diff --git a/infer/src/IR/Cg.re b/infer/src/IR/Cg.re
index 12fd5f722..43246d319 100644
--- a/infer/src/IR/Cg.re
+++ b/infer/src/IR/Cg.re
@@ -386,7 +386,7 @@ let pp_graph_dotty get_specs (g: t) fmt => {
     | exn when SymOp.exn_not_failure exn => (-1)
     };
   let get_color (n, _) =>
-    if (num_specs n !== 0) {
+    if (num_specs n != 0) {
       "green"
     } else {
       "red"
@@ -434,5 +434,5 @@ let save_call_graph_dotty source get_specs (g: t) => {
   let outc = open_out (DB.filename_to_string fname_dot);
   let fmt = F.formatter_of_out_channel outc;
   pp_graph_dotty get_specs g fmt;
-  close_out outc
+  Out_channel.close outc
 };
diff --git a/infer/src/IR/DecompiledExp.re b/infer/src/IR/DecompiledExp.re
index a4b94ed2c..82a64f9c5 100644
--- a/infer/src/IR/DecompiledExp.re
+++ b/infer/src/IR/DecompiledExp.re
@@ -145,7 +145,7 @@ let pp_vpath pe fmt vpath => {
     fun
     | Some de => pp fmt de
     | None => ();
-  if (pe.Pp.kind === Pp.HTML) {
+  if (pe.Pp.kind == Pp.HTML) {
     F.fprintf
       fmt
       " %a{vpath: %a}%a"
diff --git a/infer/src/IR/Errlog.ml b/infer/src/IR/Errlog.ml
index 2857d7838..0d2e4cc5c 100644
--- a/infer/src/IR/Errlog.ml
+++ b/infer/src/IR/Errlog.ml
@@ -109,14 +109,14 @@ let size filter (err_log: t) =
 (** Print errors from error log *)
 let pp_errors fmt (errlog : t) =
   let f (ekind, _, ename, _, _) _ =
-    if ekind == Exceptions.Kerror then
+    if ekind = Exceptions.Kerror then
       F.fprintf fmt "%a@ " Localise.pp ename in
   ErrLogHash.iter f errlog
 
 (** Print warnings from error log *)
 let pp_warnings fmt (errlog : t) =
   let f (ekind, _, ename, desc, _) _ =
-    if ekind == Exceptions.Kwarning then
+    if ekind = Exceptions.Kwarning then
       F.fprintf fmt "%a %a@ " Localise.pp ename Localise.pp_error_desc desc in
   ErrLogHash.iter f errlog
 
@@ -128,7 +128,7 @@ let pp_html source path_to_root fmt (errlog: t) =
       Io_infer.Html.pp_session_link source path_to_root fmt (nodeid, session, loc.Location.line) in
     ErrDataSet.iter (pp_nodeid_session_loc fmt) eds in
   let f do_fp ek (ekind, infp, err_name, desc, _) eds =
-    if ekind == ek && do_fp == infp
+    if ekind = ek && do_fp = infp
     then
       F.fprintf fmt "<br>%a %a %a"
         Localise.pp err_name
@@ -195,8 +195,8 @@ let log_issue _ekind err_log loc node_id_key session ltr exn =
         not Mleak_buckets.should_raise_leak_unknown_origin
     | _ -> false in
   let log_it =
-    visibility == Exceptions.Exn_user ||
-    (Config.developer_mode && visibility == Exceptions.Exn_developer) in
+    visibility = Exceptions.Exn_user ||
+    (Config.developer_mode && visibility = Exceptions.Exn_developer) in
   if log_it && not hide_java_loc_zero && not hide_memory_error then begin
     let added =
       add_issue err_log
diff --git a/infer/src/IR/Exceptions.ml b/infer/src/IR/Exceptions.ml
index 5955f9189..ef5f18fd2 100644
--- a/infer/src/IR/Exceptions.ml
+++ b/infer/src/IR/Exceptions.ml
@@ -355,4 +355,4 @@ let pp_err (_, node_key) loc ekind ex_name desc ml_loc_opt fmt () =
 (** Return true if the exception is not serious and should be handled in timeout mode *)
 let handle_exception exn =
   let _, _, _, visibility, _, _, _ = recognize_exception exn in
-  visibility == Exn_user || visibility == Exn_developer
+  visibility = Exn_user || visibility = Exn_developer
diff --git a/infer/src/IR/Ident.re b/infer/src/IR/Ident.re
index d73a3e5d7..faca965da 100644
--- a/infer/src/IR/Ident.re
+++ b/infer/src/IR/Ident.re
@@ -78,7 +78,7 @@ let path_ident_stamp = (-3);
 type t = {kind: kind, name: Name.t, stamp: int} [@@deriving compare];
 
 /* most unlikely first */
-let equal i1 i2 => i1.stamp === i2.stamp && i1.kind === i2.kind && equal_name i1.name i2.name;
+let equal i1 i2 => i1.stamp == i2.stamp && i1.kind == i2.kind && equal_name i1.name i2.name;
 
 
 /** {2 Set for identifiers} */
@@ -254,9 +254,9 @@ let name_return = Mangled.from_string "return";
 
 /** Return the standard name for the given kind */
 let standard_name kind =>
-  if (kind === KNormal || kind === KNone) {
+  if (kind == KNormal || kind == KNone) {
     Name.Normal
-  } else if (kind === KFootprint) {
+  } else if (kind == KFootprint) {
     Name.Footprint
   } else {
     Name.Primed
@@ -297,20 +297,20 @@ let create_footprint name stamp => create_with_stamp KFootprint name stamp;
 /** Get a name of an identifier */
 let get_name id => id.name;
 
-let is_primed (id: t) => id.kind === KPrimed;
+let is_primed (id: t) => id.kind == KPrimed;
 
-let is_normal (id: t) => id.kind === KNormal || id.kind === KNone;
+let is_normal (id: t) => id.kind == KNormal || id.kind == KNone;
 
-let is_footprint (id: t) => id.kind === KFootprint;
+let is_footprint (id: t) => id.kind == KFootprint;
 
 let is_none (id: t) => id.kind == KNone;
 
-let is_path (id: t) => id.kind === KNormal && id.stamp == path_ident_stamp;
+let is_path (id: t) => id.kind == KNormal && id.stamp == path_ident_stamp;
 
 let make_unprimed id =>
   if (id.kind != KPrimed) {
     assert false
-  } else if (id.kind === KNone) {
+  } else if (id.kind == KNone) {
     {...id, kind: KNone}
   } else {
     {...id, kind: KNormal}
@@ -333,14 +333,14 @@ let create_path pathstring =>
 
 /** Convert an identifier to a string. */
 let to_string id =>
-  if (id.kind === KNone) {
+  if (id.kind == KNone) {
     "_"
   } else {
     let base_name = name_to_string id.name;
     let prefix =
-      if (id.kind === KFootprint) {
+      if (id.kind == KFootprint) {
         "@"
-      } else if (id.kind === KNormal) {
+      } else if (id.kind == KNormal) {
         ""
       } else {
         "_"
diff --git a/infer/src/IR/Localise.ml b/infer/src/IR/Localise.ml
index 066cb98ad..af3f988a2 100644
--- a/infer/src/IR/Localise.ml
+++ b/infer/src/IR/Localise.ml
@@ -229,7 +229,7 @@ let _line_tag tags tag loc =
   let line_str = string_of_int loc.Location.line in
   Tags.add tags tag line_str;
   let s = "line " ^ line_str in
-  if (loc.Location.col != -1) then
+  if (loc.Location.col <> -1) then
     let col_str = string_of_int loc.Location.col in
     s ^ ", column " ^ col_str
   else s
diff --git a/infer/src/IR/Location.re b/infer/src/IR/Location.re
index 4d01103fb..de3aaa582 100644
--- a/infer/src/IR/Location.re
+++ b/infer/src/IR/Location.re
@@ -37,7 +37,7 @@ let pp f (loc: t) => F.fprintf f "[line %d]" loc.line;
 
 let to_string loc => {
   let s = string_of_int loc.line;
-  if (loc.col !== (-1)) {
+  if (loc.col != (-1)) {
     s ^ ":" ^ string_of_int loc.col
   } else {
     s
diff --git a/infer/src/IR/Procdesc.re b/infer/src/IR/Procdesc.re
index f0baacd56..e54ad2853 100644
--- a/infer/src/IR/Procdesc.re
+++ b/infer/src/IR/Procdesc.re
@@ -325,7 +325,7 @@ let compute_distance_to_exit_node pdesc => {
         next_nodes := node.preds @ !next_nodes
       };
     IList.iter do_node nodes;
-    if (!next_nodes !== []) {
+    if (!next_nodes != []) {
       mark_distance (dist + 1) !next_nodes
     }
   };
diff --git a/infer/src/IR/Sil.re b/infer/src/IR/Sil.re
index 0b5b6f4b3..d26ff07ae 100644
--- a/infer/src/IR/Sil.re
+++ b/infer/src/IR/Sil.re
@@ -204,7 +204,7 @@ type hpred = hpred0 inst;
 
 /** Comparsion between heap predicates. Reverse natural order, and order first by anchor exp. */
 let compare_hpred inst::inst=false hpred1 hpred2 =>
-  if (hpred1 === hpred2) {
+  if (phys_equal hpred1 hpred2) {
     0
   } else {
     switch (hpred1, hpred2) {
@@ -311,18 +311,18 @@ let module HpredSet = Caml.Set.Make {
 
