Ajout de Pervasives.ignore. List.remove -> List.remove_ass*

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@2304 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

38 files changed, 90 insertions, 70 deletions

diff --git a/asmcomp/cmmgen.ml b/asmcomp/cmmgen.ml
index 77c13b4de..3e36407a7 100644
--- a/asmcomp/cmmgen.ml
+++ b/asmcomp/cmmgen.ml
@@ -483,6 +483,8 @@ let rec transl = function
   (* Primitives *)
   | Uprim(Pidentity, [arg]) ->
       transl arg
+  | Uprim(Pignore, [arg]) ->
+      return_unit(transl arg)
   | Uprim(Pgetglobal id, []) ->
       Cconst_symbol(Ident.name id)
 
diff --git a/asmcomp/selectgen.ml b/asmcomp/selectgen.ml
index f072612ef..7c063087e 100644
--- a/asmcomp/selectgen.ml
+++ b/asmcomp/selectgen.ml
@@ -500,7 +500,7 @@ method emit_expr env exp =
               alloc_state <- None;
               rd
           | Some(ralloc, ofs) ->
-              self#insert_op (Iintop_imm(Iadd, ofs)) ralloc rd;
+              ignore(self#insert_op (Iintop_imm(Iadd, ofs)) ralloc rd);
               alloc_state <- Some(ralloc, ofs + size);
               self#emit_stores env new_args ralloc
                                (Arch.offset_addressing header_addressing ofs);
@@ -512,7 +512,7 @@ method emit_expr env exp =
           self#insert_op op r1 rd
       end        
   | Csequence(e1, e2) ->
-      let _ = self#emit_expr env e1 in
+      ignore(self#emit_expr env e1);
       self#emit_expr env e2
   | Cifthenelse(econd, eif, eelse) ->
       let (cond, earg) = self#select_condition econd in
@@ -688,7 +688,7 @@ method emit_tail env exp =
       self#insert (Iop Imove) r1 rd;
       self#insert Iraise rd [||]
   | Csequence(e1, e2) ->
-      let _ = self#emit_expr env e1 in
+      ignore(self#emit_expr env e1);
       self#emit_tail env e2
   | Cifthenelse(econd, eif, eelse) ->
       let (cond, earg) = self#select_condition econd in
diff --git a/bytecomp/bytegen.ml b/bytecomp/bytegen.ml
index 9ecf54d9f..0502aa15d 100644
--- a/bytecomp/bytegen.ml
+++ b/bytecomp/bytegen.ml
@@ -336,6 +336,8 @@ let rec comp_expr env exp sz cont =
       end
   | Lprim(Pidentity, [arg]) ->
       comp_expr env arg sz cont
+  | Lprim(Pignore, [arg]) ->
+      comp_expr env arg sz (add_const_unit cont)
   | Lprim(Pnot, [arg]) ->
       let newcont =
         match cont with
diff --git a/bytecomp/lambda.ml b/bytecomp/lambda.ml
index 231962121..64b14e3ac 100644
--- a/bytecomp/lambda.ml
+++ b/bytecomp/lambda.ml
@@ -17,6 +17,7 @@ open Asttypes
 
 type primitive =
     Pidentity
+  | Pignore
     (* Globals *)
   | Pgetglobal of Ident.t
   | Psetglobal of Ident.t
diff --git a/bytecomp/lambda.mli b/bytecomp/lambda.mli
index 847543936..5302f228d 100644
--- a/bytecomp/lambda.mli
+++ b/bytecomp/lambda.mli
@@ -17,6 +17,7 @@ open Asttypes
 
 type primitive =
     Pidentity
+  | Pignore
     (* Globals *)
   | Pgetglobal of Ident.t
   | Psetglobal of Ident.t
diff --git a/bytecomp/printlambda.ml b/bytecomp/printlambda.ml
index f8564dc9a..cdf4be787 100644
--- a/bytecomp/printlambda.ml
+++ b/bytecomp/printlambda.ml
@@ -53,6 +53,7 @@ let rec structured_constant = function
 
