. #agadr8gg6g : add
-  6. #bt17giel42 : builtins.mergeio
+  1. #t22r3l1hsh : add
+  2. #m41m2ql36i : reset-root #m41m2ql36i
+  3. #sb99mm43ni : add
+  4. #m41m2ql36i : reset-root #m41m2ql36i
+  5. #j1vrihj69n : add
+  6. #m41m2ql36i : builtins.mergeio
   7. #sjg2v58vn2 : (initial reflogged namespace)
 
 .> reset-root 2
@@ -273,21 +273,21 @@ h xs = match xs with
   most recent, along with the command that got us there. Try:
   
     `fork 2 .old`             
-    `fork #bt17giel42 .old`   to make an old namespace
+    `fork #m41m2ql36i .old`   to make an old namespace
                               accessible again,
                               
-    `reset-root #bt17giel42`  to reset the root namespace and
+    `reset-root #m41m2ql36i`  to reset the root namespace and
                               its history to that of the
                               specified namespace.
   
-  1. #3igmh2it4p : add
-  2. #bt17giel42 : reset-root #bt17giel42
-  3. #gj5agagj7s : add
-  4. #bt17giel42 : reset-root #bt17giel42
-  5. #rhf1s808fb : add
-  6. #bt17giel42 : reset-root #bt17giel42
-  7. #agadr8gg6g : add
-  8. #bt17giel42 : builtins.mergeio
+  1. #ebh8598vf0 : add
+  2. #m41m2ql36i : reset-root #m41m2ql36i
+  3. #t22r3l1hsh : add
+  4. #m41m2ql36i : reset-root #m41m2ql36i
+  5. #sb99mm43ni : add
+  6. #m41m2ql36i : reset-root #m41m2ql36i
+  7. #j1vrihj69n : add
+  8. #m41m2ql36i : builtins.mergeio
   9. #sjg2v58vn2 : (initial reflogged namespace)
 
 .> reset-root 2
@@ -314,7 +314,7 @@ Regression test for https://github.com/unisonweb/unison/issues/2392
 
 ```unison
 unique ability Zonk where zonk : Nat
-unique type Foo x y = 
+unique type Foo x y =
 
 foo : Nat -> Foo ('{Zonk} a) ('{Zonk} b) -> Nat
 foo n _ = n
@@ -353,23 +353,23 @@ foo n _ = n
   most recent, along with the command that got us there. Try:
   
     `fork 2 .old`             
-    `fork #bt17giel42 .old`   to make an old namespace
+    `fork #m41m2ql36i .old`   to make an old namespace
                               accessible again,
                               
-    `reset-root #bt17giel42`  to reset the root namespace and
+    `reset-root #m41m2ql36i`  to reset the root namespace and
                               its history to that of the
                               specified namespace.
   
-  1.  #jsnoueu9le : add
-  2.  #bt17giel42 : reset-root #bt17giel42
-  3.  #3igmh2it4p : add
-  4.  #bt17giel42 : reset-root #bt17giel42
-  5.  #gj5agagj7s : add
-  6.  #bt17giel42 : reset-root #bt17giel42
-  7.  #rhf1s808fb : add
-  8.  #bt17giel42 : reset-root #bt17giel42
-  9.  #agadr8gg6g : add
-  10. #bt17giel42 : builtins.mergeio
+  1.  #siglm9vcnk : add
+  2.  #m41m2ql36i : reset-root #m41m2ql36i
+  3.  #ebh8598vf0 : add
+  4.  #m41m2ql36i : reset-root #m41m2ql36i
+  5.  #t22r3l1hsh : add
+  6.  #m41m2ql36i : reset-root #m41m2ql36i
+  7.  #sb99mm43ni : add
+  8.  #m41m2ql36i : reset-root #m41m2ql36i
+  9.  #j1vrihj69n : add
+  10. #m41m2ql36i : builtins.mergeio
   11. #sjg2v58vn2 : (initial reflogged namespace)
 
 .> reset-root 2
@@ -432,25 +432,25 @@ foo =
   most recent, along with the command that got us there. Try:
   
     `fork 2 .old`             
-    `fork #bt17giel42 .old`   to make an old namespace
+    `fork #m41m2ql36i .old`   to make an old namespace
                               accessible again,
                               
-    `reset-root #bt17giel42`  to reset the root namespace and
+    `reset-root #m41m2ql36i`  to reset the root namespace and
                               its history to that of the
                               specified namespace.
   
-  1.  #vbmanbqtlh : add
-  2.  #bt17giel42 : reset-root #bt17giel42
-  3.  #jsnoueu9le : add
-  4.  #bt17giel42 : reset-root #bt17giel42
-  5.  #3igmh2it4p : add
-  6.  #bt17giel42 : reset-root #bt17giel42
-  7.  #gj5agagj7s : add
-  8.  #bt17giel42 : reset-root #bt17giel42
-  9.  #rhf1s808fb : add
-  10. #bt17giel42 : reset-root #bt17giel42
-  11. #agadr8gg6g : add
-  12. #bt17giel42 : builtins.mergeio
+  1.  #re8lsbbg6o : add
+  2.  #m41m2ql36i : reset-root #m41m2ql36i
+  3.  #siglm9vcnk : add
+  4.  #m41m2ql36i : reset-root #m41m2ql36i
+  5.  #ebh8598vf0 : add
+  6.  #m41m2ql36i : reset-root #m41m2ql36i
+  7.  #t22r3l1hsh : add
+  8.  #m41m2ql36i : reset-root #m41m2ql36i
+  9.  #sb99mm43ni : add
+  10. #m41m2ql36i : reset-root #m41m2ql36i
+  11. #j1vrihj69n : add
+  12. #m41m2ql36i : builtins.mergeio
   13. #sjg2v58vn2 : (initial reflogged namespace)
 
 .> reset-root 2
@@ -523,3 +523,120 @@ myDoc = {{ **my text** __my text__ **MY_TEXT** ___MY__TEXT___ ~~MY~TEXT~~ **MY*T
       myDoc : Doc2
 
