ajout warning unused variable

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@6669 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

.depend

@@ -258,6 +258,10 @@ typing/typetexp.cmx: typing/btype.cmx typing/ctype.cmx typing/env.cmx \
     parsing/location.cmx parsing/longident.cmx utils/misc.cmx \
     parsing/parsetree.cmi typing/path.cmx typing/printtyp.cmx utils/tbl.cmx \
     typing/types.cmx utils/warnings.cmx typing/typetexp.cmi 
+typing/unused_var.cmo: parsing/asttypes.cmi parsing/location.cmi \
+    parsing/longident.cmi parsing/parsetree.cmi utils/warnings.cmi 
+typing/unused_var.cmx: parsing/asttypes.cmi parsing/location.cmx \
+    parsing/longident.cmx parsing/parsetree.cmi utils/warnings.cmx 
 bytecomp/bytegen.cmi: bytecomp/instruct.cmi bytecomp/lambda.cmi 
 bytecomp/bytelink.cmi: bytecomp/emitcode.cmi bytecomp/symtable.cmi 
 bytecomp/bytepackager.cmi: typing/ident.cmi 
@@ -401,15 +405,15 @@ bytecomp/translcore.cmx: parsing/asttypes.cmi typing/btype.cmx \
     utils/misc.cmx typing/path.cmx typing/predef.cmx typing/primitive.cmx \
     bytecomp/translobj.cmx typing/typedtree.cmx bytecomp/typeopt.cmx \
     typing/types.cmx bytecomp/translcore.cmi 
-bytecomp/translmod.cmo: parsing/asttypes.cmi utils/config.cmi \
+bytecomp/translmod.cmo: parsing/asttypes.cmi typing/ctype.cmi typing/env.cmi \
-    typing/ctype.cmi typing/env.cmi typing/ident.cmi bytecomp/lambda.cmi \
+    typing/ident.cmi bytecomp/lambda.cmi parsing/location.cmi \
-    parsing/location.cmi utils/misc.cmi typing/mtype.cmi typing/path.cmi \
+    parsing/longident.cmi utils/misc.cmi typing/mtype.cmi typing/path.cmi \
     typing/predef.cmi typing/primitive.cmi typing/printtyp.cmi \
     bytecomp/translclass.cmi bytecomp/translcore.cmi bytecomp/translobj.cmi \
     typing/typedtree.cmi typing/types.cmi bytecomp/translmod.cmi 
-bytecomp/translmod.cmx: parsing/asttypes.cmi utils/config.cmx \
+bytecomp/translmod.cmx: parsing/asttypes.cmi typing/ctype.cmx typing/env.cmx \
-    typing/ctype.cmx typing/env.cmx typing/ident.cmx bytecomp/lambda.cmx \
+    typing/ident.cmx bytecomp/lambda.cmx parsing/location.cmx \
-    parsing/location.cmx utils/misc.cmx typing/mtype.cmx typing/path.cmx \
+    parsing/longident.cmx utils/misc.cmx typing/mtype.cmx typing/path.cmx \
     typing/predef.cmx typing/primitive.cmx typing/printtyp.cmx \
     bytecomp/translclass.cmx bytecomp/translcore.cmx bytecomp/translobj.cmx \
     typing/typedtree.cmx typing/types.cmx bytecomp/translmod.cmi 
@@ -631,13 +635,15 @@ driver/compile.cmo: bytecomp/bytegen.cmi utils/ccomp.cmi utils/clflags.cmo \
     utils/misc.cmi parsing/parse.cmi driver/pparse.cmi parsing/printast.cmi \
     bytecomp/printinstr.cmi bytecomp/printlambda.cmi typing/printtyp.cmi \
     bytecomp/simplif.cmi bytecomp/translmod.cmi typing/typedtree.cmi \
-    typing/typemod.cmi utils/warnings.cmi driver/compile.cmi 
+    typing/typemod.cmi typing/unused_var.cmo utils/warnings.cmi \
+    driver/compile.cmi 
 driver/compile.cmx: bytecomp/bytegen.cmx utils/ccomp.cmx utils/clflags.cmx \
     utils/config.cmx bytecomp/emitcode.cmx typing/env.cmx typing/ident.cmx \
     utils/misc.cmx parsing/parse.cmx driver/pparse.cmx parsing/printast.cmx \
     bytecomp/printinstr.cmx bytecomp/printlambda.cmx typing/printtyp.cmx \
     bytecomp/simplif.cmx bytecomp/translmod.cmx typing/typedtree.cmx \
-    typing/typemod.cmx utils/warnings.cmx driver/compile.cmi 
+    typing/typemod.cmx typing/unused_var.cmx utils/warnings.cmx \
+    driver/compile.cmi 
 driver/errors.cmo: bytecomp/bytelibrarian.cmi bytecomp/bytelink.cmi \
     bytecomp/bytepackager.cmi typing/ctype.cmi typing/env.cmi \
     typing/includemod.cmi parsing/lexer.cmi parsing/location.cmi \
@@ -669,13 +675,13 @@ driver/optcompile.cmo: asmcomp/asmgen.cmi utils/ccomp.cmi utils/clflags.cmo \
     utils/misc.cmi parsing/parse.cmi driver/pparse.cmi parsing/printast.cmi \
     bytecomp/printlambda.cmi typing/printtyp.cmi bytecomp/simplif.cmi \
     bytecomp/translmod.cmi typing/typedtree.cmi typing/typemod.cmi \
-    utils/warnings.cmi driver/optcompile.cmi 
+    typing/unused_var.cmo utils/warnings.cmi driver/optcompile.cmi 
 driver/optcompile.cmx: asmcomp/asmgen.cmx utils/ccomp.cmx utils/clflags.cmx \
     asmcomp/compilenv.cmx utils/config.cmx typing/env.cmx typing/ident.cmx \
     utils/misc.cmx parsing/parse.cmx driver/pparse.cmx parsing/printast.cmx \
     bytecomp/printlambda.cmx typing/printtyp.cmx bytecomp/simplif.cmx \
     bytecomp/translmod.cmx typing/typedtree.cmx typing/typemod.cmx \
-    utils/warnings.cmx driver/optcompile.cmi 
+    typing/unused_var.cmx utils/warnings.cmx driver/optcompile.cmi 
 driver/opterrors.cmo: asmcomp/asmgen.cmi asmcomp/asmlibrarian.cmi \
     asmcomp/asmlink.cmi asmcomp/asmpackager.cmi asmcomp/compilenv.cmi \
     typing/ctype.cmi typing/env.cmi typing/includemod.cmi parsing/lexer.cmi \