 let primitive = function
     Pidentity -> print_string "id"
+  | Pignore -> print_string "ignore"
   | Pgetglobal id -> print_string "global "; Ident.print id
   | Psetglobal id -> print_string "setglobal "; Ident.print id
   | Pmakeblock(tag, Immutable) -> print_string "makeblock "; print_int tag
diff --git a/bytecomp/symtable.ml b/bytecomp/symtable.ml
index b712282dc..b64b1fe3b 100644
--- a/bytecomp/symtable.ml
+++ b/bytecomp/symtable.ml
@@ -73,8 +73,7 @@ let slot_for_literal cst =
 let c_prim_table = ref(empty_numtable : string numtable)
 
 let set_prim_table name =
- let _ = enter_numtable c_prim_table name in
- ()
+  ignore(enter_numtable c_prim_table name)
 
 let num_of_prim name =
   try
@@ -85,7 +84,7 @@ let num_of_prim name =
     else raise(Error(Unavailable_primitive name))
 
 let require_primitive name =
-  if name.[0] <> '%' then begin let _ = num_of_prim name in () end
+  if name.[0] <> '%' then ignore(num_of_prim name)
 
 let all_primitives () =
   let prim = Array.create !c_prim_table.num_cnt "" in
diff --git a/bytecomp/translcore.ml b/bytecomp/translcore.ml
index a6c7142c2..15395e210 100644
--- a/bytecomp/translcore.ml
+++ b/bytecomp/translcore.ml
@@ -85,6 +85,7 @@ let comparisons_table = create_hashtable 11 [
 
 let primitives_table = create_hashtable 31 [
   "%identity", Pidentity;
+  "%ignore", Pignore;
   "%field0", Pfield 0;
   "%field1", Pfield 1;
   "%setfield0", Psetfield(0, true);
diff --git a/byterun/callback.c b/byterun/callback.c
index f8535caab..1e7883551 100644
--- a/byterun/callback.c
+++ b/byterun/callback.c
@@ -52,7 +52,6 @@ static void thread_callback(void)
 
 value callbackN_exn(value closure, int narg, value args[])
 {
-  value res;
   int i;
 
   Assert(narg + 4 <= 256);
diff --git a/debugger/command_line.ml b/debugger/command_line.ml
index bd8962d7f..43fcd1b6d 100644
--- a/debugger/command_line.ml
+++ b/debugger/command_line.ml
@@ -215,7 +215,7 @@ let instr_cd lexbuf =
 
 let instr_pwd lexbuf =
   eol lexbuf;
-  let _ = system "/bin/pwd" in ()
+  ignore(system "/bin/pwd")
 
 let instr_dir lexbuf =
   let new_directory = argument_list_eol argument lexbuf in
diff --git a/debugger/debugcom.ml b/debugger/debugcom.ml
index ac8103294..e7a3e5043 100644
--- a/debugger/debugcom.ml
+++ b/debugger/debugcom.ml
@@ -119,7 +119,7 @@ let initial_frame () =
   (stack_pos, pc)
 
 let set_initial_frame () =
- let _ = initial_frame () in ()
+  ignore(initial_frame ())
 
 (* Move up one frame *)
 (* Return stack position and current pc.
diff --git a/debugger/frames.ml b/debugger/frames.ml
index 5f4f92e18..d3a0cae53 100644
--- a/debugger/frames.ml
+++ b/debugger/frames.ml
@@ -114,7 +114,7 @@ let do_backtrace action =
           event := any_event_at_pc pc
         done
       with Exit -> ()
-         | Not_found -> let _ = action None in ()
+         | Not_found -> ignore (action None)
       end;
       set_frame initial_sp
 
diff --git a/debugger/history.ml b/debugger/history.ml
index 22dcd35ab..bef338399 100644
--- a/debugger/history.ml
+++ b/debugger/history.ml
@@ -39,4 +39,4 @@ let previous_time_1 () =
 let rec previous_time n =
   if n = 1
   then previous_time_1()
-  else begin let _ = previous_time_1() in previous_time(n-1) end
+  else begin ignore(previous_time_1()); previous_time(n-1) end
diff --git a/debugger/loadprinter.ml b/debugger/loadprinter.ml
index 72d5f2523..aaf48a259 100644
--- a/debugger/loadprinter.ml
+++ b/debugger/loadprinter.ml
@@ -80,7 +80,7 @@ let loadfile name =
     Dynlink.add_interfaces stdlib_units [Config.standard_library];
     Dynlink.allow_unsafe_modules true
   end;
-  let _ = loadfiles name in ()
+  ignore(loadfiles name)
 