 /** Begin change color if using diff printing, return updated printenv and change status */
 let color_pre_wrapper pe f x =>
-  if (Config.print_using_diff && pe.Pp.kind !== Pp.TEXT) {
+  if (Config.print_using_diff && pe.Pp.kind != Pp.TEXT) {
     let color = pe.Pp.cmap_norm (Obj.repr x);
-    if (color !== pe.Pp.color) {
+    if (color != pe.Pp.color) {
       (
-        if (pe.Pp.kind === Pp.HTML) {
+        if (pe.Pp.kind == Pp.HTML) {
           Io_infer.Html.pp_start_color
         } else {
           Latex.pp_color
         }
       )
         f color;
-      if (color === Pp.Red) {
+      if (color == Pp.Red) {
         (
           Pp.{
             /** All subexpressiona red */
@@ -346,7 +346,7 @@ let color_pre_wrapper pe f x =>
 /** Close color annotation if changed */
 let color_post_wrapper changed pe f =>
   if changed {
-    if (pe.Pp.kind === Pp.HTML) {
+    if (pe.Pp.kind == Pp.HTML) {
       Io_infer.Html.pp_end_color f ()
     } else {
       Latex.pp_color f pe.Pp.color
@@ -719,8 +719,8 @@ let module Predicates: {
       which are then visited as well.
       Can be applied only once, as it destroys the todo list */
   let iter (env: env) f f_dll =>
-    while (env.todo !== [] || env.todo_dll !== []) {
-      if (env.todo !== []) {
+    while (env.todo != [] || env.todo_dll != []) {
+      if (env.todo != []) {
         let hpara = IList.hd env.todo;
         let () = env.todo = IList.tl env.todo;
         let (n, emitted) = HparaHash.find env.hash hpara;
@@ -728,7 +728,7 @@ let module Predicates: {
           f n hpara
         }
       } else if (
-        env.todo_dll !== []
+        env.todo_dll != []
       ) {
         let hpara_dll = IList.hd env.todo_dll;
         let () = env.todo_dll = IList.tl env.todo_dll;
@@ -916,7 +916,7 @@ let update_inst inst_old inst_new => {
 /** describe an instrumentation with a string */
 let pp_inst pe f inst => {
   let str = inst_to_string inst;
-  if (pe.Pp.kind === Pp.HTML) {
+  if (pe.Pp.kind == Pp.HTML) {
     F.fprintf f " %a%s%a" Io_infer.Html.pp_start_color Pp.Orange str Io_infer.Html.pp_end_color ()
   } else {
     F.fprintf f "%s%s%s" (Binop.str pe Lt) str (Binop.str pe Gt)
@@ -1833,7 +1833,7 @@ let rec exp_sub_ids (f: Ident.t => Exp.t) exp =>
   | Lvar _ => exp
   | Exn e =>
     let e' = exp_sub_ids f e;
-    if (e' === e) {
+    if (phys_equal e' e) {
       exp
     } else {
       Exp.Exn e'
@@ -1844,7 +1844,7 @@ let rec exp_sub_ids (f: Ident.t => Exp.t) exp =>
         (
           fun ((e, pvar, typ) as captured) => {
             let e' = exp_sub_ids f e;
-            if (e' === e) {
+            if (phys_equal e' e) {
               captured
             } else {
               (e', pvar, typ)
@@ -1852,7 +1852,7 @@ let rec exp_sub_ids (f: Ident.t => Exp.t) exp =>
           }
         )
         c.captured_vars;
-    if (captured_vars === c.captured_vars) {
+    if (phys_equal captured_vars c.captured_vars) {
       exp
     } else {
       Exp.Closure {...c, captured_vars}
@@ -1860,14 +1860,14 @@ let rec exp_sub_ids (f: Ident.t => Exp.t) exp =>
   | Const (Cint _ | Cfun _ | Cstr _ | Cfloat _ | Cclass _ | Cptr_to_fld _) => exp
   | Cast t e =>
     let e' = exp_sub_ids f e;
-    if (e' === e) {
+    if (phys_equal e' e) {
       exp
     } else {
       Exp.Cast t e'
     }
   | UnOp op e typ_opt =>
     let e' = exp_sub_ids f e;
-    if (e' === e) {
+    if (phys_equal e' e) {
       exp
     } else {
       Exp.UnOp op e' typ_opt
@@ -1875,14 +1875,14 @@ let rec exp_sub_ids (f: Ident.t => Exp.t) exp =>
   | BinOp op e1 e2 =>
     let e1' = exp_sub_ids f e1;
     let e2' = exp_sub_ids f e2;
-    if (e1' === e1 && e2' === e2) {
+    if (phys_equal e1' e1 && phys_equal e2' e2) {
       exp
     } else {
       Exp.BinOp op e1' e2'
     }
   | Lfield e fld typ =>
     let e' = exp_sub_ids f e;
-    if (e' === e) {
+    if (phys_equal e' e) {
       exp
     } else {
       Exp.Lfield e' fld typ
@@ -1890,7 +1890,7 @@ let rec exp_sub_ids (f: Ident.t => Exp.t) exp =>
   | Lindex e1 e2 =>
     let e1' = exp_sub_ids f e1;
     let e2' = exp_sub_ids f e2;
-    if (e1' === e1 && e2' === e2) {
+    if (phys_equal e1' e1 && phys_equal e2' e2) {
       exp
     } else {
       Exp.Lindex e1' e2'
@@ -1899,7 +1899,7 @@ let rec exp_sub_ids (f: Ident.t => Exp.t) exp =>
     switch l_opt {
     | Some l =>
       let l' = exp_sub_ids f l;
-      if (l' === l) {
+      if (phys_equal l' l) {
         exp
       } else {
         Exp.Sizeof t (Some l') s
@@ -1938,7 +1938,7 @@ let instr_sub_ids sub_id_binders::sub_id_binders (f: Ident.t => Exp.t) instr =>
         id
       };
     let rhs_exp' = exp_sub_ids f rhs_exp;
-    if (id' === id && rhs_exp' === rhs_exp) {
+    if (phys_equal id' id && phys_equal rhs_exp' rhs_exp) {
       instr
     } else {
       Load id' rhs_exp' typ loc
@@ -1946,7 +1946,7 @@ let instr_sub_ids sub_id_binders::sub_id_binders (f: Ident.t => Exp.t) instr =>
   | Store lhs_exp typ rhs_exp loc =>
     let lhs_exp' = exp_sub_ids f lhs_exp;
     let rhs_exp' = exp_sub_ids f rhs_exp;
-    if (lhs_exp' === lhs_exp && rhs_exp' === rhs_exp) {
+    if (phys_equal lhs_exp' lhs_exp && phys_equal rhs_exp' rhs_exp) {
       instr
     } else {
       Store lhs_exp' typ rhs_exp' loc
@@ -1969,7 +1969,7 @@ let instr_sub_ids sub_id_binders::sub_id_binders (f: Ident.t => Exp.t) instr =>
         (
           fun ((actual, typ) as actual_pair) => {
             let actual' = exp_sub_ids f actual;
-            if (actual' === actual) {
+            if (phys_equal actual' actual) {
               actual_pair
             } else {
               (actual', typ)
@@ -1977,21 +1977,21 @@ let instr_sub_ids sub_id_binders::sub_id_binders (f: Ident.t => Exp.t) instr =>
           }
         )
         actuals;
-    if (ret_id' === ret_id && fun_exp' === fun_exp && actuals' === actuals) {
+    if (phys_equal ret_id' ret_id && phys_equal fun_exp' fun_exp && phys_equal actuals' actuals) {
       instr
     } else {
       Call ret_id' fun_exp' actuals' call_flags loc
     }
   | Prune exp loc true_branch if_kind =>
     let exp' = exp_sub_ids f exp;
-    if (exp' === exp) {
+    if (phys_equal exp' exp) {
       instr
     } else {
       Prune exp' loc true_branch if_kind
     }
   | Remove_temps ids loc =>
     let ids' = IList.map_changed sub_id ids;
-    if (ids' === ids) {
+    if (phys_equal ids' ids) {
       instr
     } else {
       Remove_temps ids' loc
diff --git a/infer/src/IR/Tenv.re b/infer/src/IR/Tenv.re
index 276275bd9..b9df27e30 100644
--- a/infer/src/IR/Tenv.re
+++ b/infer/src/IR/Tenv.re
@@ -137,7 +137,7 @@ let store_to_file (filename: DB.filename) (tenv: t) => {
     let out_channel = open_out debug_filename;
     let fmt = Format.formatter_of_out_channel out_channel;
     Format.fprintf fmt "%a" pp tenv;
-    close_out out_channel
+    Out_channel.close out_channel
   }
 };
 
diff --git a/infer/src/Makefile b/infer/src/Makefile
index f3ef448fe..8ad34f4f1 100644
--- a/infer/src/Makefile
+++ b/infer/src/Makefile
@@ -33,7 +33,7 @@ OCAMLBUILD_OPTIONS = \
   -cflags -principal \
   -cflags -strict-formats \
   -cflags -strict-sequence \
-  -cflags -w,$(OCAML_FATAL_WARNINGS)-3-4-9-32-40-41-42-45-48 \
+  -cflags -w,$(OCAML_FATAL_WARNINGS)-4-9-32-40-41-42-45-48 \
   -tag-line "<*{clang/clang_ast_*,backend/jsonbug_*,checkers/stacktree_*}>: warn(-27-32-35-39)" \
   -tag-line "<*/{,*/}*.{ml,re}{,i}>: package(ppx_compare)" \
   -tag thread \
diff --git a/infer/src/backend/Attribute.ml b/infer/src/backend/Attribute.ml
index 55ab60d7f..614686809 100644
--- a/infer/src/backend/Attribute.ml
+++ b/infer/src/backend/Attribute.ml
@@ -48,7 +48,7 @@ let add_or_replace_check_changed tenv check_attribute_change prop atom0 =
             atom in
       let pi = prop.Prop.pi in
       let pi' = IList.map_changed atom_map pi in
-      if pi == pi'
+      if phys_equal pi pi'
       then Prop.prop_atom_and tenv prop natom
       else Prop.normalize tenv (Prop.set prop ~pi:pi')
   | _ ->
@@ -127,7 +127,7 @@ let has_dangling_uninit tenv prop exp =
 let filter_atoms tenv ~f prop =
   let pi0 = prop.Prop.pi in
   let pi1 = IList.filter_changed f pi0 in
-  if pi1 == pi0 then
+  if phys_equal pi1 pi0 then
     prop
   else
     Prop.normalize tenv (Prop.set prop ~pi:pi1)
@@ -166,7 +166,7 @@ let map_resource tenv prop f =
     | atom -> atom in
   let pi0 = prop.Prop.pi in
   let pi1 = IList.map_changed atom_map pi0 in
-  if pi1 == pi0 then
+  if phys_equal pi1 pi0 then
     prop
   else
     Prop.normalize tenv (Prop.set prop ~pi:pi1)
diff --git a/infer/src/backend/InferPrint.re b/infer/src/backend/InferPrint.re
index e03bd32d4..d68e844fc 100644
--- a/infer/src/backend/InferPrint.re
+++ b/infer/src/backend/InferPrint.re
@@ -1403,7 +1403,7 @@ let pp_summary_and_issues formats_by_report_kind => {
   let iterate_summaries = AnalysisResults.get_summary_iterator ();
   let top_proc = TopProcedures.create ();
   let top_proc_set = TopProcedures.top_set top_proc;
-  if (!compute_top_procedures && (Config.procs_csv !== None || Config.procs_xml !== None)) {
+  if (!compute_top_procedures && (Config.procs_csv != None || Config.procs_xml != None)) {
     iterate_summaries (TopProcedures.process_summary top_proc)
   };
   iterate_summaries (process_summary filters formats_by_report_kind linereader stats top_proc_set);
diff --git a/infer/src/backend/PerfStats.ml b/infer/src/backend/PerfStats.ml
index 07af21e05..11ad6dc73 100644
--- a/infer/src/backend/PerfStats.ml
+++ b/infer/src/backend/PerfStats.ml
@@ -148,7 +148,7 @@ let register_report_at_exit file =
           Unix.mkdir_p (Filename.dirname file);
           let stats_oc = open_out file in
           Yojson.Basic.pretty_to_channel stats_oc json_stats ;
-          close_out stats_oc
+          Out_channel.close stats_oc
         with exc ->
           Format.eprintf "Info: failed to write stats to %s@\n%s@\n%s@\n%s@."
             file (Exn.to_string exc) (Yojson.Basic.pretty_to_string json_stats)
diff --git a/infer/src/backend/absarray.ml b/infer/src/backend/absarray.ml
index e0c2e5fd1..ab1aff7bb 100644
--- a/infer/src/backend/absarray.ml
+++ b/infer/src/backend/absarray.ml
@@ -218,7 +218,7 @@ end = struct
 
   (** Replace the current hpred *)
   let replace_hpred ((sigma, hpred, _) : t) hpred' =
-    IList.map (fun hpred'' -> if hpred''== hpred then hpred' else hpred'') sigma
+    IList.map (fun hpred'' -> if phys_equal hpred'' hpred then hpred' else hpred'') sigma
 
   (** Replace the strexp at the given offset in the given hpred *)
   let hpred_replace_strexp tenv footprint_part hpred syn_offs update =
@@ -441,7 +441,7 @@ let keep_only_indices tenv
       | Sil.Earray (len, esel, inst) ->
           let esel', esel_leftover' =
             IList.partition (fun (e, _) -> IList.exists (Exp.equal e) indices) esel in
-          if esel_leftover' == [] then (sigma, false)
+          if esel_leftover' = [] then (sigma, false)
           else begin
             let se' = Sil.Earray (len, esel', inst) in
             let sigma' = StrexpMatch.replace_strexp tenv footprint_part matched se' in
@@ -479,7 +479,7 @@ let strexp_do_abstract tenv
       if Config.trace_absarray then (L.d_str "keep "; d_keys keep_keys; L.d_ln ());
       keep p path keep_keys in
     let p3, changed3 =
-      if blur_keys == [] then (p2, false)
+      if blur_keys = [] then (p2, false)
       else begin
         if Config.trace_absarray then (L.d_str "blur "; d_keys blur_keys; L.d_ln ());
         blur p2 path blur_keys
@@ -493,7 +493,7 @@ let strexp_do_abstract tenv
     let keep_ksel, remove_ksel = IList.partition should_keep ksel in
     let keep_keys, _, _ =
       IList.map fst keep_ksel, IList.map fst remove_ksel, IList.map fst ksel in
-    let keep_keys' = if keep_keys == [] then default_keys else keep_keys in
+    let keep_keys' = if keep_keys = [] then default_keys else keep_keys in
     abstract keep_keys' keep_keys' in
   let do_array_footprint esel =
     (* array case footprint: keep only the last index, and blur it *)
@@ -512,7 +512,7 @@ let strexp_do_abstract tenv
   let filter_abstract d_keys should_keep abstract ksel default_keys =
     let keep_ksel = IList.filter should_keep ksel in
     let keep_keys = IList.map fst keep_ksel in
-    let keep_keys' = if keep_keys == [] then default_keys else keep_keys in
+    let keep_keys' = if keep_keys = [] then default_keys else keep_keys in
     if Config.trace_absarray then (L.d_str "keep "; d_keys keep_keys'; L.d_ln ());
     abstract keep_keys' [] in
   let do_array_reexecution esel =
diff --git a/infer/src/backend/clusterMakefile.ml b/infer/src/backend/clusterMakefile.ml
index cd1a57bfb..aef233aea 100644
--- a/infer/src/backend/clusterMakefile.ml
+++ b/infer/src/backend/clusterMakefile.ml
@@ -71,4 +71,4 @@ let create_cluster_makefile (clusters: Cluster.t list) (fname: string) =
   pp_prolog fmt clusters;
   IList.iteri do_cluster clusters;
   pp_epilog fmt () ;
-  close_out outc
+  Out_channel.close outc
diff --git a/infer/src/backend/crashcontext.ml b/infer/src/backend/crashcontext.ml
index 3629e0a44..991a65003 100644
--- a/infer/src/backend/crashcontext.ml
+++ b/infer/src/backend/crashcontext.ml
@@ -73,7 +73,7 @@ let collect_all_summaries root_summaries_dir stacktrace_file stacktraces_dir =
     Utils.directory_fold
       (fun summaries path ->
          (* check if the file is a JSON file under the crashcontext dir *)
-         if (Sys.is_directory path) != `Yes && Filename.check_suffix path "json" &&
+         if (Sys.is_directory path) <> `Yes && Filename.check_suffix path "json" &&
             String.is_suffix ~suffix:"crashcontext" (Filename.dirname path)
          then path :: summaries
          else summaries)
diff --git a/infer/src/backend/dom.ml b/infer/src/backend/dom.ml
index 12e3bec1f..638f8aab0 100644
--- a/infer/src/backend/dom.ml
+++ b/infer/src/backend/dom.ml
@@ -1383,7 +1383,7 @@ let rec sigma_partial_join' tenv mode (sigma_acc: Prop.sigma)
      'todo' describes the start point. *)
 