Makefile

@@ -19,7 +19,7 @@ include stdlib/StdlibModules
 
 CAMLC=boot/ocamlrun boot/ocamlc -nostdlib -I boot
 CAMLOPT=boot/ocamlrun ./ocamlopt -nostdlib -I stdlib
-COMPFLAGS=-warn-error A $(INCLUDES)
+COMPFLAGS=-warn-error Ay -w Y $(INCLUDES)
 LINKFLAGS=
 
 CAMLYACC=boot/ocamlyacc
@@ -44,7 +44,7 @@ PARSING=parsing/linenum.cmo parsing/location.cmo parsing/longident.cmo \
   parsing/syntaxerr.cmo parsing/parser.cmo \
   parsing/lexer.cmo parsing/parse.cmo parsing/printast.cmo
 
-TYPING=typing/ident.cmo typing/path.cmo \
+TYPING=typing/unused_var.cmo typing/ident.cmo typing/path.cmo \
   typing/primitive.cmo typing/types.cmo \
   typing/btype.cmo typing/oprint.cmo \
   typing/subst.cmo typing/predef.cmo \

driver/compile.ml

@@ -99,6 +99,7 @@ let implementation ppf sourcefile outputprefix =
     try
       Pparse.file ppf inputfile Parse.implementation ast_impl_magic_number
       ++ print_if ppf Clflags.dump_parsetree Printast.implementation
+      ++ Unused_var.warn ppf
       ++ Typemod.type_implementation sourcefile outputprefix modulename env
       ++ Translmod.transl_implementation modulename
       ++ print_if ppf Clflags.dump_rawlambda Printlambda.lambda

driver/main_args.ml

@@ -134,9 +134,11 @@ struct
       \032    S/s enable/disable non-unit statement\n\
       \032    U/u enable/disable unused match case\n\
       \032    V/v enable/disable hidden instance variable\n\
+      \032    Y/y enable/disable unused variable\n\
+      \032    Z/z enable/disable unused variable (strict)\n\
       \032    X/x enable/disable all other warnings\n\
-      \032    default setting is \"Ale\"\n\
+      \032    default setting is \"Aelyz\"\n\
-      \032    (all warnings but labels and fragile match enabled)";
+      \032    (all warnings enabled except fragile match, labels, unused var)";
     "-warn-error" , Arg.String F._warn_error,
       "<flags>  Treat the warnings enabled by <flags> as errors.\n\
       \032    See option -w for the list of flags.\n\

driver/optcompile.ml

@@ -88,10 +88,12 @@ let implementation ppf sourcefile outputprefix =
     if !Clflags.print_types then ignore(
       Pparse.file ppf inputfile Parse.implementation ast_impl_magic_number
       ++ print_if ppf Clflags.dump_parsetree Printast.implementation
+      ++ Unused_var.warn ppf
       ++ Typemod.type_implementation sourcefile outputprefix modulename env)
     else begin
       Pparse.file ppf inputfile Parse.implementation ast_impl_magic_number
       ++ print_if ppf Clflags.dump_parsetree Printast.implementation
+      ++ Unused_var.warn ppf
       ++ Typemod.type_implementation sourcefile outputprefix modulename env
       ++ Translmod.transl_store_implementation modulename
       +++ print_if ppf Clflags.dump_rawlambda Printlambda.lambda

lex/Makefile

@@ -15,7 +15,7 @@
 # The lexer generator
 CAMLC=../boot/ocamlrun ../boot/ocamlc -nostdlib -I ../boot
 CAMLOPT=../boot/ocamlrun ../ocamlopt -nostdlib -I ../stdlib
-COMPFLAGS=-warn-error A
+COMPFLAGS=-warn-error Ay -w Y
 CAMLYACC=../boot/ocamlyacc
 YACCFLAGS=-v
 CAMLLEX=../boot/ocamlrun ../boot/ocamllex

otherlibs/bigarray/Makefile

@@ -20,7 +20,7 @@ CFLAGS=-I../../byterun -g -O $(BYTECCCOMPOPTS) $(SHAREDCCCOMPOPTS)
 CAMLC=../../ocamlcomp.sh -I ../unix
 CAMLOPT=../../ocamlcompopt.sh -I ../unix
 MKLIB=../../boot/ocamlrun ../../tools/ocamlmklib
-COMPFLAGS=-warn-error A
+COMPFLAGS=-warn-error Ay -w Y
 
 C_OBJS=bigarray_stubs.o mmap_unix.o
 

otherlibs/dbm/Makefile

@@ -22,7 +22,7 @@ CC=$(BYTECC) -g
 CAMLC=../../ocamlcomp.sh
 CAMLOPT=../../ocamlcompopt.sh
 MKLIB=../../boot/ocamlrun ../../tools/ocamlmklib
-COMPFLAGS=-warn-error A
+COMPFLAGS=-warn-error Ay -w Y
 
 CFLAGS=$(DBM_INCLUDES) -I../../byterun -O $(BYTECCCOMPOPTS) $(SHAREDCCCOMPOPTS)
 COBJS=cldbm.o

otherlibs/dynlink/Makefile

@@ -19,7 +19,7 @@ include ../../config/Makefile
 
 CAMLC=../../boot/ocamlrun ../../ocamlc
 INCLUDES=-I ../../utils -I ../../typing -I ../../bytecomp
-COMPFLAGS=-warn-error A -I ../../stdlib $(INCLUDES)
+COMPFLAGS=-warn-error Ay -w Y -I ../../stdlib $(INCLUDES)
 
