diff --git a/infer/src/base/Config.ml b/infer/src/base/Config.ml
index 6ad610d3e..abd228898 100644
--- a/infer/src/base/Config.ml
+++ b/infer/src/base/Config.ml
@@ -1184,7 +1184,14 @@ and () =
     let (_ : string list ref) =
       CLOpt.mk_string_list ?deprecated ~long
         ~f:(fun issue_id ->
-          let issue = IssueType.register_from_string ~id:issue_id Linters in
+          let issue =
+            match IssueType.find_from_string ~id:issue_id with
+            | Some issue ->
+                issue
+            | None ->
+                (* unknown issue type: assume it will be defined in AL *)
+                IssueType.register_from_string ~id:issue_id Linters
+          in
           IssueType.set_enabled issue b ;
           issue_id )
         ?default ~meta:"issue_type"
diff --git a/infer/src/base/IssueType.ml b/infer/src/base/IssueType.ml
index 427256cf1..6c84731d8 100644
--- a/infer/src/base/IssueType.ml
+++ b/infer/src/base/IssueType.ml
@@ -7,6 +7,7 @@
 
 open! IStd
 module F = Format
+module L = Die
 
 (* Make sure we cannot create new issue types other than by calling [register_from_string]. This is because
      we want to keep track of the list of all the issues ever declared. *)
@@ -24,6 +25,8 @@ module Unsafe : sig
 
   val pp : F.formatter -> t -> unit
 
+  val find_from_string : id:string -> t option
+
   val register_from_string :
        ?enabled:bool
     -> ?hum:string
@@ -77,6 +80,8 @@ end = struct
 
   let set_enabled issue b = issue.enabled <- b
 
+  let find_from_string ~id:unique_id = IssueSet.find_rank !all_issues unique_id
+
   (** Avoid creating new issue types. The idea is that there are three types of issue types:
 
       + Statically pre-defined issue types, namely the ones in this module
@@ -90,10 +95,21 @@ end = struct
         of the issue type, eg in AL. *)
   let register_from_string ?(enabled = true) ?hum:hum0 ?doc_url ?linters_def_file ~id:unique_id
       checker =
-    match IssueSet.find_rank !all_issues unique_id with
-    | Some issue ->
-        (* update human-readable string in case it was supplied this time, but keep the previous
-           value of enabled (see doc comment) *)
+    match find_from_string ~id:unique_id with
+    | ((Some
+         ( { unique_id= _ (* we know it has to be the same *)
+           ; checker= checker_old
+           ; enabled= _ (* not touching this one since [Config] will have set it *)
+           ; hum= _ (* mutable field to update *)
+           ; doc_url= _ (* mutable field to update *)
+           ; linters_def_file= _ (* mutable field to update *) } as issue ))[@warning "+9"]) ->
+        (* update fields that were supplied this time around, but keep the previous values of others
+           and assert that the immutable fields are the same (see doc comment) *)
+        if not (Checker.equal checker checker_old) then
+          L.die InternalError
+            "Checker definition for issue \"%s\" doesn't match: found new checker \"%s\" but \
+             checker \"%s\" was already registered for this issue type"
+            unique_id (Checker.get_name checker) (Checker.get_name checker_old) ;
         Option.iter hum0 ~f:(fun hum -> issue.hum <- hum) ;
         if Option.is_some doc_url then issue.doc_url <- doc_url ;
         if Option.is_some linters_def_file then issue.linters_def_file <- linters_def_file ;
diff --git a/infer/src/base/IssueType.mli b/infer/src/base/IssueType.mli
index f2445dfc3..894eebf72 100644
--- a/infer/src/base/IssueType.mli
+++ b/infer/src/base/IssueType.mli
@@ -24,6 +24,9 @@ val all_issues : unit -> t list
 val pp : Format.formatter -> t -> unit
 (** pretty print a localised string *)
 
+val find_from_string : id:string -> t option
+(** return the issue type if it was previously registered *)
+
 val register_from_string :
      ?enabled:bool
   -> ?hum:string