 (* Return the value referred to by a path (as in toplevel/topdirs) *)
 (* Note: evaluation proceeds in the debugger memory space, not in
diff --git a/debugger/program_loading.ml b/debugger/program_loading.ml
index 88b5128c4..9b1528335 100644
--- a/debugger/program_loading.ml
+++ b/debugger/program_loading.ml
@@ -51,8 +51,7 @@ let generic_exec cmdline = function () ->
          match fork () with
            0 -> (* Try to detach the process from the controlling terminal,
                    so that it does not receive SIGINT on ctrl-C. *)
-                begin try let _ = setsid() in () 
-                      with Invalid_argument _ -> () end;
+                begin try ignore(setsid()) with Invalid_argument _ -> () end;
                 execv shell [| shell; "-c"; cmdline() |]
          | _ -> exit 0
        with x ->
diff --git a/debugger/show_source.ml b/debugger/show_source.ml
index 5246e7c44..918e130dd 100644
--- a/debugger/show_source.ml
+++ b/debugger/show_source.ml
@@ -61,7 +61,7 @@ let show_point mdle point before selected =
     begin try
       let buffer = get_buffer mdle in
       let (start, line_number) = line_of_pos buffer point in
-        let _ = print_line buffer line_number start point before in ()
+      ignore(print_line buffer line_number start point before)
     with
       Out_of_range -> (* line_of_pos *)
         prerr_endline "Position out of range."
diff --git a/debugger/symbols.ml b/debugger/symbols.ml
index c2737dd62..8f0c7c35e 100644
--- a/debugger/symbols.ml
+++ b/debugger/symbols.ml
@@ -115,7 +115,7 @@ let event_at_pc pc =
   | _            -> ev
 
 let set_event_at_pc pc =
- try let _ = event_at_pc pc in Debugcom.set_event pc
+ try ignore(event_at_pc pc); Debugcom.set_event pc
  with Not_found -> ()
 
 (* List all events in module *)
diff --git a/debugger/time_travel.ml b/debugger/time_travel.ml
index c5aa1a163..dc84ed7ef 100644
--- a/debugger/time_travel.ml
+++ b/debugger/time_travel.ml
@@ -524,7 +524,7 @@ let finish () =
         raise Toplevel
       end;
       begin
-        try let _ = Symbols.any_event_at_pc pc in ()
+        try ignore(Symbols.any_event_at_pc pc)
         with Not_found ->
                prerr_endline "Calling function has no debugging information.";
                raise Toplevel
diff --git a/otherlibs/dynlink/dynlink.ml b/otherlibs/dynlink/dynlink.ml
index ae6c4e016..0ccf3e8f6 100644
--- a/otherlibs/dynlink/dynlink.ml
+++ b/otherlibs/dynlink/dynlink.ml
@@ -137,7 +137,7 @@ let load_compunit ic file_name compunit =
     raise(Error(Linking_error (file_name, new_error)))
   end;
   begin try
-    let _ = (Meta.reify_bytecode code code_size) () in ()
+    ignore((Meta.reify_bytecode code code_size) ())
   with exn ->
     Symtable.restore_state initial_symtable;
     raise exn
diff --git a/otherlibs/threads/pervasives.ml b/otherlibs/threads/pervasives.ml
index acd08d6ac..861ff0ab9 100644
--- a/otherlibs/threads/pervasives.ml
+++ b/otherlibs/threads/pervasives.ml
@@ -132,6 +132,10 @@ external unsafe_char_of_int : int -> char = "%identity"
 let char_of_int n =
   if n < 0 or n > 255 then invalid_arg "char_of_int" else unsafe_char_of_int n
 