 OBJS=dynlink.cmo
 COMPILEROBJS=misc.cmo config.cmo tbl.cmo clflags.cmo consistbl.cmo \

otherlibs/graph/Makefile

@@ -22,7 +22,7 @@ CFLAGS=-I../../byterun $(X11_INCLUDES) -O $(BYTECCCOMPOPTS) $(SHAREDCCCOMPOPTS)
 CAMLC=../../ocamlcomp.sh
 CAMLOPT=../../ocamlcompopt.sh
 MKLIB=../../boot/ocamlrun ../../tools/ocamlmklib
-COMPFLAGS=-warn-error A
+COMPFLAGS=-warn-error Ay -w Y
 
 OBJS=open.o draw.o fill.o color.o text.o \
   image.o make_img.o dump_img.o point_col.o sound.o events.o \

otherlibs/labltk/support/Makefile.common

@@ -15,7 +15,7 @@ INSTALLDIR=$(LIBDIR)/$(LIBNAME)
 CAMLRUN=$(TOPDIR)/boot/ocamlrun
 CAMLC=$(TOPDIR)/ocamlcomp.sh
 CAMLOPT=$(TOPDIR)/ocamlcompopt.sh
-CAMLCOMP=$(CAMLC) -c -warn-error A
+CAMLCOMP=$(CAMLC) -c -warn-error Ay -w Y
 CAMLYACC=$(TOPDIR)/boot/ocamlyacc -v
 CAMLLEX=$(CAMLRUN) $(TOPDIR)/boot/ocamllex
 CAMLLIBR=$(CAMLC) -a

otherlibs/num/Makefile

@@ -21,10 +21,10 @@ include ../../config/Makefile
 CC=$(BYTECC)
 CFLAGS=-O -I../../byterun $(BYTECCCOMPOPTS) $(SHAREDCCCOMPOPTS) \
           -DBNG_ARCH_$(BNG_ARCH) -DBNG_ASM_LEVEL=$(BNG_ASM_LEVEL)
-CAMLC=../../ocamlcomp.sh -w s
+CAMLC=../../ocamlcomp.sh
-CAMLOPT=../../ocamlcompopt.sh -w s
+CAMLOPT=../../ocamlcompopt.sh
 MKLIB=../../boot/ocamlrun ../../tools/ocamlmklib
-COMPFLAGS=-warn-error A
+COMPFLAGS=-w sY -warn-error Ay
 
 CAMLOBJS=int_misc.cmo string_misc.cmo nat.cmo big_int.cmo arith_flags.cmo \
   ratio.cmo num.cmo arith_status.cmo

otherlibs/str/Makefile

@@ -22,7 +22,7 @@ CC=$(BYTECC)
 CFLAGS=-O -I../../byterun $(BYTECCCOMPOPTS) $(SHAREDCCCOMPOPTS)
 CAMLC=../../ocamlcomp.sh
 CAMLOPT=../../ocamlcompopt.sh
-COMPFLAGS=-warn-error A
+COMPFLAGS=-warn-error Ay -w Y
 COBJS=strstubs.o
 MKLIB=../../boot/ocamlrun ../../tools/ocamlmklib
 

otherlibs/systhreads/Makefile

@@ -18,7 +18,7 @@ include ../../config/Makefile
 CAMLC=../../ocamlcomp.sh -I ../unix
 CAMLOPT=../../ocamlcompopt.sh -I ../unix
 MKLIB=../../boot/ocamlrun ../../tools/ocamlmklib
-COMPFLAGS=-warn-error A
+COMPFLAGS=-warn-error Ay -w Y
 