   let cut_sigma side todo (target: Prop.sigma) (other: Prop.sigma) =
-    let list_is_empty l = if l != [] then (L.d_strln "failure reason 61"; raise IList.Fail) in
+    let list_is_empty l = if l <> [] then (L.d_strln "failure reason 61"; raise IList.Fail) in
     let x = Todo.take () in
     Todo.push todo;
     let res =
diff --git a/infer/src/backend/dotty.ml b/infer/src/backend/dotty.ml
index 523cdeeaa..a268da2dd 100644
--- a/infer/src/backend/dotty.ml
+++ b/infer/src/backend/dotty.ml
@@ -237,7 +237,7 @@ let color_to_str (c : Pp.color) =
 
 let make_dangling_boxes pe allocated_nodes (sigma_lambda: (Sil.hpred * int) list) =
   let exp_color hpred (exp : Exp.t) =
-    if pe.Pp.cmap_norm (Obj.repr hpred) == Pp.Red then Pp.Red
+    if pe.Pp.cmap_norm (Obj.repr hpred) = Pp.Red then Pp.Red
     else pe.Pp.cmap_norm (Obj.repr exp) in
   let get_rhs_predicate (hpred, lambda) =
     let n = !dotty_state_count in
@@ -322,7 +322,7 @@ let rec dotty_mk_node pe sigma =
   | [] -> []
   | (hpred, lambda) :: sigma' ->
       let exp_color (exp : Exp.t) =
-        if pe.Pp.cmap_norm (Obj.repr hpred) == Pp.Red then Pp.Red
+        if pe.Pp.cmap_norm (Obj.repr hpred) = Pp.Red then Pp.Red
         else pe.Pp.cmap_norm (Obj.repr exp) in
       do_hpred_lambda exp_color (hpred, lambda) @ dotty_mk_node pe sigma'
 
@@ -517,7 +517,7 @@ let rec dotty_mk_set_links dotnodes sigma p f cycle =
              try get_coordinate_id (IList.hd (IList.filter (is_source_node_of_exp e) nodes_e))
              with exn when SymOp.exn_not_failure exn -> assert false in
            (* we need to exclude the address node from the sorce of fields. no fields should start from there*)
-           let nl'= IList.filter (fun id -> address_struct_id != id) nl in
+           let nl'= IList.filter (fun id -> address_struct_id <> id) nl in
            let links_from_fields = IList.flatten (IList.map ff nl') in
            let lnk_from_address_struct = if !print_full_prop then
                let trg_label = strip_special_chars (Exp.to_string e) in
@@ -632,7 +632,7 @@ let filter_useless_spec_dollar_box (nodes: dotty_node list) (links: link list) =
   let remove_links_from ln = IList.filter (fun n' -> not (IList.mem Pervasives.(=) n' ln)) !tmp_links in
   let remove_node n ns =
     IList.filter (fun n' -> match n' with
-        | Dotpointsto _ -> (get_coordinate_id n')!= (get_coordinate_id n)
+        | Dotpointsto _ -> (get_coordinate_id n') <> (get_coordinate_id n)
         | _ -> true
       ) ns in
   let rec boxes_pointed_by n lns =
@@ -910,7 +910,7 @@ let dotty_prop_to_dotty_file fname prop cycle =
     let out_dot = open_out fname in
     let fmt_dot = Format.formatter_of_out_channel out_dot in
     pp_dotty_prop fmt_dot (prop, cycle);
-    close_out out_dot
+    Out_channel.close out_dot
   with exn when SymOp.exn_not_failure exn ->
     ()
 
@@ -927,7 +927,7 @@ let pp_proplist_parsed2dotty_file filename plist =
     let outc = open_out filename in
     let fmt = F.formatter_of_out_channel outc in
     F.fprintf fmt "#### Dotty version:  ####@.%a@.@." pp_list plist;
-    close_out outc
+    Out_channel.close outc
   with exn when SymOp.exn_not_failure exn ->
     ()
 
@@ -1027,7 +1027,7 @@ let write_icfg_dotty_to_file source cfg fname =
   F.fprintf fmt "/* @@%s */@\ndigraph iCFG {@\n" "generated";
   print_icfg source fmt cfg;
   F.fprintf fmt "}\n";
-  close_out chan
+  Out_channel.close chan
 
 let print_icfg_dotty source cfg =
   let fname =
@@ -1063,7 +1063,7 @@ let pp_speclist_to_file (filename : DB.filename) spec_list =
   let outc = open_out (DB.filename_to_string (DB.filename_add_suffix filename ".dot")) in
   let fmt = F.formatter_of_out_channel outc in
   let () = F.fprintf fmt "#### Dotty version:  ####@\n%a@\n@\n" (pp_speclist_dotty) spec_list in
-  close_out outc;
+  Out_channel.close outc;
   Config.pp_simple := pp_simple_saved
 
 let pp_speclist_dotty_file (filename : DB.filename) spec_list =
@@ -1277,7 +1277,7 @@ let prop_to_set_of_visual_heaps prop =
   let result = ref [] in
   working_list := [(!global_node_counter, prop.Prop.sigma)];
   incr global_node_counter;
-  while (!working_list!=[]) do
+  while (!working_list <> []) do
     set_dangling_nodes:=[];
     let (n, h) = IList.hd !working_list in
     working_list:= IList.tl !working_list;
diff --git a/infer/src/backend/errdesc.ml b/infer/src/backend/errdesc.ml
index 7860b92a3..efa593b43 100644
--- a/infer/src/backend/errdesc.ml
+++ b/infer/src/backend/errdesc.ml
@@ -142,7 +142,7 @@ let find_normal_variable_funcall
         Some (fun_exp, IList.map fst args, loc, call_flags)
     | _ -> None in
   let res = find_in_node_or_preds node find_declaration in
-  if verbose && res == None
+  if verbose && res = None
   then
     (L.d_str
        ("find_normal_variable_funcall could not find " ^
@@ -251,7 +251,7 @@ let rec _find_normal_variable_load tenv (seen : Exp.Set.t) node id : DExp.t opti
         Some (DExp.Dpvar pvar)
     | _ -> None in
   let res = find_in_node_or_preds node find_declaration in
-  if verbose && res == None
+  if verbose && res = None
   then
     (L.d_str
        ("find_normal_variable_load could not find " ^
@@ -560,7 +560,7 @@ let explain_leak tenv hpred prop alloc_att_opt bucket =
     | Some _ -> (* we know it has been allocated *)
         Exceptions.Exn_user, bucket
     | None ->
-        if leak_from_list_abstraction hpred prop && value_str != None
+        if leak_from_list_abstraction hpred prop && value_str <> None
         then
           (* we don't know it's been allocated,
              but it's coming from list abstraction and we have a name *)
diff --git a/infer/src/backend/exe_env.ml b/infer/src/backend/exe_env.ml
index 2fe164e25..36db88bfd 100644
--- a/infer/src/backend/exe_env.ml
+++ b/infer/src/backend/exe_env.ml
@@ -142,7 +142,7 @@ let get_source exe_env pname =
     (get_file_data exe_env pname)
 
 let file_data_to_tenv file_data =
-  if file_data.tenv == None
+  if file_data.tenv = None
   then file_data.tenv <- Tenv.load_from_file file_data.tenv_file;
   file_data.tenv
 
diff --git a/infer/src/backend/infer.ml b/infer/src/backend/infer.ml
index cad5074f9..92da57758 100644
--- a/infer/src/backend/infer.ml
+++ b/infer/src/backend/infer.ml
@@ -282,7 +282,7 @@ let analyze = function
       (* In Java and Javac modes, analysis is invoked from capture. *)
       ()
   | Analyze | Ant | Buck | ClangCompilationDatabase | Gradle | Genrule | Make | Mvn | Ndk | Xcode ->
-      if (Sys.file_exists Config.(results_dir // captured_dir_name)) != `Yes then (
+      if (Sys.file_exists Config.(results_dir // captured_dir_name)) <> `Yes then (
         L.stderr "There was nothing to analyze, exiting" ;
         Config.print_usage_exit ()
       );
@@ -309,7 +309,7 @@ let () =
   if Config.developer_mode then Printexc.record_backtrace true ;
   let build_cmd = IList.rev Config.rest in
   let build_mode = match build_cmd with path :: _ -> build_mode_of_string path | [] -> Analyze in
-  if build_mode != Analyze && not Config.buck && not Config.reactive_mode then
+  if build_mode <> Analyze && not Config.buck && not Config.reactive_mode then
     remove_results_dir () ;
   create_results_dir () ;
   (* re-set log files, as default files were in results_dir removed above *)
diff --git a/infer/src/backend/inferconfig.ml b/infer/src/backend/inferconfig.ml
index 0259a12b4..cdc319fb7 100644
--- a/infer/src/backend/inferconfig.ml
+++ b/infer/src/backend/inferconfig.ml
@@ -87,7 +87,7 @@ module FileContainsStringMatcher = struct
         try
           let file_in = open_in (SourceFile.to_abs_path source_file) in
           let pattern_found = file_contains regexp file_in in
-          close_in file_in;
+          In_channel.close file_in;
           source_map := SourceFile.Map.add source_file pattern_found !source_map;
           pattern_found
         with Sys_error _ -> false
diff --git a/infer/src/backend/interproc.ml b/infer/src/backend/interproc.ml
index e2ea23dff..5b84667c9 100644
--- a/infer/src/backend/interproc.ml
+++ b/infer/src/backend/interproc.ml
@@ -530,7 +530,7 @@ let forward_tabulate tenv pdesc wl source =
     let log_string proc_name =
       let summary = Specs.get_summary_unsafe "forward_tabulate" proc_name in
       let phase_string =
-        if Specs.get_phase summary == Specs.FOOTPRINT then "FP" else "RE" in
+        if Specs.get_phase summary = Specs.FOOTPRINT then "FP" else "RE" in
       let timestamp = Specs.get_timestamp summary in
       F.sprintf "[%s:%d] %s" phase_string timestamp (Procname.to_string proc_name) in
     L.d_strln ("**** " ^ (log_string pname) ^ " " ^
@@ -1236,7 +1236,7 @@ let update_specs tenv proc_name phase (new_specs : Specs.NormSpec.t list)
               (Paths.PathSet.from_renamed_list spec.Specs.posts, spec.Specs.visited) map)
          SpecMap.empty old_specs) in
   let re_exe_filter old_spec = (* filter out pres which failed re-exe *)
-    if phase == Specs.RE_EXECUTION &&
+    if phase = Specs.RE_EXECUTION &&
        not (IList.exists
               (fun new_spec -> Specs.Jprop.equal new_spec.Specs.pre old_spec.Specs.pre)
               new_specs)
@@ -1326,9 +1326,9 @@ let analyze_proc source exe_env proc_desc : Specs.summary =
   let prev_summary = Specs.get_summary_unsafe "analyze_proc" proc_name in
   let updated_summary =
     update_summary tenv prev_summary specs phase proc_name elapsed res in
-  if !Config.curr_language == Config.Clang && Config.report_custom_error then
+  if !Config.curr_language = Config.Clang && Config.report_custom_error then
     report_custom_errors tenv updated_summary;
-  if !Config.curr_language == Config.Java && Config.report_runtime_exceptions then
+  if !Config.curr_language = Config.Java && Config.report_runtime_exceptions then
     report_runtime_exceptions tenv proc_desc updated_summary;
   updated_summary
 