+(* Unit operations *)
+
+external ignore : 'a -> unit = "%ignore"
+
 (* Pair operations *)
 
 external fst : 'a * 'b -> 'a = "%field0"
diff --git a/otherlibs/threads/threadUnix.ml b/otherlibs/threads/threadUnix.ml
index a20bdf876..17ab89bb2 100644
--- a/otherlibs/threads/threadUnix.ml
+++ b/otherlibs/threads/threadUnix.ml
@@ -22,17 +22,17 @@ open Unix
    Make sure we're not preempted just after disabling the timer... *)
 let execv proc args =
   Thread.critical_section := true;
-  let _ = Unix.setitimer ITIMER_VIRTUAL {it_interval = 0.0; it_value = 0.0} in
+  ignore(Unix.setitimer ITIMER_VIRTUAL {it_interval = 0.0; it_value = 0.0});
   Unix.execv proc args
 
 let execve proc args env =
   Thread.critical_section := true;
-  let _ = Unix.setitimer ITIMER_VIRTUAL {it_interval = 0.0; it_value = 0.0} in
+  ignore(Unix.setitimer ITIMER_VIRTUAL {it_interval = 0.0; it_value = 0.0});
   Unix.execve proc args env
 
 let execvp proc args =
   Thread.critical_section := true;
-  let _ = Unix.setitimer ITIMER_VIRTUAL {it_interval = 0.0; it_value = 0.0} in
+  ignore(Unix.setitimer ITIMER_VIRTUAL {it_interval = 0.0; it_value = 0.0});
   Unix.execvp proc args
 
 let wait () =
@@ -126,8 +126,7 @@ let connect s addr =
   with Unix_error((EINPROGRESS | EWOULDBLOCK | EAGAIN), _, _) ->
     Thread.wait_write s;
     (* Check if it really worked *)
-    let _ = Unix.getpeername s in
-    ()
+    ignore(Unix.getpeername s)
 
 let rec recv fd buf ofs len flags =
   Thread.wait_read fd;
@@ -178,6 +177,6 @@ let establish_server server_fun sockaddr =
             close_in inchan;
             close_out outchan;
             exit 0
-    | id -> close s; let _ = waitpid [] id (* Reclaim the son *) in ()
+    | id -> close s; ignore(waitpid [] id) (* Reclaim the son *)
   done
 
diff --git a/stdlib/filename.ml b/stdlib/filename.ml
index f3279c95f..6368b7f3a 100644
--- a/stdlib/filename.ml
+++ b/stdlib/filename.ml
@@ -65,9 +65,7 @@ let wnt_is_implicit n =
   && (String.length n < 3 || String.sub n 0 3 <> "..\\")
 ;;
 
-let contains_colon n =
-  try let _ = String.index n ':' in true
-  with Not_found ->                 false
+let contains_colon n = String.contains n ':'
 ;;
 
 let mac_is_relative n =
diff --git a/stdlib/format.ml b/stdlib/format.ml
index a05156c9c..d2fd62d74 100644
--- a/stdlib/format.ml
+++ b/stdlib/format.ml
@@ -303,7 +303,7 @@ let rec advance_left state =
         (size < 0 &&
          (state.pp_right_total - state.pp_left_total < state.pp_space_left))
         then begin
-         let _ = take_queue state.pp_queue in
+         ignore(take_queue state.pp_queue);
          format_pp_token state (if size < 0 then pp_infinity else size) tok;
          state.pp_left_total <- len + state.pp_left_total;
          advance_left state
diff --git a/stdlib/list.ml b/stdlib/list.ml
index 90cee4303..170b803d6 100644
--- a/stdlib/list.ml
+++ b/stdlib/list.ml
@@ -136,13 +136,13 @@ let rec mem_assq x = function
   | [] -> false
   | (a, b) :: l -> a == x || mem_assq x l
 
-let rec remove x = function
+let rec remove_assoc x = function
   | [] -> []
-  | (a, b as pair) :: l -> if a = x then l else pair :: remove x l
+  | (a, b as pair) :: l -> if a = x then l else pair :: remove_assoc x l
 
-let rec removeq x = function
+let rec remove_assq x = function
   | [] -> []
-  | (a, b as pair) :: l -> if a == x then l else pair :: removeq x l
+  | (a, b as pair) :: l -> if a == x then l else pair :: remove_assq x l
 
 let rec find p = function
   | [] -> raise Not_found
@@ -154,6 +154,8 @@ let find_all p =
   | x :: l -> if p x then find (x :: accu) l else find accu l in
   find []
 