 BYTECODE_C_OBJS=posix_b.o
 NATIVECODE_C_OBJS=posix_n.o

otherlibs/threads/Makefile

@@ -19,7 +19,7 @@ CC=$(BYTECC)
 CFLAGS=-I../../byterun -O $(BYTECCCOMPOPTS) $(SHAREDCCCOMPOPTS) -g
 CAMLC=../../ocamlcomp.sh -I ../unix
 MKLIB=../../boot/ocamlrun ../../tools/ocamlmklib
-COMPFLAGS=-warn-error A
+COMPFLAGS=-warn-error Ay -w Y
 
 C_OBJS=scheduler.o
 

otherlibs/unix/Makefile

@@ -23,7 +23,7 @@ CFLAGS=-I../../byterun -O $(BYTECCCOMPOPTS) $(SHAREDCCCOMPOPTS)
 CAMLC=../../ocamlcomp.sh
 CAMLOPT=../../ocamlcompopt.sh
 MKLIB=../../boot/ocamlrun ../../tools/ocamlmklib
-COMPFLAGS=-warn-error A
+COMPFLAGS=-warn-error Ay -w Y
 
 OBJS=accept.o access.o addrofstr.o alarm.o bind.o chdir.o chmod.o \
   chown.o chroot.o close.o closedir.o connect.o cst2constr.o cstringv.o \

stdlib/Makefile

@@ -18,7 +18,7 @@ include ../config/Makefile
 RUNTIME=../boot/ocamlrun
 COMPILER=../ocamlc
 CAMLC=$(RUNTIME) $(COMPILER)
-COMPFLAGS=-g -warn-error A -nostdlib
+COMPFLAGS=-g -warn-error Ay -w Y -nostdlib
 OPTCOMPILER=../ocamlopt
 CAMLOPT=$(RUNTIME) $(OPTCOMPILER)
 OPTCOMPFLAGS=-warn-error A -nostdlib

stdlib/sys.ml

@@ -78,4 +78,4 @@ let catch_break on =
 
 (* OCaml version string, must be in the format described in sys.mli. *)
 
-let ocaml_version = "3.09+dev5 (2004-11-02)";;
+let ocaml_version = "3.09+dev6 (2004-11-06)";;