@@ -1396,7 +1396,7 @@ let perform_transition exe_env tenv proc_name source =
         [] in
     transition_footprint_re_exe tenv proc_name joined_pres in
   match Specs.get_summary proc_name with
-  | Some summary when Specs.get_phase summary == Specs.FOOTPRINT ->
+  | Some summary when Specs.get_phase summary = Specs.FOOTPRINT ->
       transition ()
   | _ -> ()
 
@@ -1531,7 +1531,7 @@ let print_stats_cfg proc_shadowed source cfg =
   let err_table = Errlog.create_err_table () in
   let filter pdesc =
     let pname = Procdesc.get_proc_name pdesc in
-    Specs.summary_exists pname && Specs.get_specs pname != [] in
+    Specs.summary_exists pname && Specs.get_specs pname <> [] in
   let nodes_visited, nodes_total = visited_and_total_nodes ~filter cfg in
   let num_proc = ref 0 in
   let num_nospec_noerror_proc = ref 0 in
@@ -1599,7 +1599,7 @@ let print_stats_cfg proc_shadowed source cfg =
       let outc = open_out (DB.filename_to_string stats_file) in
       let fmt = F.formatter_of_out_channel outc in
       print_file_stats fmt ();
-      close_out outc
+      Out_channel.close outc
     with Sys_error _ -> () in
   IList.iter compute_stats_proc (Cfg.get_defined_procs cfg);
   L.out "%a" print_file_stats ();
diff --git a/infer/src/backend/match.ml b/infer/src/backend/match.ml
index fa1455164..a08cf7797 100644
--- a/infer/src/backend/match.ml
+++ b/infer/src/backend/match.ml
@@ -424,7 +424,7 @@ and hpara_common_match_with_impl tenv impl_ok ids1 sigma1 eids2 ids2 sigma2 =
       (sub_eids, eids_fresh) in
     let sub = Sil.sub_of_list (sub_ids @ sub_eids) in
     match sigma2 with
-    | [] -> if sigma1 == [] then true else false
+    | [] -> if sigma1 = [] then true else false
     | hpred2 :: sigma2 ->
         let (hpat2, hpats2) =
           let (hpred2_ren, sigma2_ren) = (Sil.hpred_sub sub hpred2, Prop.sigma_sub sub sigma2) in
@@ -496,7 +496,7 @@ let rec generate_todos_from_strexp mode todos sexp1 sexp2 =
   | Sil.Eexp _, _ ->
       None
   | Sil.Estruct (fel1, _), Sil.Estruct (fel2, _) -> (* assume sorted w.r.t. fields *)
-      if (IList.length fel1 <> IList.length fel2) && mode == Exact
+      if (IList.length fel1 <> IList.length fel2) && mode = Exact
       then None
       else generate_todos_from_fel mode todos fel1 fel2
   | Sil.Estruct _, _ ->
@@ -513,9 +513,9 @@ and generate_todos_from_fel mode todos fel1 fel2 =
   | [], [] ->
       Some todos
   | [], _ ->
-      if mode == RFieldForget then Some todos else None
+      if mode = RFieldForget then Some todos else None
   | _, [] ->
-      if mode == LFieldForget then Some todos else None
+      if mode = LFieldForget then Some todos else None
   | (fld1, strexp1) :: fel1', (fld2, strexp2) :: fel2' ->
       let n = Ident.compare_fieldname fld1 fld2 in
       if (n = 0) then
@@ -524,9 +524,9 @@ and generate_todos_from_fel mode todos fel1 fel2 =
           | None -> None
           | Some todos' -> generate_todos_from_fel mode todos' fel1' fel2'
         end
-      else if (n < 0 && mode == LFieldForget) then
+      else if (n < 0 && mode = LFieldForget) then
         generate_todos_from_fel mode todos fel1' fel2
-      else if (n > 0 && mode == RFieldForget) then
+      else if (n > 0 && mode = RFieldForget) then
         generate_todos_from_fel mode todos fel1 fel2'
       else
         None
diff --git a/infer/src/backend/mergeCapture.ml b/infer/src/backend/mergeCapture.ml
index 5847fcc78..41b98859d 100644
--- a/infer/src/backend/mergeCapture.ml
+++ b/infer/src/backend/mergeCapture.ml
@@ -108,7 +108,7 @@ let rec slink ~stats ~skiplevels src dst =
   if Sys.is_directory src = `Yes
   then
     begin
-      if (Sys.file_exists dst) != `Yes
+      if (Sys.file_exists dst) <> `Yes
       then Unix.mkdir dst ~perm:0o700;
       let items = Sys.readdir src in
       Array.iter
diff --git a/infer/src/backend/paths.ml b/infer/src/backend/paths.ml
index 614b86a57..fc6d0d4c5 100644
--- a/infer/src/backend/paths.ml
+++ b/infer/src/backend/paths.ml
@@ -150,7 +150,7 @@ end = struct
   module Invariant = struct
     (** check whether a stats is the dummy stats *)
     let stats_is_dummy stats =
-      stats.max_length == - 1
+      stats.max_length = - 1
 
     (** return the stats of the path, assumes that the stats are computed *)
     let get_stats = function
@@ -422,7 +422,7 @@ end = struct
   let rec contains p1 p2 = match p2 with
     | Pjoin (p2', p2'', _) ->
         contains p1 p2' || contains p1 p2''
-    | _ -> p1 == p2
+    | _ -> phys_equal p1 p2
 
   let create_loc_trace path pos_opt : Errlog.loc_trace =
     let trace = ref [] in
diff --git a/infer/src/backend/preanal.ml b/infer/src/backend/preanal.ml
index 47de66ccc..d0e2e657e 100644
--- a/infer/src/backend/preanal.ml
+++ b/infer/src/backend/preanal.ml
@@ -133,7 +133,7 @@ module NullifyTransferFunctions = struct
       match IList.rev instrs with
       | instr :: _ -> instr
       | [] -> Sil.skip_instr in
-    if node == !cache_node
+    if phys_equal node !cache_node
     then !cache_instr
     else
       begin
@@ -144,7 +144,7 @@ module NullifyTransferFunctions = struct
       end
 
   let is_last_instr_in_node instr node =
-    last_instr_in_node node == instr
+    phys_equal (last_instr_in_node node) instr
 
   let exec_instr ((active_defs, to_nullify) as astate) extras node instr =
     let astate' = match instr with
@@ -188,7 +188,7 @@ let remove_dead_frontend_stores pdesc liveness_inv_map =
   let node_remove_dead_stores node =
     let instr_nodes = BackwardCfg.instr_ids node in
     let instr_nodes' = IList.filter_changed is_used_store instr_nodes in
-    if instr_nodes' != instr_nodes
+    if not (phys_equal instr_nodes' instr_nodes)
     then
       Procdesc.Node.replace_instrs node (IList.rev_map fst instr_nodes') in
   Procdesc.iter_nodes node_remove_dead_stores pdesc
@@ -285,7 +285,7 @@ let do_copy_propagation pdesc tenv =
                match CopyProp.extract_pre id copy_prop_inv_map with
                | Some pre when not (CopyPropagation.Domain.is_empty pre) ->
                    let instr' = Sil.instr_sub_ids ~sub_id_binders:false (id_sub pre) instr in
-                   instr' :: instrs, changed || instr' != instr
+                   instr' :: instrs, changed || not (phys_equal instr' instr)
                | _ ->
                    instr :: instrs, changed
              end
diff --git a/infer/src/backend/printer.ml b/infer/src/backend/printer.ml
index 75fc0933c..679f795da 100644
--- a/infer/src/backend/printer.ml
+++ b/infer/src/backend/printer.ml
@@ -41,7 +41,7 @@ struct
       done;
       assert false (* execution never reaches here *)
     with End_of_file ->
-      (close_in cin;
+      (In_channel.close cin;
        Array.of_list (IList.rev !lines))
 
   let file_data (hash: t) fname =
@@ -399,7 +399,7 @@ let node_start_session node loc proc_name session source =
 
 (** Finish a session, and perform delayed print actions if required *)
 let node_finish_session node source =
-  if Config.test == false then force_delayed_prints ()
+  if Config.test = false then force_delayed_prints ()
   else L.reset_delayed_prints ();
   if Config.write_html then begin
     F.fprintf !curr_html_formatter "</LISTING>%a"
diff --git a/infer/src/backend/prop.ml b/infer/src/backend/prop.ml
index a79048e61..d21641dc1 100644
--- a/infer/src/backend/prop.ml
+++ b/infer/src/backend/prop.ml
@@ -124,9 +124,9 @@ let equal_prop p1 p2 =
 let pp_footprint _pe f fp =
   let pe = { _pe with Pp.cmap_norm = _pe.Pp.cmap_foot } in
   let pp_pi f () =
-    if fp.pi_fp != [] then
+    if fp.pi_fp <> [] then
       F.fprintf f "%a ;@\n" (Pp.semicolon_seq_oneline pe (Sil.pp_atom pe)) fp.pi_fp in
-  if fp.pi_fp != [] || fp.sigma_fp != [] then
+  if fp.pi_fp <> [] || fp.sigma_fp <> [] then
     F.fprintf f "@\n[footprint@\n  @[%a%a@]  ]"
       pp_pi () (Pp.semicolon_seq pe (Sil.pp_hpred pe)) fp.sigma_fp
 
@@ -203,23 +203,23 @@ let pp_sigma_simple pe env fmt sigma =
   let sigma_stack, sigma_nonstack = sigma_get_stack_nonstack false sigma in
   let pp_stack fmt _sg =
     let sg = IList.sort Sil.compare_hpred _sg in
-    if sg != [] then Format.fprintf fmt "%a" (Pp.semicolon_seq pe (pp_hpred_stackvar pe)) sg in
+    if sg <> [] then Format.fprintf fmt "%a" (Pp.semicolon_seq pe (pp_hpred_stackvar pe)) sg in
   let pp_nl fmt doit = if doit then
       (match pe.Pp.kind with
        | TEXT | HTML -> Format.fprintf fmt " ;@\n"
        | LATEX -> Format.fprintf fmt " ; \\\\@\n") in
   let pp_nonstack fmt = Pp.semicolon_seq pe (Sil.pp_hpred_env pe (Some env)) fmt in
-  if sigma_stack != [] || sigma_nonstack != [] then
+  if sigma_stack <> [] || sigma_nonstack <> [] then
     Format.fprintf fmt "%a%a%a"
       pp_stack sigma_stack pp_nl
-      (sigma_stack != [] && sigma_nonstack != []) pp_nonstack sigma_nonstack
+      (sigma_stack <> [] && sigma_nonstack <> []) pp_nonstack sigma_nonstack
 
 (** Dump a sigma. *)
 let d_sigma (sigma: sigma) = L.add_print_action (PTsigma, Obj.repr sigma)
 
