Better handling of error in fix for #1001

Author: jonludlam

src/document/generator.ml

@@ -26,9 +26,7 @@ let tag tag t = O.span ~attr:tag t
 let label t =
   match t with
   | Odoc_model.Lang.TypeExpr.Label s -> tag "label" (O.txt s)
-  | RawOptional _s ->
-      tag "error" (O.txt "Error: RawOptional found during rendering")
-  | Optional s -> tag "optlabel" (O.txt "?" ++ O.txt s)
+  | Optional s | RawOptional s -> tag "optlabel" (O.txt "?" ++ O.txt s)
 
 let type_var tv = tag "type-var" (O.txt tv)
 
@@ -426,7 +424,14 @@ module Make (Syntax : SYNTAX) = struct
           if not needs_parentheses then res else enclose ~l:"(" res ~r:")"
       | Arrow (Some lbl, src, dst) ->
           let res =
-            O.span
+            match lbl with
+            | RawOptional _ ->
+              O.span
+              ((O.box_hv
+               @@ label lbl ++ O.txt ":" ++ tag "error" (O.txt "???")
+                ++ O.txt " " ++ Syntax.Type.arrow))
+                ++ O.sp ++ type_expr dst
+            | _ -> O.span
               ((O.box_hv
                @@ label lbl ++ O.txt ":" ++ O.cut
                   ++ (O.box_hv @@ type_expr ~needs_parentheses:true src))
@@ -1089,7 +1094,13 @@ module Make (Syntax : SYNTAX) = struct
             (type_expr ~needs_parentheses:true src
             ++ O.txt " " ++ Syntax.Type.arrow)
           ++ O.txt " " ++ class_decl dst
-      | Arrow (Some lbl, src, dst) ->
+      | Arrow (Some (RawOptional _ as lbl), _src, dst) ->
+          O.span
+          ((O.box_hv
+           @@ label lbl ++ O.txt ":" ++ tag "error" (O.txt "???")
+            ++ O.txt " " ++ Syntax.Type.arrow))
+            ++ O.sp ++ class_decl dst
+      | Arrow (Some lbl , src, dst) ->
           O.span
             (label lbl ++ O.txt ":"
             ++ type_expr ~needs_parentheses:true src