[CLI] skip anon args for `infer clang ...`

Summary:
`infer clang ...` was not being handled correctly and would error incorrectly.
Small fix before bigger change.

Reviewed By: mbouaziz

Differential Revision: D5036447

fbshipit-source-id: 87fcc40

infer/src/base/CommandLineOption.ml

@@ -600,11 +600,10 @@ let mk_rest_actions ?(parse_mode=InferCommand) ?(in_help=[]) doc ~usage decode_a
                           decode_json = fun ~inferconfig_dir:_ _ -> []} ;
   rest
 
-let mk_subcommand command ?(accept_unknown_args=false) ?deprecated ~long ?(name=long)
+let mk_subcommand command ?on_unknown_arg:(on_unknown=`Reject) ?deprecated ~long ?(name=long)
     ?parse_mode ?in_help command_doc =
   let switch () =
     curr_command := Some command;
-    let on_unknown = if accept_unknown_args then `Add else `Reject in
     anon_arg_action := {!anon_arg_action with on_unknown} in
   ignore(
     mk ?deprecated ~long ~default:() ?parse_mode ?in_help ~meta:""

infer/src/base/CommandLineOption.mli

@@ -189,8 +189,9 @@ val mk_command_doc : title:string -> section:int -> version:string -> date:strin
 (** [mk_subcommand command ~long command_doc] defines the subcommand [command]. A subcommand is
     activated by passing [--long], [name], or any [-key] for [key] in [deprecated] on the command
     line. [name] defaults to [long]. A man page is automatically generated for [command] based on
-    the information in [command_doc]. *)
-val mk_subcommand : command -> ?accept_unknown_args:bool ->
+    the information in [command_doc]. [on_unknown_arg] is the action taken on unknown anonymous
+    arguments; it is `Reject by default. *)
+val mk_subcommand : command -> ?on_unknown_arg:[`Add | `Skip | `Reject] ->
   ?deprecated:string list -> long:string -> ?name:string ->
   ?parse_mode:parse_mode -> ?in_help:(command * string) list -> command_doc -> unit
 

infer/src/base/Config.ml

@@ -415,16 +415,18 @@ let exe_usage =
 let anon_args = CLOpt.mk_anon ()
 
 let () =
-  let command_accepts_unknown_arg =
-    List.mem ~equal:CLOpt.equal_command CLOpt.[Clang; Report] in
+  let on_unknown_arg_from_command (cmd: CLOpt.command) = match cmd with
+    | Clang -> `Skip
+    | Report -> `Add
+    | Analyze | Capture | Compile | ReportDiff | Run -> `Reject in
   let command_deprecated =
     List.Assoc.find ~equal:CLOpt.equal_command CLOpt.[ReportDiff, ["-diff"]] in
   (* make sure we generate doc for all the commands we know about *)
   List.iter CLOpt.all_commands ~f:(fun cmd ->
       let { CommandDoc.long; command_doc } = CommandDoc.data_of_command cmd in
-      let accept_unknown_args = command_accepts_unknown_arg cmd in
+      let on_unknown_arg = on_unknown_arg_from_command cmd in
       let deprecated = command_deprecated cmd in
-      CLOpt.mk_subcommand cmd ~long ~accept_unknown_args ?deprecated command_doc)
+      CLOpt.mk_subcommand cmd ~long ~on_unknown_arg ?deprecated command_doc)
 
 let abs_struct =
   CLOpt.mk_int ~deprecated:["absstruct"] ~long:"abs-struct" ~default:1