 (** Dump a pi and a sigma *)
 let d_pi_sigma pi sigma =
-  let d_separator () = if pi != [] && sigma != [] then L.d_strln " *" in
+  let d_separator () = if pi <> [] && sigma <> [] then L.d_strln " *" in
   d_pi pi; d_separator (); d_sigma sigma
 
 let pi_of_subst sub =
@@ -231,7 +231,7 @@ let get_pure (p: 'a t) : pi =
 
 (** Print existential quantification *)
 let pp_evars pe f evars =
-  if evars != []
+  if evars <> []
   then match pe.Pp.kind with
     | TEXT | HTML ->
         F.fprintf f "exists [%a]. " (Pp.comma_seq (Ident.pp pe)) evars
@@ -288,9 +288,9 @@ let prop_update_obj_sub pe prop =
 let pp_footprint_simple _pe env f fp =
   let pe = { _pe with Pp.cmap_norm = _pe.Pp.cmap_foot } in
   let pp_pure f pi =
-    if pi != [] then
+    if pi <> [] then
       F.fprintf f "%a *@\n" (pp_pi pe) pi in
-  if fp.pi_fp != [] || fp.sigma_fp != [] then
+  if fp.pi_fp <> [] || fp.sigma_fp <> [] then
     F.fprintf f "@\n[footprint@\n   @[%a%a@]  ]"
       pp_pure fp.pi_fp
       (pp_sigma_simple pe env) fp.sigma_fp
@@ -305,14 +305,14 @@ let prop_pred_env prop =
 (** Pretty print a proposition. *)
 let pp_prop pe0 f prop =
   let pe = prop_update_obj_sub pe0 prop in
-  let latex = pe.Pp.kind == Pp.LATEX in
+  let latex = pe.Pp.kind = Pp.LATEX in
   let do_print f () =
     let subl = Sil.sub_to_list prop.sub in
     (* since prop diff is based on physical equality, we need to extract the sub verbatim *)
     let pi = prop.pi in
     let pp_pure f () =
-      if subl != [] then F.fprintf f "%a ;@\n" (pp_subl pe) subl;
-      if pi != [] then F.fprintf f "%a ;@\n" (pp_pi pe) pi in
+      if subl <> [] then F.fprintf f "%a ;@\n" (pp_subl pe) subl;
+      if pi <> [] then F.fprintf f "%a ;@\n" (pp_pi pe) pi in
     if !Config.pp_simple || latex then
       begin
         let env = prop_pred_env prop in
@@ -2117,7 +2117,7 @@ let prop_ren_sub tenv (ren_sub: Sil.subst) (prop: normal t) : normal t =
 let exist_quantify tenv fav (prop : normal t) : normal t =
   let ids = Sil.fav_to_list fav in
   if IList.exists Ident.is_primed ids then assert false; (* sanity check *)
-  if ids == [] then prop else
+  if ids = [] then prop else
     let gen_fresh_id_sub id = (id, Exp.Var (Ident.create_fresh Ident.kprimed)) in
     let ren_sub = Sil.sub_of_list (IList.map gen_fresh_id_sub ids) in
     let prop' =
diff --git a/infer/src/backend/propgraph.ml b/infer/src/backend/propgraph.ml
index 143a835de..0fb2a0d95 100644
--- a/infer/src/backend/propgraph.ml
+++ b/infer/src/backend/propgraph.ml
@@ -193,7 +193,7 @@ let compute_diff default_color oldgraph newgraph : diff =
             () in
     IList.iter build_changed newedges;
     let colormap (o: Obj.t) =
-      if IList.exists (fun x -> x == o) !changed then Pp.Red
+      if IList.exists (fun x -> phys_equal x o) !changed then Pp.Red
       else default_color in
     !changed, colormap in
   let changed_norm, colormap_norm = compute_changed false in
diff --git a/infer/src/backend/prover.ml b/infer/src/backend/prover.ml
index b75b38868..61a5952f5 100644
--- a/infer/src/backend/prover.ml
+++ b/infer/src/backend/prover.ml
@@ -484,7 +484,7 @@ end = struct
           IList.map (function
               | _, Exp.Const (Const.Cint n) -> n
               | _ -> assert false) e_upper_list in
-        if upper_list == [] then None
+        if upper_list = [] then None
         else Some (compute_min_from_nonempty_int_list upper_list)
 
   (** Find a IntLit.t n such that [t |- n < e] if possible. *)
@@ -501,7 +501,7 @@ end = struct
           IList.map (function
               | Exp.Const (Const.Cint n), _ -> n
               | _ -> assert false) e_lower_list in
-        if lower_list == [] then None
+        if lower_list = [] then None
         else Some (compute_max_from_nonempty_int_list lower_list)
 
   (** Return [true] if a simple inconsistency is detected *)
@@ -651,7 +651,7 @@ let check_disequal tenv prop e1 e2 =
                let sigma_irrelevant' = hpred :: sigma_irrelevant
                in f sigma_irrelevant' e sigma_rest
            | Some _ ->
-               if (k == Sil.Lseg_NE || check_pi_implies_disequal e1 e2) then
+               if (k = Sil.Lseg_NE || check_pi_implies_disequal e1 e2) then
                  let sigma_irrelevant' = (IList.rev sigma_irrelevant) @ sigma_rest
                  in Some (true, sigma_irrelevant')
                else if (Exp.equal e2 Exp.zero) then
@@ -661,7 +661,7 @@ let check_disequal tenv prop e1 e2 =
                  let sigma_rest' = (IList.rev sigma_irrelevant) @ sigma_rest
                  in f [] e2 sigma_rest')
       | Sil.Hdllseg (Sil.Lseg_NE, _, iF, _, _, iB, _) :: sigma_rest ->
-          if is_root tenv prop iF e != None || is_root tenv prop iB e != None then
+          if is_root tenv prop iF e <> None || is_root tenv prop iB e <> None then
             let sigma_irrelevant' = (IList.rev sigma_irrelevant) @ sigma_rest
             in Some (true, sigma_irrelevant')
           else
@@ -737,7 +737,7 @@ let get_smt_key a p =
   let outc_tmp = open_out tmp_filename in
   let fmt_tmp = F.formatter_of_out_channel outc_tmp in
   let () = F.fprintf fmt_tmp "%a%a" (Sil.pp_atom Pp.text) a (Prop.pp_prop Pp.text) p in
-  close_out outc_tmp;
+  Out_channel.close outc_tmp;
   Digest.to_hex (Digest.file tmp_filename)
 
 (** Check whether [prop |- a]. False means dont know. *)
@@ -758,7 +758,7 @@ let check_atom tenv prop a0 =
     L.d_str "WHERE:"; L.d_ln(); Prop.d_prop prop_no_fp; L.d_ln (); L.d_ln ();
     F.fprintf fmt "ID: %s @\nCHECK_ATOM_BOUND: %a@\nWHERE:@\n%a"
       key (Sil.pp_atom Pp.text) a (Prop.pp_prop Pp.text) prop_no_fp;
-    close_out outc;
+    Out_channel.close outc;
   end;
   match a with
   | Sil.Aeq (Exp.BinOp (Binop.Le, e1, e2), Exp.Const (Const.Cint i))
@@ -780,14 +780,14 @@ let check_allocatedness tenv prop e =
   let spatial_part = prop.Prop.sigma in
   let f = function
     | Sil.Hpointsto (base, _, _) ->
-        is_root tenv prop base n_e != None
+        is_root tenv prop base n_e <> None
     | Sil.Hlseg (k, _, e1, e2, _) ->
-        if k == Sil.Lseg_NE || check_disequal tenv prop e1 e2 then
-          is_root tenv prop e1 n_e != None
+        if k = Sil.Lseg_NE || check_disequal tenv prop e1 e2 then
+          is_root tenv prop e1 n_e <> None
         else false
     | Sil.Hdllseg (k, _, iF, oB, oF, iB, _) ->
-        if k == Sil.Lseg_NE || check_disequal tenv prop iF oF || check_disequal tenv prop iB oB then
-          is_root tenv prop iF n_e != None || is_root tenv prop iB n_e != None
+        if k = Sil.Lseg_NE || check_disequal tenv prop iF oF || check_disequal tenv prop iB oB then
+          is_root tenv prop iF n_e <> None || is_root tenv prop iB n_e <> None
         else false
   in IList.exists f spatial_part
 
@@ -1047,25 +1047,25 @@ end = struct
   let _d_missing sub =
     L.d_strln "SUB: ";
     L.d_increase_indent 1; Prop.d_sub sub; L.d_decrease_indent 1;
-    if !missing_pi != [] && !missing_sigma != []
+    if !missing_pi <> [] && !missing_sigma <> []
     then (L.d_ln (); Prop.d_pi !missing_pi; L.d_str "*"; L.d_ln (); Prop.d_sigma !missing_sigma)
-    else if !missing_pi != []
+    else if !missing_pi <> []
     then (L.d_ln (); Prop.d_pi !missing_pi)
-    else if !missing_sigma != []
+    else if !missing_sigma <> []
     then (L.d_ln (); Prop.d_sigma !missing_sigma);
-    if !missing_fld != [] then
+    if !missing_fld <> [] then
       begin
         L.d_ln ();
         L.d_strln "MISSING FLD: "; L.d_increase_indent 1; Prop.d_sigma !missing_fld; L.d_decrease_indent 1
       end;
-    if !missing_typ != [] then
+    if !missing_typ <> [] then
       begin
         L.d_ln ();
         L.d_strln "MISSING TYPING: "; L.d_increase_indent 1; d_typings !missing_typ; L.d_decrease_indent 1
       end
 
   let d_missing sub = (* optional print of missing: if print something, prepend with newline *)
-    if !missing_pi != [] || !missing_sigma!=[] || !missing_fld != [] || !missing_typ != [] || Sil.sub_to_list sub != [] then
+    if !missing_pi <> [] || !missing_sigma <> [] || !missing_fld <> [] || !missing_typ <> [] || Sil.sub_to_list sub <> [] then
       begin
         L.d_ln ();
         L.d_str "[";
@@ -1074,7 +1074,7 @@ end = struct
       end
 
   let d_frame_fld () = (* optional print of frame fld: if print something, prepend with newline *)
-    if !frame_fld != [] then
+    if !frame_fld <> [] then
       begin
         L.d_ln ();
         L.d_strln "[FRAME FLD:";
@@ -1082,7 +1082,7 @@ end = struct
       end
 
   let d_frame_typ () = (* optional print of frame typ: if print something, prepend with newline *)
-    if !frame_typ != [] then
+    if !frame_typ <> [] then
       begin
         L.d_ln ();
         L.d_strln "[FRAME TYPING:";
@@ -1202,7 +1202,7 @@ let exp_imply tenv calc_missing subs e1_in e2_in : subst2 =
         raise (IMPL_EXC ("pointer+index cannot evaluate to a constant", subs, (EXC_FALSE_EXPS (e1, e2))))
     | Exp.Const (Const.Cint n1), Exp.BinOp (Binop.PlusA, f1, Exp.Const (Const.Cint n2)) ->
         do_imply subs (Exp.int (n1 -- n2)) f1
-    | Exp.BinOp(op1, e1, f1), Exp.BinOp(op2, e2, f2) when op1 == op2 ->
+    | Exp.BinOp(op1, e1, f1), Exp.BinOp(op2, e2, f2) when op1 = op2 ->
         do_imply (do_imply subs e1 e2) f1 f2
     | Exp.BinOp (Binop.PlusA, Exp.Var v1, e1), e2 ->
         do_imply subs (Exp.Var v1) (Exp.BinOp (Binop.MinusA, e2, e1))
@@ -1218,7 +1218,7 @@ let exp_imply tenv calc_missing subs e1_in e2_in : subst2 =
         raise (IMPL_EXC ("expressions not equal", subs, (EXC_FALSE_EXPS (e1, e2))))
     | e1, Exp.Const _ ->
         raise (IMPL_EXC ("lhs not constant", subs, (EXC_FALSE_EXPS (e1, e2))))
-    | Exp.Lfield(e1, fd1, _), Exp.Lfield(e2, fd2, _) when fd1 == fd2 ->
+    | Exp.Lfield(e1, fd1, _), Exp.Lfield(e2, fd2, _) when Ident.equal_fieldname fd1 fd2 ->
         do_imply subs e1 e2
     | Exp.Lindex(e1, f1), Exp.Lindex(e2, f2) ->
         do_imply (do_imply subs e1 e2) f1 f2
@@ -1284,8 +1284,8 @@ let rec sexp_imply tenv source calc_index_frame calc_missing subs se1 se2 typ2 :
       (exp_imply tenv calc_missing subs e1 e2, None, None)
   | Sil.Estruct (fsel1, inst1), Sil.Estruct (fsel2, _) ->
       let subs', fld_frame, fld_missing = struct_imply tenv source calc_missing subs fsel1 fsel2 typ2 in
-      let fld_frame_opt = if fld_frame != [] then Some (Sil.Estruct (fld_frame, inst1)) else None in
-      let fld_missing_opt = if fld_missing != [] then Some (Sil.Estruct (fld_missing, inst1)) else None in
+      let fld_frame_opt = if fld_frame <> [] then Some (Sil.Estruct (fld_frame, inst1)) else None in
+      let fld_missing_opt = if fld_missing <> [] then Some (Sil.Estruct (fld_missing, inst1)) else None in
       subs', fld_frame_opt, fld_missing_opt
   | Sil.Estruct _, Sil.Eexp (e2, _) ->
       begin
@@ -1304,11 +1304,11 @@ let rec sexp_imply tenv source calc_index_frame calc_missing subs se1 se2 typ2 :
       let subs' = array_len_imply tenv calc_missing subs len1 len2 indices2 in
       let subs'', index_frame, index_missing =
         array_imply tenv source calc_index_frame calc_missing subs' esel1 esel2 typ2 in
-      let index_frame_opt = if index_frame != []
+      let index_frame_opt = if index_frame <> []
         then Some (Sil.Earray (len1, index_frame, inst1))
         else None in
       let index_missing_opt =
-        if index_missing != [] &&
+        if index_missing <> [] &&
            (Config.allow_missing_index_in_proc_call || !Config.footprint)
         then Some (Sil.Earray (len1, index_missing, inst1))
         else None in
@@ -1846,7 +1846,7 @@ let rec hpred_imply tenv calc_index_frame calc_missing subs prop1 sigma2 hpred2
                raise (Exceptions.Abduction_case_not_implemented __POS__))
         | _ -> ()
       in
-      if Exp.equal e2 f2 && k == Sil.Lseg_PE then (subs, prop1)
+      if Exp.equal e2 f2 && k = Sil.Lseg_PE then (subs, prop1)
       else
         (match Prop.prop_iter_create prop1 with
          | None -> raise (IMPL_EXC ("lhs is empty", subs, EXC_FALSE))
@@ -2149,7 +2149,7 @@ let check_implication_base pname tenv check_frame_empty calc_missing prop1 prop2
     L.d_increase_indent 1; Prop.d_pi pi1; L.d_decrease_indent 1; L.d_ln ();
     L.d_strln "pi2:";
     L.d_increase_indent 1; Prop.d_pi pi2; L.d_decrease_indent 1; L.d_ln ();
-    if pi2_bcheck != []
+    if pi2_bcheck <> []
     then (L.d_str "pi2 bounds checks: "; Prop.d_pi pi2_bcheck; L.d_ln ());
     L.d_strln "returns";
     L.d_strln "sub1: ";
@@ -2169,7 +2169,7 @@ let check_implication_base pname tenv check_frame_empty calc_missing prop1 prop2
     L.d_increase_indent 1; d_impl (sub1, sub2) (prop1, prop2); L.d_decrease_indent 1; L.d_ln ();
     L.d_strln"returning TRUE";
     let frame = frame_prop.Prop.sigma in
-    if check_frame_empty && frame != [] then raise (IMPL_EXC("frame not empty", subs, EXC_FALSE));
+    if check_frame_empty && frame <> [] then raise (IMPL_EXC("frame not empty", subs, EXC_FALSE));
     Some ((sub1, sub2), frame)
   with
   | IMPL_EXC (s, subs, body) ->
diff --git a/infer/src/backend/rearrange.ml b/infer/src/backend/rearrange.ml
index e9c4a8090..e832c7152 100644
--- a/infer/src/backend/rearrange.ml
+++ b/infer/src/backend/rearrange.ml
@@ -294,7 +294,7 @@ and array_case_analysis_index pname tenv orig_prop
     index off inst_arr inst
   =
   let check_sound t' =
-    if not (Typ.equal typ_cont t' || array_cont == [])
+    if not (Typ.equal typ_cont t' || array_cont = [])
     then raise (Exceptions.Bad_footprint __POS__) in
   let index_in_array =
     IList.exists (fun (i, _) -> Prover.check_equal tenv Prop.prop_emp index i) array_cont in
diff --git a/infer/src/backend/specs.ml b/infer/src/backend/specs.ml
index a8f494188..731b3ccf8 100644
--- a/infer/src/backend/specs.ml
+++ b/infer/src/backend/specs.ml
@@ -36,7 +36,7 @@ module Jprop = struct
 