typing/unused_var.ml

@@ -0,0 +1,267 @@
+(***********************************************************************)
+(*                                                                     *)
+(*                           Objective Caml                            *)
+(*                                                                     *)
+(*           Damien Doligez, projet Cristal, INRIA Rocquencourt        *)
+(*                                                                     *)
+(*  Copyright 2004 Institut National de Recherche en Informatique et   *)
+(*  en Automatique.  All rights reserved.  This file is distributed    *)
+(*  under the terms of the Q Public License version 1.0.               *)
+(*                                                                     *)
+(***********************************************************************)
+
+(* $Id$ *)
+
+open Parsetree
+
+let silent v = String.length v > 0 && v.[0] = '_';;
+
+let add_vars tbl (vll1, vll2) =
+  let add_var (v, _loc, used) = Hashtbl.add tbl v used in
+  List.iter add_var vll1;
+  List.iter add_var vll2;
+;;
+
+let rm_vars tbl (vll1, vll2) =
+  let rm_var (v, _, _) = Hashtbl.remove tbl v in
+  List.iter rm_var vll1;
+  List.iter rm_var vll2;
+;;
+
+let w_lax x = Warnings.Unused_var x;;
+let w_strict x = Warnings.Unused_var_strict x;;
+let w_either x =
+  if Warnings.is_active (w_strict x) then w_strict x else w_lax x
+;;
+
+let check_rm_vars ppf tbl (vlul_pat, vlul_as) =
+  let check_rm_var kind (v, loc, used) =
+    if not !used && not (silent v)
+    then Location.print_warning loc ppf (kind v);
+    Hashtbl.remove tbl v;
+  in
+  List.iter (check_rm_var w_strict) vlul_pat;
+  List.iter (check_rm_var w_either) vlul_as;
+;;
+
+let check_rm_let ppf tbl vlulpl =
+  if Warnings.is_active (w_strict "") then begin
+    List.iter (check_rm_vars ppf tbl) vlulpl;
+  end else begin
+    let check_rm_one flag (v, loc, used) =
+      Hashtbl.remove tbl v;
+      flag && (silent v || not !used)
+    in
+    let warn_var (v, loc, used) =
+      if not (silent v) && not !used
+      then Location.print_warning loc ppf (w_lax v)
+    in
+    let check_rm_pat (def, def_as) =
+      let def_unused = List.fold_left check_rm_one true def in
+      let all_unused = List.fold_left check_rm_one def_unused def_as in
+      if all_unused then List.iter warn_var def;
+      List.iter warn_var def_as;
+    in
+    List.iter check_rm_pat vlulpl;
+  end;
+;;
+
+let rec get_vars ((vacc, asacc) as acc) p =
+  match p.ppat_desc with
+  | Ppat_any -> acc
+  | Ppat_var v -> ((v, p.ppat_loc, ref false) :: vacc, asacc)
+  | Ppat_alias (pp, v) ->
+      get_vars (vacc, ((v, p.ppat_loc, ref false) :: asacc)) pp
+  | Ppat_constant _ -> acc
+  | Ppat_tuple pl -> List.fold_left get_vars acc pl
+  | Ppat_construct (_, po, _) -> get_vars_option acc po
+  | Ppat_variant (_, po) -> get_vars_option acc po
+  | Ppat_record ipl ->
+      List.fold_left (fun a (_, p) -> get_vars a p) acc ipl
+  | Ppat_array pl -> List.fold_left get_vars acc pl