+let filter = find_all
+
 let rec partition p l =
   let rec part yes no = function
   | [] -> (rev yes, rev no)
diff --git a/stdlib/list.mli b/stdlib/list.mli
index cdd92b8c6..fd8fd5049 100644
--- a/stdlib/list.mli
+++ b/stdlib/list.mli
@@ -107,15 +107,17 @@ val find : ('a -> bool) -> 'a list -> 'a
            Raise [Not_found] if there is no value that satisfies [p] in the
            list [l]. *)
 
+val filter : ('a -> bool) -> 'a list -> 'a list
 val find_all : ('a -> bool) -> 'a list -> 'a list
-        (* [find_all p l] returns all the elements of the list [l]
-           that satisfies the predicate [p]. *)
+        (* [filter p l] returns all the elements of the list [l]
+           that satisfies the predicate [p].  [find_all] is another name
+           for [filter]. *)
 
 val partition : ('a -> bool) -> 'a list -> 'a list * 'a list
-        (* [partition p l] returns a pair of lists [(l1, l2)], such
-        that [l1] is the list of all the elements of [l] that
-        satisfy the predicate [p], and [l2] is the list of all the
-        elements of [l] that do not satisfy [p]. *)
+        (* [partition p l] returns a pair of lists [(l1, l2)], where
+           [l1] is the list of all the elements of [l] that
+           satisfy the predicate [p], and [l2] is the list of all the
+           elements of [l] that do not satisfy [p]. *)
 
 (** Association lists *)
 
@@ -134,16 +136,16 @@ val mem_assoc : 'a -> ('a * 'b) list -> bool
         (* Same as [assoc], but simply return true if a binding exists,
            and false if no bindings exist for the given key. *)
 val mem_assq : 'a -> ('a * 'b) list -> bool
-        (* Same as [mem_assoc], but uses physical equality instead of structural
-           equality to compare keys. *)
+        (* Same as [mem_assoc], but uses physical equality instead of
+           structural equality to compare keys. *)
 
-val remove : 'a -> ('a * 'b) list -> ('a * 'b) list
-        (* [remove a l] returns the list of
+val remove_assoc : 'a -> ('a * 'b) list -> ('a * 'b) list
+        (* [remove_assoc a l] returns the list of
            pairs [l] without the first pair with key [a], if any. *)
 
-val removeq : 'a -> ('a * 'b) list -> ('a * 'b) list
-        (* Same as [remove], but uses physical equality instead of structural
-           equality to compare keys. *)
+val remove_assq : 'a -> ('a * 'b) list -> ('a * 'b) list
+        (* Same as [remove_assq], but uses physical equality instead
+           of structural equality to compare keys. *)
 
 (** Lists of pairs *)
 
diff --git a/stdlib/pervasives.ml b/stdlib/pervasives.ml
index 37fbef982..ed24d2236 100644
--- a/stdlib/pervasives.ml
+++ b/stdlib/pervasives.ml
@@ -128,6 +128,10 @@ external unsafe_char_of_int : int -> char = "%identity"
 let char_of_int n =
   if n < 0 or n > 255 then invalid_arg "char_of_int" else unsafe_char_of_int n
 
+(* Unit operations *)
+
+external ignore : 'a -> unit = "%ignore"
+
 (* Pair operations *)
 
 external fst : 'a * 'b -> 'a = "%field0"
@@ -264,12 +268,12 @@ let rec input_line chan =
     raise End_of_file
   else if n > 0 then begin              (* n > 0: newline found in buffer *)
     let res = string_create (n-1) in
-    let _ = unsafe_input chan res 0 (n-1) in
-    let _ = input_char chan in          (* skip the newline *)
+    ignore (unsafe_input chan res 0 (n-1));
+    ignore (input_char chan);           (* skip the newline *)
     res
   end else begin                        (* n < 0: newline not found *)
     let beg = string_create (-n) in
-    let _ = unsafe_input chan beg 0 (-n) in
+    ignore(unsafe_input chan beg 0 (-n));
     try
       beg ^ input_line chan
     with End_of_file ->
diff --git a/stdlib/pervasives.mli b/stdlib/pervasives.mli
index 28041b9c2..49bc3a2b2 100644
--- a/stdlib/pervasives.mli
+++ b/stdlib/pervasives.mli
@@ -302,6 +302,14 @@ val char_of_int : int -> char
            Raise [Invalid_argument "char_of_int"] if the argument is
            outside the range 0--255. *)
 