   (** Return true if the two join_prop's are equal *)
   let equal jp1 jp2 =
-    compare jp1 jp2 == 0
+    compare jp1 jp2 = 0
 
   let to_prop = function
     | Prop (_, p) -> p
@@ -408,10 +408,10 @@ let describe_timestamp summary =
   ("Timestamp", Printf.sprintf "%d" summary.timestamp)
 
 let describe_status summary =
-  ("Status", if summary.status == ACTIVE then "ACTIVE" else "INACTIVE")
+  ("Status", if summary.status = ACTIVE then "ACTIVE" else "INACTIVE")
 
 let describe_phase summary =
-  ("Phase", if summary.phase == FOOTPRINT then "FOOTPRINT" else "RE_EXECUTION")
+  ("Phase", if summary.phase = FOOTPRINT then "FOOTPRINT" else "RE_EXECUTION")
 
 (** Return the signature of a procedure declaration as a string *)
 let get_signature summary =
diff --git a/infer/src/backend/state.ml b/infer/src/backend/state.ml
index 0713439d8..fd78f5d3a 100644
--- a/infer/src/backend/state.ml
+++ b/infer/src/backend/state.ml
@@ -151,7 +151,7 @@ let instrs_normalize instrs =
       | _ -> ids in
     IList.fold_left do_instr [] instrs in
   let subst =
-    let count = ref min_int in
+    let count = ref Int.min_value in
     let gensym id =
       incr count;
       Ident.set_stamp id !count in
diff --git a/infer/src/backend/symExec.ml b/infer/src/backend/symExec.ml
index e42c89dfc..3177b0752 100644
--- a/infer/src/backend/symExec.ml
+++ b/infer/src/backend/symExec.ml
@@ -381,7 +381,7 @@ let call_should_be_skipped callee_summary =
   (* skip abstract methods *)
   || callee_summary.Specs.attributes.ProcAttributes.is_abstract
   (* treat calls with no specs as skip functions in angelic mode *)
-  || (Config.angelic_execution && Specs.get_specs_from_payload callee_summary == [])
+  || (Config.angelic_execution && Specs.get_specs_from_payload callee_summary = [])
 
 (** In case of constant string dereference, return the result immediately *)
 let check_constant_string_dereference lexp =
diff --git a/infer/src/backend/tabulation.ml b/infer/src/backend/tabulation.ml
index b6550c28f..5c98d7d72 100644
--- a/infer/src/backend/tabulation.ml
+++ b/infer/src/backend/tabulation.ml
@@ -123,7 +123,7 @@ let spec_find_rename trace_call (proc_name : Procname.t)
     let f spec =
       incr count; (!count, spec_rename_vars proc_name spec) in
     let specs, formals = Specs.get_specs_formals proc_name in
-    if specs == [] then
+    if specs = [] then
       begin
         trace_call Specs.CallStats.CR_not_found;
         raise (Exceptions.Precondition_not_found
@@ -303,7 +303,7 @@ let check_dereferences tenv callee_pname actual_pre sub spec_pre formal_params =
         | Some (_, pos) -> Some pos
         | None -> None
       else None in
-    if deref_no_null_check_pos != None
+    if deref_no_null_check_pos <> None
     then
       (* only report a dereference null error if we know
          there was a dereference without null check *)
@@ -854,7 +854,7 @@ let mk_actual_precondition tenv prop actual_params formal_params =
     let rec comb fpars apars = match fpars, apars with
       | f:: fpars', a:: apars' -> (f, a) :: comb fpars' apars'
       | [], _ ->
-          if apars != [] then
+          if apars <> [] then
             begin
               let str =
                 "more actual pars than formal pars in fun call (" ^
@@ -1078,12 +1078,12 @@ let exe_spec
             (* missing fields minus hidden fields *)
             let missing_fld_nohidden =
               IList.filter (fun hp -> not (hpred_missing_hidden hp)) missing_fld in
-            if !Config.footprint = false && split.missing_sigma != [] then
+            if !Config.footprint = false && split.missing_sigma <> [] then
               begin
                 L.d_strln "Implication error: missing_sigma not empty in re-execution";
                 Invalid_res Missing_sigma_not_empty
               end
-            else if !Config.footprint = false && missing_fld_nohidden != [] then
+            else if !Config.footprint = false && missing_fld_nohidden <> [] then
               begin
                 L.d_strln "Implication error: missing_fld not empty in re-execution";
                 Invalid_res Missing_fld_not_empty
@@ -1117,7 +1117,7 @@ let prop_pure_to_footprint tenv (p: 'a Prop.t) : Prop.normal Prop.t =
     Sil.fav_for_all a_fav Ident.is_footprint in
   let pure = Prop.get_pure p in
   let new_footprint_atoms = IList.filter is_footprint_atom_not_attribute pure in
-  if new_footprint_atoms == []
+  if new_footprint_atoms = []
   then p
   else (* add pure fact to footprint *)
     Prop.normalize tenv (Prop.set p ~pi_fp:(p.Prop.pi_fp @ new_footprint_atoms))
@@ -1134,7 +1134,7 @@ let exe_call_postprocess tenv ret_id trace_call callee_pname callee_attrs loc re
   let invalid_res =
     IList.map (function Valid_res _ -> assert false | Invalid_res ir -> ir) invalid_res0 in
   let valid_res_miss_pi, valid_res_no_miss_pi =
-    IList.partition (fun vr -> vr.vr_pi != []) valid_res in
+    IList.partition (fun vr -> vr.vr_pi <> []) valid_res in
   let _, valid_res_cons_pre_missing =
     IList.partition (fun vr -> vr.incons_pre_missing) valid_res in
   let deref_errors = IList.filter (function Dereference_error _ -> true | _ -> false) invalid_res in
@@ -1144,7 +1144,7 @@ let exe_call_postprocess tenv ret_id trace_call callee_pname callee_attrs loc re
   let res_with_path_idents =
     if !Config.footprint then
       begin
-        if valid_res_cons_pre_missing == [] then
+        if valid_res_cons_pre_missing = [] then
           (* no valid results where actual pre and missing are consistent *)
           begin
             if deref_errors <> [] then (* dereference error detected *)
@@ -1222,9 +1222,9 @@ let exe_call_postprocess tenv ret_id trace_call callee_pname callee_attrs loc re
             (fun (p, path) -> (prop_pure_to_footprint tenv p, path))
             (IList.flatten (IList.map process_valid_res valid_res))
       end
-    else if valid_res_no_miss_pi != [] then
+    else if valid_res_no_miss_pi <> [] then
       IList.flatten (IList.map (fun vr -> vr.vr_cons_res) valid_res_no_miss_pi)
-    else if valid_res_miss_pi == [] then
+    else if valid_res_miss_pi = [] then
       raise (Exceptions.Precondition_not_met (call_desc None, __POS__))
     else
       begin
diff --git a/infer/src/base/Config.ml b/infer/src/base/Config.ml
index 099250c49..dd87c4347 100644
--- a/infer/src/base/Config.ml
+++ b/infer/src/base/Config.ml
@@ -1117,7 +1117,7 @@ and progress_bar =
     "Show a progress bar"
 
 and quiet =
-  CLOpt.mk_bool ~long:"quiet" ~short:"q" ~default:(current_exe != CLOpt.Print)
+  CLOpt.mk_bool ~long:"quiet" ~short:"q" ~default:(current_exe <> CLOpt.Print)
     ~exes:CLOpt.[Print]
     "Do not print specs on standard output"
 
diff --git a/infer/src/base/DB.ml b/infer/src/base/DB.ml
index 4085f2c66..21abe8922 100644
--- a/infer/src/base/DB.ml
+++ b/infer/src/base/DB.ml
@@ -92,7 +92,7 @@ let file_modified_time ?(symlink=false) fname =
 
 let filename_create_dir fname =
   let dirname = Filename.dirname fname in
-  if (Sys.file_exists dirname) != `Yes
+  if (Sys.file_exists dirname) <> `Yes
   then Utils.create_dir dirname
 
 let read_whole_file fd =
@@ -161,7 +161,7 @@ module Results_dir = struct
     let rec f = function
       | [] -> base
       | name:: names ->
-          Filename.concat (f names) (if name ==".." then Filename.parent_dir_name else name) in
+          Filename.concat (f names) (if String.equal name ".." then Filename.parent_dir_name else name) in
     f (IList.rev path)
 