+  | Ppat_or (p1, _p2) -> get_vars acc p1
+  | Ppat_constraint (pp, _) -> get_vars acc pp
+  | Ppat_type _ -> acc
+
+and get_vars_option acc po =
+  match po with
+  | Some p -> get_vars acc p
+  | None -> acc
+;;
+
+let get_pel_vars pel =
+  List.map (fun (p, _) -> get_vars ([], []) p) pel
+;;
+
+let rec structure ppf tbl l =
+  List.iter (structure_item ppf tbl) l
+
+and structure_item ppf tbl s =
+  match s.pstr_desc with
+  | Pstr_eval e -> expression ppf tbl e;
+  | Pstr_value (recflag, pel) -> let_pel ppf tbl recflag pel None;
+  | Pstr_primitive _ -> ()
+  | Pstr_type _ -> ()
+  | Pstr_exception _ -> ()
+  | Pstr_exn_rebind _ -> ()
+  | Pstr_module (_, me) -> module_expr ppf tbl me;
+  | Pstr_recmodule stml ->
+      List.iter (fun (_, _, me) -> module_expr ppf tbl me) stml;
+  | Pstr_modtype _ -> ()
+  | Pstr_open _ -> ()
+  | Pstr_class cdl -> List.iter (class_declaration ppf tbl) cdl;
+  | Pstr_class_type _ -> ()
+  | Pstr_include _ -> ()
+
+and expression ppf tbl e =
+  match e.pexp_desc with
+  | Pexp_ident (Longident.Lident id) ->
+      begin try (Hashtbl.find tbl id) := true;
+      with Not_found -> ()
+      end;
+  | Pexp_ident _ -> ()
+  | Pexp_constant _ -> ()
+  | Pexp_let (recflag, pel, e) ->
+      let_pel ppf tbl recflag pel (Some (fun ppf tbl -> expression ppf tbl e));
+  | Pexp_function (_, eo, pel) ->
+      expression_option ppf tbl eo;
+      match_pel ppf tbl pel;
+  | Pexp_apply (e, lel) ->
+      expression ppf tbl e;
+      List.iter (fun (_, e) -> expression ppf tbl e) lel;
+  | Pexp_match (e, pel) ->
+      expression ppf tbl e;
+      match_pel ppf tbl pel;
+  | Pexp_try (e, pel) ->
+      expression ppf tbl e;
+      match_pel ppf tbl pel;
+  | Pexp_tuple el -> List.iter (expression ppf tbl) el;
+  | Pexp_construct (_, eo, _) -> expression_option ppf tbl eo;
+  | Pexp_variant (_, eo) -> expression_option ppf tbl eo;
+  | Pexp_record (iel, eo) ->
+      List.iter (fun (_, e) -> expression ppf tbl e) iel;
+      expression_option ppf tbl eo;
+  | Pexp_field (e, _) -> expression ppf tbl e;
+  | Pexp_setfield (e1, _, e2) ->
+      expression ppf tbl e1;
+      expression ppf tbl e2;
+  | Pexp_array el -> List.iter (expression ppf tbl) el;
+  | Pexp_ifthenelse (e1, e2, eo) ->
+      expression ppf tbl e1;
+      expression ppf tbl e2;
+      expression_option ppf tbl eo;
+  | Pexp_sequence (e1, e2) ->
+      expression ppf tbl e1;
+      expression ppf tbl e2;
+  | Pexp_while (e1, e2) ->
+      expression ppf tbl e1;
+      expression ppf tbl e2;
+  | Pexp_for (id, e1, e2, _, e3) ->
+      expression ppf tbl e1;
+      expression ppf tbl e2;
+      let defined = ([ (id, e.pexp_loc, ref false) ], []) in
+      add_vars tbl defined;
+      expression ppf tbl e3;
+      check_rm_vars ppf tbl defined;
+  | Pexp_constraint (e, _, _) -> expression ppf tbl e;
+  | Pexp_when (e1, e2) ->
+      expression ppf tbl e1;
+      expression ppf tbl e2;
+  | Pexp_send (e, _) -> expression ppf tbl e;
+  | Pexp_new _ -> ()