+(*** Unit operations *)
+
+external ignore : 'a -> unit = "%ignore"
+        (* Discard the value of its argument and return [()].
+           For instance, [ignore(f x)] discards the result of
+           the side-effecting function [f].  It is equivalent to
+           [f x; ()], except that no warning is generated. *)
+
 (*** String conversion functions *)
 
 val string_of_bool : bool -> string
diff --git a/stdlib/stream.ml b/stdlib/stream.ml
index 1a707dec6..8b4dd6841 100644
--- a/stdlib/stream.ml
+++ b/stdlib/stream.ml
@@ -120,7 +120,7 @@ let empty s =
 let iter f strm =
   let rec do_rec () =
     match peek strm with
-      Some a -> junk strm; let _ = f a in do_rec ()
+      Some a -> junk strm; ignore(f a); do_rec ()
     | None -> ()
   in
   do_rec ()
diff --git a/stdlib/string.ml b/stdlib/string.ml
index ca32cc6e2..e07fd4b60 100644
--- a/stdlib/string.ml
+++ b/stdlib/string.ml
@@ -159,10 +159,10 @@ let rindex_from s i c =
 
 let contains_from s i c =
   if i < 0 || i >= length s then invalid_arg "String.contains_from" else
-  try let _ = index_rec s (length s) i c in true with Not_found -> false;;
+  try ignore(index_rec s (length s) i c); true with Not_found -> false;;
 
 let rcontains_from s i c =
   if i < 0 || i >= length s then invalid_arg "String.rcontains_from" else
-  try let _ = rindex_rec s i c in true with Not_found -> false;;
+  try ignore(rindex_rec s i c); true with Not_found -> false;;
 
 let contains s c = s <> "" && contains_from s 0 c;;
diff --git a/stdlib/sys.ml b/stdlib/sys.ml
index 23293a153..4bfc0c236 100644
--- a/stdlib/sys.ml
+++ b/stdlib/sys.ml
@@ -40,8 +40,7 @@ type signal_behavior =
 external signal: int -> signal_behavior -> signal_behavior
         = "install_signal_handler"
 
-let set_signal sig_num sig_beh =
-  let _ = signal sig_num sig_beh in ()
+let set_signal sig_num sig_beh = ignore(signal sig_num sig_beh)
 
 let sigabrt = -1
 let sigalrm = -2
diff --git a/toplevel/topdirs.ml b/toplevel/topdirs.ml
index 57ea80430..3437f6897 100644
--- a/toplevel/topdirs.ml
+++ b/toplevel/topdirs.ml
@@ -68,7 +68,7 @@ let load_compunit ic filename compunit =
   Symtable.patch_object code compunit.cu_reloc;
   Symtable.update_global_table();
   begin try
-    let _ = (Meta.reify_bytecode code code_size) () in ()
+    ignore((Meta.reify_bytecode code code_size) ())
   with exn ->
     Symtable.restore_state initial_symtable;
     print_exception_outcome exn;
@@ -106,7 +106,7 @@ let _ = Hashtbl.add directive_table "load" (Directive_string dir_load)
 
 (* Load commands from a file *)
 
-let dir_use name = let _ = Toploop.use_file name in ()
+let dir_use name = ignore(Toploop.use_file name)
 
 let _ = Hashtbl.add directive_table "use" (Directive_string dir_use)
 
diff --git a/toplevel/toploop.ml b/toplevel/toploop.ml
index e5619012a..4551f6465 100644
--- a/toplevel/toploop.ml
+++ b/toplevel/toploop.ml
@@ -208,7 +208,7 @@ let use_file name =
     (* Skip initial #! line if any *)
     let buffer = String.create 2 in
     if input ic buffer 0 2 = 2 && buffer = "#!"
-    then let _ = input_line ic in ()
+    then ignore(input_line ic)
     else seek_in ic 0;
     let success =
       protect Location.input_name filename (fun () ->
@@ -272,8 +272,7 @@ let _ =
   Compile.init_path()
 
 let load_ocamlinit () =
-  if Sys.file_exists ".ocamlinit" then let _ = use_silently ".ocamlinit" in ()
-
+  if Sys.file_exists ".ocamlinit" then ignore(use_silently ".ocamlinit")
 