   (** convert a path to a filename *)
diff --git a/infer/src/base/Latex.ml b/infer/src/base/Latex.ml
index a610b6dc7..5aa9e4c8f 100644
--- a/infer/src/base/Latex.ml
+++ b/infer/src/base/Latex.ml
@@ -25,7 +25,7 @@ let convert_string s =
     let cnt = ref 0 in
     let s' = ref "" in
     let f c =
-      if c == '_' then s' := !s' ^ "\\_"
+      if c = '_' then s' := !s' ^ "\\_"
       else s' := !s' ^ Char.escaped (String.get s !cnt);
       incr cnt in
     String.iter ~f s;
diff --git a/infer/src/base/Logging.ml b/infer/src/base/Logging.ml
index 4392da2a4..c2375efa4 100644
--- a/infer/src/base/Logging.ml
+++ b/infer/src/base/Logging.ml
@@ -70,7 +70,7 @@ let set_log_file_identifier (current_exe : CLOpt.exe) string_opt =
           if Lazy.is_val fmt_chan_file then (
             let (fmt, chan, _) = Lazy.force fmt_chan_file in
             F.pp_print_flush fmt () ;
-            Pervasives.close_out_noerr chan
+            Out_channel.close chan
           ) in
         close out_fmt_chan_file ;
         close err_fmt_chan_file
diff --git a/infer/src/base/Multilinks.re b/infer/src/base/Multilinks.re
index fd2664865..85ebfca3a 100644
--- a/infer/src/base/Multilinks.re
+++ b/infer/src/base/Multilinks.re
@@ -42,7 +42,7 @@ let write multilinks dir::dir => {
   let fname = Filename.concat dir multilink_file_name;
   let outc = open_out fname;
   String.Table.iteri f::(fun key::_ data::src => output_string outc (src ^ "\n")) multilinks;
-  close_out outc
+  Out_channel.close outc
 };
 
 let lookup dir::dir =>
diff --git a/infer/src/base/Pp.ml b/infer/src/base/Pp.ml
index adf63e491..877984a0c 100644
--- a/infer/src/base/Pp.ml
+++ b/infer/src/base/Pp.ml
@@ -73,7 +73,7 @@ let latex color =
 (** Extend the normal colormap for the given object with the given color *)
 let extend_colormap pe (x: Obj.t) (c: color) =
   let colormap (y: Obj.t) =
-    if x == y then c
+    if phys_equal x y then c
     else pe.cmap_norm y in
   { pe with cmap_norm = colormap }
 
diff --git a/infer/src/base/Serialization.ml b/infer/src/base/Serialization.ml
index 033e4ca73..c5d03e089 100644
--- a/infer/src/base/Serialization.ml
+++ b/infer/src/base/Serialization.ml
@@ -67,7 +67,7 @@ let create_serializer (key : key) : 'a serializer =
     | inc ->
         let read () =
           try
-            seek_in inc 0 ;
+            In_channel.seek inc 0L ;
             match_data (Marshal.from_channel inc) fname
           with
           | Sys_error _ -> None in
@@ -80,7 +80,7 @@ let create_serializer (key : key) : 'a serializer =
         (* which indicates that another process is writing the same file. *)
         SymOp.try_finally
           (fun () -> retry_exception timeout catch_exn read ())
-          (fun () -> close_in inc) in
+          (fun () -> In_channel.close inc) in
   let to_file (fname : DB.filename) (value : 'a) =
     let fname_str = DB.filename_to_string fname in
     (* support nonblocking reads and writes in parallel: *)
@@ -89,7 +89,7 @@ let create_serializer (key : key) : 'a serializer =
         ~in_dir:(Filename.dirname fname_str) (Filename.basename fname_str) ".tmp" in
     let outc = open_out_bin fname_tmp in
     Marshal.to_channel outc (key, version, value) [];
-    close_out outc;
+    Out_channel.close outc;
     Unix.rename ~src:fname_tmp ~dst:fname_str in
   (from_string, from_file, to_file)
 
diff --git a/infer/src/base/Utils.ml b/infer/src/base/Utils.ml
index 6b7340646..18bcc271b 100644
--- a/infer/src/base/Utils.ml
+++ b/infer/src/base/Utils.ml
@@ -25,7 +25,7 @@ let read_file fname =
   let cleanup () =
     match !cin_ref with
     | None -> ()
-    | Some cin -> close_in cin in
+    | Some cin -> In_channel.close cin in
   try
     let cin = open_in fname in
     cin_ref := Some cin;
@@ -50,11 +50,11 @@ let copy_file fname_from fname_to =
   let cleanup () =
     begin match !cin_ref with
       | None -> ()
-      | Some cin -> close_in cin
+      | Some cin -> In_channel.close cin
     end;
     begin match !cout_ref with
       | None -> ()
-      | Some cout -> close_out cout
+      | Some cout -> Out_channel.close cout
     end in
   try
     let cin = open_in fname_from in
@@ -101,7 +101,7 @@ let do_outf outf_opt f =
 
 (** close an outfile *)
 let close_outf outf =
-  close_out outf.out_c
+  Out_channel.close outf.out_c
 
 (** convert a filename to absolute path and normalize by removing occurrences of "." and ".." *)
 module FileNormalize = struct
@@ -277,7 +277,7 @@ let do_finally f g =
 let with_file file ~f =
   let oc = open_out file in
   let f () = f oc in
-  let g () = close_out oc in
+  let g () = Out_channel.close oc in
   do_finally f g |> fst
 
 let write_json_to_file destfile json =
@@ -299,7 +299,7 @@ let with_process_in command read =
 (** Create a directory if it does not exist already. *)
 let create_dir dir =
   try
-    if (Unix.stat dir).Unix.st_kind != Unix.S_DIR then
+    if (Unix.stat dir).Unix.st_kind <> Unix.S_DIR then
       failwithf "@.ERROR: file %s exists and is not a directory@." dir
   with Unix.Unix_error _ ->
   try Unix.mkdir dir ~perm:0o700 with
diff --git a/infer/src/base/ZipLib.ml b/infer/src/base/ZipLib.ml
index 87503e04f..81ccd8261 100644
--- a/infer/src/base/ZipLib.ml
+++ b/infer/src/base/ZipLib.ml
@@ -28,7 +28,7 @@ let load_from_cache serializer zip_path cache_dir zip_library =
   let absolute_path = Filename.concat cache_dir zip_path in
   let deserialize = Serialization.from_file serializer in
   let extract to_path =
-    if (Sys.file_exists to_path) != `Yes then
+    if (Sys.file_exists to_path) <> `Yes then
       begin
         Unix.mkdir_p (Filename.dirname to_path);
         let lazy zip_channel = zip_library.zip_channel in
diff --git a/infer/src/checkers/IdAccessPathMapDomain.ml b/infer/src/checkers/IdAccessPathMapDomain.ml
index 6009360cf..d5c8a7a71 100644
--- a/infer/src/checkers/IdAccessPathMapDomain.ml
+++ b/infer/src/checkers/IdAccessPathMapDomain.ml
@@ -23,7 +23,7 @@ let pp fmt astate =
 let initial = IdMap.empty
 
 let (<=) ~lhs ~rhs =
-  if lhs == rhs
+  if phys_equal lhs rhs
   then true
   else
     try
@@ -37,7 +37,7 @@ let (<=) ~lhs ~rhs =
     with Not_found -> false
 
 let join astate1 astate2 =
-  if astate1 == astate2
+  if phys_equal astate1 astate2
   then astate1
   else
     IdMap.merge
diff --git a/infer/src/checkers/Trace.ml b/infer/src/checkers/Trace.ml
index f274a8d23..a32765c51 100644
--- a/infer/src/checkers/Trace.ml
+++ b/infer/src/checkers/Trace.ml
@@ -336,7 +336,7 @@ module Make (Spec : Spec) = struct
           |> Sinks.union caller_trace.sinks in
 
       let passthroughs =
-        if sources == caller_trace.sources && sinks == caller_trace.sinks
+        if phys_equal sources caller_trace.sources && phys_equal sinks caller_trace.sinks
         then
           (* this callee didn't add any new sources or any news sinks; it's just a passthrough *)
           Passthroughs.add (Passthrough.make callee_site) caller_trace.passthroughs
@@ -352,13 +352,13 @@ module Make (Spec : Spec) = struct
     { sources; sinks; passthroughs; }
 
   let (<=) ~lhs ~rhs =
-    lhs == rhs ||
+    phys_equal lhs rhs ||
     (Sources.subset lhs.sources rhs.sources &&
      Sinks.subset lhs.sinks rhs.sinks &&
      Passthroughs.subset lhs.passthroughs rhs.passthroughs)
 
   let join t1 t2 =
-    if t1 == t2
+    if phys_equal t1 t2
     then t1
     else
       let sources = Sources.union t1.sources t2.sources in
diff --git a/infer/src/checkers/abstractDomain.ml b/infer/src/checkers/abstractDomain.ml
index 47431e958..bbc1bb043 100644
--- a/infer/src/checkers/abstractDomain.ml
+++ b/infer/src/checkers/abstractDomain.ml
@@ -29,7 +29,7 @@ module BottomLifted (Domain : S) = struct
   let initial = Bottom
 
   let (<=) ~lhs ~rhs =
-    if lhs == rhs
+    if phys_equal lhs rhs
     then true
     else
       match lhs, rhs with
@@ -38,7 +38,7 @@ module BottomLifted (Domain : S) = struct
       | NonBottom lhs, NonBottom rhs -> Domain.(<=) ~lhs ~rhs
 
   let join astate1 astate2 =
-    if astate1 == astate2
+    if phys_equal astate1 astate2
     then astate1
     else
       match astate1, astate2 with
@@ -47,7 +47,7 @@ module BottomLifted (Domain : S) = struct
       | NonBottom a1, NonBottom a2 -> NonBottom (Domain.join a1 a2)
 
   let widen ~prev ~next ~num_iters =
-    if prev == next
+    if phys_equal prev next
     then prev
     else
       match prev, next with
@@ -66,18 +66,18 @@ module Pair (Domain1 : S) (Domain2 : S) = struct
   let initial = Domain1.initial, Domain2.initial
 
   let (<=) ~lhs ~rhs =
-    if lhs == rhs
+    if phys_equal lhs rhs
     then true
     else
       Domain1.(<=) ~lhs:(fst lhs) ~rhs:(fst rhs) && Domain2.(<=) ~lhs:(snd lhs) ~rhs:(snd rhs)
 
   let join astate1 astate2 =
-    if astate1 == astate2
+    if phys_equal astate1 astate2
     then astate1
     else Domain1.join (fst astate1) (fst astate2), Domain2.join (snd astate1) (snd astate2)
 
   let widen ~prev ~next ~num_iters =
-    if prev == next
+    if phys_equal prev next
     then prev
     else
       Domain1.widen ~prev:(fst prev) ~next:(fst next) ~num_iters,
@@ -94,12 +94,12 @@ module FiniteSet (S : PrettyPrintable.PPSet) = struct
   let initial = empty
 
   let (<=) ~lhs ~rhs =
-    if lhs == rhs
+    if phys_equal lhs rhs
     then true
     else subset lhs rhs
 
   let join astate1 astate2 =
-    if astate1 == astate2
+    if phys_equal astate1 astate2
     then astate1
     else union astate1 astate2
 
@@ -115,7 +115,7 @@ module Map (M : PrettyPrintable.PPMap) (ValueDomain : S) = struct
 
   (** true if all keys in [lhs] are in [rhs], and each lhs value <= corresponding rhs value *)
   let (<=) ~lhs ~rhs =
-    if lhs == rhs
+    if phys_equal lhs rhs
     then true
     else
       M.for_all
@@ -125,7 +125,7 @@ module Map (M : PrettyPrintable.PPMap) (ValueDomain : S) = struct
         lhs
 
   let join astate1 astate2 =
-    if astate1 == astate2
+    if phys_equal astate1 astate2
     then astate1
     else
       M.merge
diff --git a/infer/src/checkers/accessPath.ml b/infer/src/checkers/accessPath.ml
index df9f262b7..4cb2cac31 100644
--- a/infer/src/checkers/accessPath.ml
+++ b/infer/src/checkers/accessPath.ml
@@ -105,7 +105,7 @@ let with_base_var var = function
   | Abstracted ((_, base_typ), accesses) -> Abstracted ((var, base_typ), accesses)
 
 let rec is_prefix_path path1 path2 =
-  if path1 == path2
+  if phys_equal path1 path2
   then true
   else
     match path1, path2 with
@@ -114,7 +114,7 @@ let rec is_prefix_path path1 path2 =
     | access1 :: p1, access2 :: p2 -> equal_access access1 access2 && is_prefix_path p1 p2
 
 let is_prefix ((base1, path1) as ap1) ((base2, path2) as ap2) =
-  if ap1 == ap2
+  if phys_equal ap1 ap2
   then true
   else
     equal_base base1 base2 && is_prefix_path path1 path2
diff --git a/infer/src/checkers/accessPathDomains.ml b/infer/src/checkers/accessPathDomains.ml
index c91d70ce2..acd7854bb 100644
--- a/infer/src/checkers/accessPathDomains.ml
+++ b/infer/src/checkers/accessPathDomains.ml
@@ -28,7 +28,8 @@ module Set = struct
 
   let normalize aps =
     APSet.filter
-      (fun lhs -> not (APSet.exists (fun rhs -> lhs != rhs && AccessPath.(<=) ~lhs ~rhs) aps))
+      (fun lhs ->
+         not (APSet.exists (fun rhs -> not (phys_equal lhs rhs) && AccessPath.(<=) ~lhs ~rhs) aps))
       aps
 
   let add = APSet.add
@@ -44,7 +45,7 @@ module Set = struct
     APSet.mem ap aps || APSet.exists (has_overlap ap) aps
 
   let (<=) ~lhs ~rhs =
-    if lhs == rhs
+    if phys_equal lhs rhs
     then true
     else
       let rhs_contains lhs_ap =
@@ -52,12 +53,12 @@ module Set = struct
       APSet.subset lhs rhs || APSet.for_all rhs_contains lhs
 
   let join aps1 aps2 =
-    if aps1 == aps2
+    if phys_equal aps1 aps2
     then aps1
     else APSet.union aps1 aps2
 