+  | Pexp_setinstvar (_, e) -> expression ppf tbl e;
+  | Pexp_override sel -> List.iter (fun (_, e) -> expression ppf tbl e) sel;
+  | Pexp_letmodule (_, me, e) ->
+      module_expr ppf tbl me;
+      expression ppf tbl e;
+  | Pexp_assert e -> expression ppf tbl e;
+  | Pexp_assertfalse -> ()
+  | Pexp_lazy e -> expression ppf tbl e;
+  | Pexp_poly (e, _) -> expression ppf tbl e;
+  | Pexp_object cs -> class_structure ppf tbl cs;
+
+and expression_option ppf tbl eo =
+  match eo with
+  | Some e -> expression ppf tbl e;
+  | None -> ()
+
+and let_pel ppf tbl recflag pel body =
+  match recflag with
+  | Asttypes.Recursive ->
+      let defined = get_pel_vars pel in
+      List.iter (add_vars tbl) defined;
+      List.iter (fun (_, e) -> expression ppf tbl e) pel;
+      begin match body with
+      | None ->
+          List.iter (rm_vars tbl) defined;
+      | Some f ->
+          f ppf tbl;
+          check_rm_let ppf tbl defined;
+      end;
+  | _ ->
+      List.iter (fun (_, e) -> expression ppf tbl e) pel;
+      begin match body with
+      | None -> ()
+      | Some f ->
+          let defined = get_pel_vars pel in
+          List.iter (add_vars tbl) defined;
+          f ppf tbl;
+          check_rm_let ppf tbl defined;
+      end;
+
+and match_pel ppf tbl pel =
+  List.iter (match_pe ppf tbl) pel
+
+and match_pe ppf tbl (p, e) =
+ let defined = get_vars ([], []) p in
+  add_vars tbl defined;
+  expression ppf tbl e;
+  check_rm_vars ppf tbl defined;
+
+and module_expr ppf tbl me =
+  match me.pmod_desc with
+  | Pmod_ident _ -> ()
+  | Pmod_structure s -> structure ppf tbl s
+  | Pmod_functor (_, _, me) -> module_expr ppf tbl me
+  | Pmod_apply (me1, me2) ->
+      module_expr ppf tbl me1;
+      module_expr ppf tbl me2;
+  | Pmod_constraint (me, _) -> module_expr ppf tbl me
+
+and class_declaration ppf tbl cd = class_expr ppf tbl cd.pci_expr
+
+and class_expr ppf tbl ce =
+  match ce.pcl_desc with
+  | Pcl_constr _ -> ()
+  | Pcl_structure cs -> class_structure ppf tbl cs
+  | Pcl_fun (_, _, _, ce) -> class_expr ppf tbl ce
+  | Pcl_apply (ce, _) -> class_expr ppf tbl ce
+  | Pcl_let (recflag, pel, ce) ->
+      let_pel ppf tbl recflag pel (Some (fun ppf tbl -> class_expr ppf tbl ce));
+  | Pcl_constraint (ce, _) -> class_expr ppf tbl ce;
+
+and class_structure ppf tbl (p, cfl) =
+  let defined = get_vars ([], []) p in
+  add_vars tbl defined;
+  List.iter (class_field ppf tbl) cfl;
+  check_rm_vars ppf tbl defined;
+
+and class_field ppf tbl cf =
+  match cf with
+  | Pcf_inher (ce, _) -> class_expr ppf tbl ce;
+  | Pcf_val (_, _, e, _) -> expression ppf tbl e;
+  | Pcf_virt _ -> ()
+  | Pcf_meth (_, _, e, _) -> expression ppf tbl e;
+  | Pcf_cstr _ -> ()
+  | Pcf_let (recflag, pel, _) -> let_pel ppf tbl recflag pel None;
+  | Pcf_init e -> expression ppf tbl e;
+;;
+
+let warn ppf ast =
+  if Warnings.is_active (w_lax "") || Warnings.is_active (w_strict "")
+  then begin
+    let tbl = Hashtbl.create 97 in
+    structure ppf tbl ast;
+  end;
+  ast
+;;

