fix: change the type of extra_remarks to a backward list

src/Diagnostic.ml

@@ -1,3 +1,5 @@
+open Bwd
+
 include DiagnosticData
 
 let text s fmt =
@@ -23,7 +25,7 @@ let of_loctext ?(backtrace=Bwd.Emp) ?(extra_remarks=[]) severity message explana
   ; message
   ; explanation
   ; backtrace
-  ; extra_remarks
+  ; extra_remarks = Bwd.of_list extra_remarks
   }
 
 let of_text ?loc ?backtrace ?extra_remarks severity message text : _ t =

src/DiagnosticData.ml

@@ -37,6 +37,6 @@ type 'message t = {
   (** The free-form explanation. *)
   backtrace : backtrace;
   (** The backtrace leading to this diagnostic. *)
-  extra_remarks : loctext list;
-  (** Additional remarks that are relevant to the main message but not part of the backtrace. *)
+  extra_remarks : loctext bwd;
+  (** Additional remarks that are relevant to the main message but not part of the backtrace. It is a backward list so that new remarks can be added to its end easily. *)
 }

src/lsp/LspServer.ml

@@ -1,3 +1,5 @@
+open Bwd
+
 module L = Lsp.Types
 module RPC = Jsonrpc
 module Broadcast = Lsp.Server_notification
@@ -66,7 +68,7 @@ struct
     let code = `String (Message.short_code diag.message) in
     let source = (State.get ()).source in
     let message = Diagnostic.string_of_text diag.explanation.value in
-    let relatedInformation = List.map (render_lsp_related_info uri) diag.extra_remarks in
+    let relatedInformation = Bwd.to_list @@ Bwd.map (render_lsp_related_info uri) diag.extra_remarks in
     Lsp_Diagnostic.create
       ~range
       ~severity

src/tty/Tty.ml

@@ -267,16 +267,16 @@ struct
     let explication =
       let style s x = Explication.{value = x; style = s} in
       let main_span = Option.to_list @@ Option.map (style Style.HighlightedPrimary) loctext.loc in
-      let additional_spans = List.filter_map (fun x -> Option.map (style Style.Additional) x.Span.loc) extra_remarks in
-      E.explicate ~block_splitting_threshold:param.block_splitting_threshold (main_span @ additional_spans)
+      let additional_spans = Bwd.filter_map (fun x -> Option.map (style Style.Additional) x.Span.loc) extra_remarks in
+      E.explicate ~block_splitting_threshold:param.block_splitting_threshold (main_span @ Bwd.to_list additional_spans)
     in
     let line_number_width = Int.max param.line_number_width (line_number_width explication) in
     render_message ~param:{param with line_number_width} ~show_code explication loctext.value
 
   let display_backtrace ~param backtrace =
     let indentation_style = A.fg @@ A.gray 8 in
     let backtrace =
-      Bwd.to_list @@ Bwd.map (display_message ~param ~show_code:false ~extra_remarks:[]) backtrace
+      Bwd.to_list @@ Bwd.map (display_message ~param ~show_code:false ~extra_remarks:Emp) backtrace
     in
     let backtrace =
       I.vcat @@
@@ -309,7 +309,7 @@ struct
     let traces =
       SourceReader.run @@ fun () ->
       Bwd.snoc
-        (backtrace |> Bwd.map (fun msg -> display_message ~param ~show_code:true msg ~extra_remarks:[]))
+        (backtrace |> Bwd.map (fun msg -> display_message ~param ~show_code:true msg ~extra_remarks:Emp))
         (display_message ~param ~show_code:true explanation ~extra_remarks)
       |> Bwd.to_list |> Array.of_list
     in