diff --git a/src/build.ml b/src/build.ml
index 1d69484a..4b5078c9 100644
--- a/src/build.ml
+++ b/src/build.ml
@@ -62,12 +62,16 @@ module Repr = struct
   let get_if_file_exists_exn state =
     match !state with
     | Decided (_, t) -> t
-    | Undecided _ -> code_errorf "Build.get_if_file_exists_exn: got undecided"
+    | Undecided _ ->
+      Exn.code_error "Build.get_if_file_exists_exn: got undecided" []
 
   let get_glob_result_exn state =
     match !state with
     | G_evaluated l -> l
-    | G_unevaluated _ -> code_errorf "Build.get_glob_result_exn: got unevaluated"
+    | G_unevaluated (loc, path, _) ->
+      Exn.code_error "Build.get_glob_result_exn: got unevaluated"
+        [ "loc", Loc.sexp_of_t loc
+        ; "path", Path.sexp_of_t path ]
 end
 include Repr
 let repr t = t
diff --git a/src/build_interpret.ml b/src/build_interpret.ml
index 8ae453d2..7144a23b 100644
--- a/src/build_interpret.ml
+++ b/src/build_interpret.ml
@@ -169,13 +169,19 @@ let targets =
     | Fail _ -> acc
     | If_file_exists (_, state) -> begin
         match !state with
-        | Decided _ -> code_errorf "Build_interpret.targets got decided if_file_exists"
+        | Decided (v, _) ->
+          Exn.code_error "Build_interpret.targets got decided if_file_exists"
+            ["exists", Sexp.To_sexp.bool v]
         | Undecided (a, b) ->
           match loop a [], loop b [] with
           | [], [] -> acc
-          | _ ->
-            code_errorf "Build_interpret.targets: cannot have targets \
-                         under a [if_file_exists]"
+          | a, b ->
+            let targets x = Path.Set.sexp_of_t (Target.paths x) in
+            Exn.code_error "Build_interpret.targets: cannot have targets \
+                            under a [if_file_exists]"
+              [ "targets-a", targets a
+              ; "targets-b", targets b
+              ]
       end
     | Memo m -> loop m.t acc
     | Catch (t, _) -> loop t acc
diff --git a/src/build_system.ml b/src/build_system.ml
index 995c750a..0f5ec198 100644
--- a/src/build_system.ml
+++ b/src/build_system.ml
@@ -407,9 +407,11 @@ let entry_point t ~f =
   (match t.load_dir_stack with
    | [] ->
      ()
-   | _ :: _ ->
-     code_errorf
-       "Build_system.entry_point: called inside the rule generator callback");
+   | stack ->
+     Exn.code_error
+       "Build_system.entry_point: called inside the rule generator callback"
+       ["stack", Sexp.To_sexp.list Path.sexp_of_t stack]
+  );
   f ()
 
 module Target = Build_interpret.Target
diff --git a/src/errors.ml b/src/errors.ml
index 453f3543..d12c1aed 100644
--- a/src/errors.ml
+++ b/src/errors.ml
@@ -12,8 +12,5 @@ let kerrf fmt ~f =
        f s)
     err_ppf fmt
 
-let code_errorf fmt =
-  kerrf fmt ~f:(fun s -> Stdune.Exn.code_error s [])
-
 let die fmt =
   kerrf fmt ~f:(fun s -> raise (Fatal_error s))
diff --git a/src/errors.mli b/src/errors.mli
index cb728d76..d61f0321 100644
--- a/src/errors.mli
+++ b/src/errors.mli
@@ -22,9 +22,6 @@ exception Already_reported
 (** Raise a [Fatal_error] exception *)
 val die : ('a, Format.formatter, unit, 'b) format4 -> 'a
 
-(** Raise a [Code_error] exception *)
-val code_errorf : ('a, Format.formatter, unit, 'b) format4 -> 'a
-
 (**/**)
 (* Referenced in Ansi_color and Report_error *)
 val err_buf : Buffer.t
diff --git a/src/module.ml b/src/module.ml
index b46f85c9..df187f99 100644
--- a/src/module.ml
+++ b/src/module.ml
@@ -31,7 +31,8 @@ module File = struct
 
   let to_ocaml t =
     match t.syntax with
-    | OCaml -> code_errorf "to_ocaml: can only convert reason Files" ()
+    | OCaml -> Exn.code_error "to_ocaml: can only convert reason Files"
+                 ["t.name", Sexp.To_sexp.string t.name]
     | Reason ->
       { syntax = OCaml
       ; name =
@@ -40,7 +41,9 @@ module File = struct
           (match Filename.extension t.name with
            | ".re" -> ".ml"
            | ".rei" -> ".mli"
-           | _ -> code_errorf "to_ocaml: unrecognized extension %s" ext ())
+           | _ -> Exn.code_error "to_ocaml: unrecognized extension"
+                    [ "name", Sexp.To_sexp.string t.name
+                    ; "ext", Sexp.To_sexp.string ext ])
       }
 end
 
diff --git a/src/path.ml b/src/path.ml
index 38dd7911..e3350a4e 100644
--- a/src/path.ml
+++ b/src/path.ml
@@ -78,7 +78,7 @@ module Local = struct
 
   let parent = function
     | "" ->
-      code_errorf "Path.Local.parent called on the root"
+      Exn.code_error "Path.Local.parent called on the root" []
     | t ->
       match String.rindex_from t (String.length t - 1) '/' with
       | exception Not_found -> ""
@@ -86,7 +86,7 @@ module Local = struct
 
   let basename = function
     | "" ->
-      code_errorf "Path.Local.basename called on the root"
+      Exn.code_error "Path.Local.basename called on the root" []
     | t ->
       let len = String.length t in
       match String.rindex_from t (len - 1) '/' with