 ```
+## Parenthesized let-block with operator
+
+Regression test for https://github.com/unisonweb/unison/issues/1778
+
+```unison
+structural ability base.Abort where
+  abort : a
+
+(|>) : a -> (a ->{e} b) -> {e} b
+a |> f = f a
+
+handler : a -> Request {Abort} a -> a
+handler default = cases
+  { a }        -> a
+  {abort -> _} -> default
+
+Abort.toOptional : '{g, Abort} a -> '{g} Optional a
+Abort.toOptional thunk = '(toOptional! thunk)
+
+Abort.toOptional! : '{g, Abort} a ->{g} (Optional a)
+Abort.toOptional! thunk = toDefault! None '(Some !thunk)
+
+Abort.toDefault! : a -> '{g, Abort} a ->{g} a
+Abort.toDefault! default thunk =
+  h x = Abort.toDefault! (handler default x) thunk
+  handle (thunk ()) with h
+
+x = '(let
+  abort
+  0) |> Abort.toOptional
+```
+
+```ucm
+.> add
+
+  ⍟ I've added these definitions:
+  
+    structural ability base.Abort
+    Abort.toDefault!  : a -> '{g, Abort} a ->{g} a
+    Abort.toOptional  : '{g, Abort} a -> '{g} Optional a
+    Abort.toOptional! : '{g, Abort} a ->{g} Optional a
+    handler           : a -> Request {Abort} a -> a
+    x                 : 'Optional Nat
+    |>                : a -> (a ->{e} b) ->{e} b
+
+.> edit x base.Abort |> handler Abort.toOptional Abort.toOptional! Abort.toDefault!
+
+  ☝️
+  
+  I added these definitions to the top of
+  /Users/runar/work/unison/scratch.u
+  
+    structural ability base.Abort where abort : {base.Abort} a
+    
+    Abort.toDefault! : a -> '{g, Abort} a ->{g} a
+    Abort.toDefault! default thunk =
+      h x = Abort.toDefault! (handler default x) thunk
+      handle !thunk with h
+    
+    Abort.toOptional : '{g, Abort} a -> '{g} Optional a
+    Abort.toOptional thunk = '(toOptional! thunk)
+    
+    Abort.toOptional! : '{g, Abort} a ->{g} Optional a
+    Abort.toOptional! thunk = toDefault! None '(Some !thunk)
+    
+    handler : a -> Request {Abort} a -> a
+    handler default = cases
+      { a }        -> a
+      {abort -> _} -> default
+    
+    x : 'Optional Nat
+    x =
+      ('let
+        abort
+        0) |> toOptional
+    
+    (|>) : a -> (a ->{e} b) ->{e} b
+    a |> f = f a
+  
+  You can edit them there, then do `update` to replace the
+  definitions currently in this namespace.
+
+.> undo
+
+  Here are the changes I undid
+  
+  Added definitions:
+  
+    1. structural ability base.Abort
+    2. base.Abort.abort  : {#oup50kgmqv} a
+    3. handler           : a -> Request {#oup50kgmqv} a -> a
+    4. Abort.toDefault!  : a -> '{g, #oup50kgmqv} a ->{g} a
+    5. Abort.toOptional  : '{g, #oup50kgmqv} a
+                         -> '{g} Optional a
+    6. Abort.toOptional! : '{g, #oup50kgmqv} a ->{g} Optional a
+    7. x                 : 'Optional Nat
+    8. |>                : a -> (a ->{e} b) ->{e} b
+
+```
+```ucm
+.> load scratch.u
+
+  I found and typechecked these definitions in scratch.u. If you
+  do an `add` or `update`, here's how your codebase would
+  change:
+  
+    ⍟ These new definitions are ok to `add`:
+    
+      structural ability base.Abort
+      Abort.toDefault!  : a -> '{g, Abort} a ->{g} a
+      Abort.toOptional  : '{g, Abort} a -> '{g} Optional a
+      Abort.toOptional! : '{g, Abort} a ->{g} Optional a
+      handler           : a -> Request {Abort} a -> a
+      x                 : 'Optional Nat
+      |>                : a -> (a ->{e} b) ->{e} b
+
+```