 (* The interactive loop *)
 
@@ -299,7 +298,7 @@ let loop() =
       Location.reset();
       first_line := true;
       let phr = try !parse_toplevel_phrase lb with Exit -> raise PPerror in
-      let _ = execute_phrase true phr in ()
+      ignore(execute_phrase true phr)
     with
       End_of_file -> exit 0
     | Sys.Break ->
diff --git a/typing/ctype.ml b/typing/ctype.ml
index 91692ab6a..48b969906 100644
--- a/typing/ctype.ml
+++ b/typing/ctype.ml
@@ -1268,7 +1268,7 @@ let rec filter_method env name priv ty =
       raise (Unify [])
 
 let check_filter_method env name priv ty =
- let _ = filter_method env name priv ty in ()
+  ignore(filter_method env name priv ty)
 
 let filter_self_method env lab priv meths ty =
   let ty' = filter_method env lab priv ty in
diff --git a/typing/includemod.ml b/typing/includemod.ml
index ab834ef36..5ce2bfe70 100644
--- a/typing/includemod.ml
+++ b/typing/includemod.ml
@@ -289,7 +289,7 @@ and check_modtype_equiv env mty1 mty2 =
 
 let check_modtype_inclusion env mty1 mty2 =
   try
-    let _ = modtypes env Subst.identity mty1 mty2 in ()
+    ignore(modtypes env Subst.identity mty1 mty2)
   with Error reasons ->
     raise Not_found
 
diff --git a/typing/printtyp.ml b/typing/printtyp.ml
index 13bbae353..07af1342e 100644
--- a/typing/printtyp.ml
+++ b/typing/printtyp.ml
@@ -76,10 +76,10 @@ let print_name_of_type t =
   print_string (name_of_type t)
 
 let check_name_of_type t =
-  let _ = name_of_type t in ()
+  ignore(name_of_type t)
 
 let remove_name_of_type t =
-  names := List.removeq t !names
+  names := List.remove_assq t !names
 
 let visited_objects = ref ([] : type_expr list)
 let aliased = ref ([] : type_expr list)
diff --git a/typing/typemod.ml b/typing/typemod.ml
index 4f509ccb8..0794439d9 100644
--- a/typing/typemod.ml
+++ b/typing/typemod.ml
@@ -74,7 +74,7 @@ let merge_constraint initial_env loc sg lid constr =
       when Ident.name id = s ->
         let (path, mty') = type_module_path initial_env loc lid in
         let newmty = Mtype.strengthen env mty' path in
-        let _ = Includemod.modtypes env newmty mty in
+        ignore(Includemod.modtypes env newmty mty);
         Tsig_module(id, newmty) :: rem
     | (Tsig_module(id, mty) :: rem, s :: namelist, _) when Ident.name id = s ->
         let newsg = merge env (extract_sig env loc mty) namelist in
diff --git a/typing/typetexp.ml b/typing/typetexp.ml
index c0a587f04..4520d94c2 100644
--- a/typing/typetexp.ml
+++ b/typing/typetexp.ml
@@ -130,10 +130,11 @@ let rec transl_type env policy styp =
       let args = List.map (transl_type env policy) stl in
       let params = List.map (fun _ -> Ctype.newvar ()) args in
       let cstr = newty (Tconstr(path, params, ref Mnil)) in
-      let _ =
-        try Ctype.expand_head env cstr with Unify trace ->
-          raise (Error(styp.ptyp_loc, Type_mismatch trace))
-      in
+      begin try
+        ignore(Ctype.expand_head env cstr)
+      with Unify trace ->
+        raise (Error(styp.ptyp_loc, Type_mismatch trace))
+      end;
       List.iter2
         (fun (sty, ty) ty' ->
            try unify env ty ty' with Unify trace ->
diff --git a/utils/ccomp.ml b/utils/ccomp.ml
index 70706f90a..d6dc6daf7 100644
--- a/utils/ccomp.ml
+++ b/utils/ccomp.ml
@@ -21,8 +21,7 @@ let command cmdline =
   end;
   Sys.command cmdline
 
-let run_command cmdline =
-  let _ = command cmdline in ()
+let run_command cmdline = ignore(command cmdline)
 
 let compile_file name =
   command