Improve error message for renamed forms

Don't include the payload in these messages

Signed-off-by: Rudi Grinberg <rudi.grinberg@gmail.com>

src/string_with_vars.ml

@@ -217,8 +217,11 @@ module Var = struct
 
   let sexp_of_t t = Sexp.atom (to_string t)
 
-  let rename t ~new_name =
-    { t with name = new_name }
+  let with_payload t ~payload =
+    { t with payload }
+
+  let with_name t ~name =
+    { t with name }
 
   let is_form t = Option.is_some t.payload
 end

src/string_with_vars.mli

@@ -65,7 +65,9 @@ module Var : sig
 
   val to_string : t -> string
 
-  val rename : t -> new_name:string -> t
+  val with_name : t -> name:string -> t
+
+  val with_payload : t -> payload:string option -> t
 
   val is_form : t -> bool
 end

src/super_context.ml

@@ -233,8 +233,8 @@ end = struct
     let rec expand t ~syntax_version ~var =
       let name = String_with_vars.Var.name var in
       Option.bind (String.Map.find t name) ~f:(fun v ->
-        let what =
-          lazy (sprintf "Variable %s" (String_with_vars.Var.to_string var)) in
+        let what var =
+          sprintf "Variable %s" (String_with_vars.Var.to_string var) in
         match v with
         | No_info v -> Some v
         | Since (v, min_version) ->
@@ -243,23 +243,30 @@ end = struct
           else
             Syntax.Error.since (String_with_vars.Var.loc var)
               Stanza.syntax syntax_version
-              ~what:(Lazy.force what)
+              ~what:(what var)
         | Renamed_in (in_version, new_name) -> begin
             if syntax_version >= in_version then
+              let var =
+                if String_with_vars.Var.is_form var then
+                  String_with_vars.Var.with_payload var ~payload:(Some "..")
+                else
+                  var
+              in
               Syntax.Error.renamed_in (String_with_vars.Var.loc var)
                 Stanza.syntax syntax_version
-                ~what:(Lazy.force what)
-                ~to_:(String_with_vars.Var.(to_string (rename var ~new_name)))
+                ~what:(what var)
+                ~to_:(let open String_with_vars.Var in
+                  to_string (with_name var ~name:new_name))
             else
               expand t ~syntax_version:in_version
-                ~var:(String_with_vars.Var.rename var ~new_name)
+                ~var:(String_with_vars.Var.with_name var ~name:new_name)
           end
         | Deleted_in (v, in_version) ->
           if syntax_version < in_version then
             Some v
           else
             Syntax.Error.deleted_in (String_with_vars.Var.loc var)
-              Stanza.syntax syntax_version ~what:(Lazy.force what))
+              Stanza.syntax syntax_version ~what:(what var))
   end
 end
 

test/blackbox-tests/test-cases/findlib-error/run.t

@@ -3,7 +3,7 @@ We are dropping support for findlib in dune
   $ dune build --root in-dune target.txt
   Entering directory 'in-dune'
   File "dune", line 2, characters 25-37:
-  Error: Variable %{findlib:pkg} was renamed to '%{lib:pkg}' in the 1.0 version of the dune language
+  Error: Variable %{findlib:..} was renamed to '%{lib:..}' in the 1.0 version of the dune language
   [1]
 
 But it must still be available in jbuild files

test/blackbox-tests/test-cases/path-variables/run.t

@@ -9,7 +9,7 @@ In expands to a file name, and registers this as a dependency.
   $ dune build --root dune @test-dep
   Entering directory 'dune'
   File "dune", line 13, characters 17-47:
-  Error: Variable %{path:file-that-does-not-exist} was renamed to '%{dep:file-that-does-not-exist}' in the 1.0 version of the dune language
+  Error: Variable %{path:..} was renamed to '%{dep:..}' in the 1.0 version of the dune language
   [1]
 
 %{path-no-dep:string}