utils/warnings.ml

@@ -27,12 +27,14 @@ type t =                             (* A is all *)
   | Unused_pat                       (* U *)
   | Hide_instance_variable of string (* V *)
   | Other of string                  (* X *)
+  | Unused_var of string             (* Y *)
+  | Unused_var_strict of string      (* Z *)
 ;;
 
 let letter = function        (* 'a' is all *)
   | Comment _ ->                'c'
   | Deprecated ->               'd'
-  | Fragile_pat _ ->              'e'
+  | Fragile_pat _ ->            'e'
   | Partial_application ->      'f'
   | Labels_omitted ->           'l'
   | Method_override _ ->        'm'
@@ -41,10 +43,12 @@ let letter = function        (* 'a' is all *)
   | Unused_match|Unused_pat ->  'u'
   | Hide_instance_variable _ -> 'v'
   | Other _ ->                  'x'
+  | Unused_var _ ->             'y'
+  | Unused_var_strict _ ->      'z'
 ;;
 
 let check c =
-  try ignore (String.index "acdeflmpsuvxACDEFLMPSUVX" c)
+  try ignore (String.index "acdeflmpsuvxyzACDEFLMPSUVXYZ" c)
   with _ -> raise (Arg.Bad (Printf.sprintf "unknown warning option %c" c))
 ;;    
 
@@ -81,7 +85,7 @@ let parse_options iserr s =
   done
 ;;
 
-let () = parse_options false "el";;
+let () = parse_options false "elyz";;
 
 let message = function
   | Partial_match "" -> "this pattern-matching is not exhaustive."
@@ -113,6 +117,7 @@ let message = function
       "this expression should have type unit."
   | Comment s -> "this is " ^ s ^ "."
   | Deprecated -> "this syntax is deprecated."
+  | Unused_var v | Unused_var_strict v -> "unused variable " ^ v ^ "."
   | Other s -> s
 ;;
 

utils/warnings.mli

@@ -27,6 +27,8 @@ type t =                             (* A is all *)
   | Unused_pat                       (* U *)
   | Hide_instance_variable of string (* V *)
   | Other of string                  (* X *)
+  | Unused_var of string             (* Y *)
+  | Unused_var_strict of string      (* Z *)
 ;;
 
 val parse_options : bool -> string -> unit;;