   let widen ~prev ~next ~num_iters:_ =
-    if prev == next
+    if phys_equal prev next
     then prev
     else
       let abstract_access_path ap aps = match ap with
diff --git a/infer/src/checkers/accessTree.ml b/infer/src/checkers/accessTree.ml
index a24f18f19..352cb4af6 100644
--- a/infer/src/checkers/accessTree.ml
+++ b/infer/src/checkers/accessTree.ml
@@ -123,7 +123,7 @@ module Make (TraceDomain : AbstractDomain.S) = struct
     Option.map ~f:fst (get_node ap tree)
 
   let rec access_tree_lteq ((lhs_trace, lhs_tree) as lhs) ((rhs_trace, rhs_tree) as rhs) =
-    if lhs == rhs
+    if phys_equal lhs rhs
     then true
     else
       TraceDomain.(<=) ~lhs:lhs_trace ~rhs:rhs_trace &&
@@ -142,7 +142,7 @@ module Make (TraceDomain : AbstractDomain.S) = struct
           false
 
   let (<=) ~lhs ~rhs =
-    if lhs == rhs
+    if phys_equal lhs rhs
     then true
     else
       BaseMap.for_all
@@ -154,7 +154,7 @@ module Make (TraceDomain : AbstractDomain.S) = struct
         lhs
 
   let node_join f_node_merge f_trace_merge ((trace1, tree1) as node1) ((trace2, tree2) as node2) =
-    if node1 == node2
+    if phys_equal node1 node2
     then node1
     else
       let trace' = f_trace_merge trace1 trace2 in
@@ -163,21 +163,21 @@ module Make (TraceDomain : AbstractDomain.S) = struct
       match tree1, tree2 with
       | Subtree subtree1, Subtree subtree2 ->
           let tree' = AccessMap.merge (fun _ v1 v2 -> f_node_merge v1 v2) subtree1 subtree2 in
-          if trace' == trace1 && tree' == subtree1
+          if phys_equal trace' trace1 && phys_equal tree' subtree1
           then node1
-          else if trace' == trace2 && tree' == subtree2
+          else if phys_equal trace' trace2 && phys_equal tree' subtree2
           then node2
           else trace', Subtree tree'
       | Star, t ->
           (* vacuum up all the traces associated with the subtree t and join them with trace' *)
           let trace'' = join_all_traces trace' t in
-          if trace'' == trace1
+          if phys_equal trace'' trace1
           then node1
           else trace'', Star
       | t, Star ->
           (* same as above, but kind-of duplicated to allow address equality optimization *)
           let trace'' = join_all_traces trace' t in
-          if trace'' == trace2
+          if phys_equal trace'' trace2
           then node2
           else trace'', Star
 
@@ -185,9 +185,9 @@ module Make (TraceDomain : AbstractDomain.S) = struct
     match node1_opt, node2_opt with
     | Some node1, Some node2 ->
         let joined_node = node_join node_merge TraceDomain.join node1 node2 in
-        if joined_node == node1
+        if phys_equal joined_node node1
         then node1_opt
-        else if joined_node == node2
+        else if phys_equal joined_node node2
         then node2_opt
         else Some joined_node
     | None, node_opt | node_opt, None ->
@@ -243,7 +243,7 @@ module Make (TraceDomain : AbstractDomain.S) = struct
     add_node ap (make_normal_leaf trace) tree
 
   let join tree1 tree2 =
-    if tree1 == tree2
+    if phys_equal tree1 tree2
     then tree1
     else BaseMap.merge (fun _ n1 n2 -> node_merge n1 n2) tree1 tree2
 
@@ -271,13 +271,13 @@ module Make (TraceDomain : AbstractDomain.S) = struct
         then make_starred_leaf trace
         else
           let subtree' = AccessMap.map node_add_stars subtree in
-          if subtree' == subtree
+          if phys_equal subtree' subtree
           then node
           else trace, Subtree subtree'
     | Star -> node
 
   let widen ~prev ~next ~num_iters =
-    if prev == next
+    if phys_equal prev next
     then prev
     else
       let trace_widen prev next =
@@ -286,14 +286,14 @@ module Make (TraceDomain : AbstractDomain.S) = struct
         match prev_node_opt, next_node_opt with
         | Some prev_node, Some next_node ->
             let widened_node = node_join node_widen trace_widen prev_node next_node in
-            if widened_node == prev_node
+            if phys_equal widened_node prev_node
             then prev_node_opt
-            else if widened_node == next_node
+            else if phys_equal widened_node next_node
             then next_node_opt
             else Some widened_node
         | None, Some next_node ->
             let widened_node = node_add_stars next_node in
-            if widened_node == next_node
+            if phys_equal widened_node next_node
             then next_node_opt
             else Some widened_node
         | Some _, None | None, None ->
diff --git a/infer/src/checkers/annotationReachability.ml b/infer/src/checkers/annotationReachability.ml
index 5ff4c8ce8..067fe1cb4 100644
--- a/infer/src/checkers/annotationReachability.ml
+++ b/infer/src/checkers/annotationReachability.ml
@@ -53,7 +53,7 @@ module Domain = struct
           try CallsDomain.find key call_map
           with Not_found -> CallSiteSet.empty in
         let call_set' = CallSiteSet.add call call_set in
-        if call_set' == call_set
+        if phys_equal call_set' call_set
         then astate
         else NonBottom (CallsDomain.add key call_set' call_map, vars)
 
diff --git a/infer/src/checkers/copyPropagation.ml b/infer/src/checkers/copyPropagation.ml
index de6ae4588..fd8422341 100644
--- a/infer/src/checkers/copyPropagation.ml
+++ b/infer/src/checkers/copyPropagation.ml
@@ -21,7 +21,7 @@ module Domain = struct
   (* return true if the key-value bindings in [rhs] are a subset of the key-value bindings in
      [lhs] *)
   let (<=) ~lhs ~rhs =
-    if lhs == rhs
+    if phys_equal lhs rhs
     then true
     else
       Var.Map.for_all
@@ -31,7 +31,7 @@ module Domain = struct
         rhs
 
   let join astate1 astate2 =
-    if astate1 == astate2
+    if phys_equal astate1 astate2
     then astate1
     else
       let keep_if_same _ v1_opt v2_opt = match v1_opt, v2_opt with
diff --git a/infer/src/clang/Capture.re b/infer/src/clang/Capture.re
index 02f462122..110386fbb 100644
--- a/infer/src/clang/Capture.re
+++ b/infer/src/clang/Capture.re
@@ -155,7 +155,7 @@ let run_plugin_and_frontend source_path frontend clang_args => {
       Config.etc_dir
       biniou_fname
       basename;
-    close_out debug_script_out
+    Out_channel.close debug_script_out
   };
   run_clang clang_command frontend
 };
diff --git a/infer/src/clang/cContext.ml b/infer/src/clang/cContext.ml
index 1529b5233..dad5bdb7d 100644
--- a/infer/src/clang/cContext.ml
+++ b/infer/src/clang/cContext.ml
@@ -33,7 +33,7 @@ type curr_class =
 [@@deriving compare]
 
 let equal_curr_class curr_class1 curr_class2 =
-  compare_curr_class curr_class1 curr_class2 == 0
+  compare_curr_class curr_class1 curr_class2 = 0
 
 type str_node_map = (string, Procdesc.Node.t) Hashtbl.t
 
diff --git a/infer/src/clang/cFrontend_checkers_main.ml b/infer/src/clang/cFrontend_checkers_main.ml
index 3a9ac96a1..346531078 100644
--- a/infer/src/clang/cFrontend_checkers_main.ml
+++ b/infer/src/clang/cFrontend_checkers_main.ml
@@ -31,7 +31,7 @@ let parse_ctl_file filename =
       let lexbuf = Lexing.from_channel inx in
       lexbuf.lex_curr_p <- { lexbuf.lex_curr_p with pos_fname = fn };
       let _ = parse_with_error lexbuf in
-      close_in inx
+      In_channel.close inx
   | None ->
       Logging.out "No linters file specified. Nothing to parse.\n"
 
diff --git a/infer/src/clang/cFrontend_utils.ml b/infer/src/clang/cFrontend_utils.ml
index 980871298..25d1ca6f2 100644
--- a/infer/src/clang/cFrontend_utils.ml
+++ b/infer/src/clang/cFrontend_utils.ml
@@ -671,7 +671,7 @@ struct
       | Some m when is_cpp_translation translation_unit_context -> m
       | _ -> "" in
     let mangled = (Utils.string_crc_hex32 file) ^ mangled_name in
-    if String.length file == 0 && String.length mangled_name == 0 then
+    if String.length file = 0 && String.length mangled_name = 0 then
       Procname.from_string_c_fun name
     else
       Procname.C (Procname.c name mangled)
diff --git a/infer/src/clang/cMethod_signature.ml b/infer/src/clang/cMethod_signature.ml
index cd9fbafe7..f8d7aa0bc 100644
--- a/infer/src/clang/cMethod_signature.ml
+++ b/infer/src/clang/cMethod_signature.ml
@@ -67,13 +67,13 @@ let ms_get_return_param_typ { return_param_typ } =
 (* it has 1 argument (this includes self) *)
 let ms_is_getter { pointer_to_property_opt; args }  =
   Option.is_some pointer_to_property_opt &&
-  IList.length args == 1
+  IList.length args = 1
 
 (* A method is a setter if it has a link to a property and *)
 (* it has 2 argument (this includes self) *)
 let ms_is_setter { pointer_to_property_opt; args } =
   Option.is_some pointer_to_property_opt &&
-  IList.length args == 2
+  IList.length args = 2
 
 let make_ms name args ret_type attributes loc is_instance ?is_cpp_virtual language pointer_to_parent
     pointer_to_property_opt return_param_typ =
diff --git a/infer/src/clang/cMethod_trans.ml b/infer/src/clang/cMethod_trans.ml
index 7c3f7d632..c0dcf8a9f 100644
--- a/infer/src/clang/cMethod_trans.ml
+++ b/infer/src/clang/cMethod_trans.ml
@@ -379,7 +379,7 @@ let get_const_args_indices ~shift args =
 
 (** Creates a procedure description. *)
 let create_local_procdesc trans_unit_ctx cfg tenv ms fbody captured is_objc_inst_method =
-  let defined = not ((IList.length fbody) == 0) in
+  let defined = not ((IList.length fbody) = 0) in
   let proc_name = CMethod_signature.ms_get_name ms in
   let pname = Procname.to_string proc_name in
   let attributes = sil_func_attributes_of_attributes (CMethod_signature.ms_get_attributes ms) in
diff --git a/infer/src/clang/cTrans.ml b/infer/src/clang/cTrans.ml
index fc714ae2b..b00996b08 100644
--- a/infer/src/clang/cTrans.ml
+++ b/infer/src/clang/cTrans.ml
@@ -28,7 +28,7 @@ struct
     let open CContext in
     let (selector, method_pointer_opt, mc_type) =
       CMethod_trans.get_objc_method_data obj_c_message_expr_info in
-    let is_instance = mc_type != CMethod_trans.MCStatic in
+    let is_instance = mc_type <> CMethod_trans.MCStatic in
     let method_kind = Procname.objc_method_kind_of_bool is_instance in
     let ms_opt =
       match method_pointer_opt with
@@ -1631,7 +1631,7 @@ struct
     let res_trans_subexpr_list =
       initListExpr_initializers_trans trans_state var_exp 0 stmts typ false stmt_info in
     let rh_exps = collect_exprs res_trans_subexpr_list in
-    if IList.length rh_exps == 0 then
+    if IList.length rh_exps = 0 then
       let exps =
         match Sil.zero_value_of_numerical_type_option var_type with
         | Some zero_exp -> [(zero_exp, typ)]
@@ -1645,7 +1645,7 @@ struct
           let i = IList.length lh - IList.length rh_exps in
           IList.drop_last i lh
         else lh in
-      if IList.length rh_exps == IList.length lh then
+      if IList.length rh_exps = IList.length lh then
         (* Creating new instructions by assigning right hand side to left hand side expressions *)
         let assign_instr (lh_exp, lh_t) (rh_exp, _) = Sil.Store (lh_exp, lh_t, rh_exp, sil_loc) in
         let assign_instrs =
diff --git a/infer/src/eradicate/typeState.ml b/infer/src/eradicate/typeState.ml
index da0f65da6..2b50a1972 100644
--- a/infer/src/eradicate/typeState.ml
+++ b/infer/src/eradicate/typeState.ml
@@ -114,7 +114,7 @@ let map_join m1 m2 =
         let ta1' = TypeAnnotation.with_origin ta1 TypeOrigin.Undef in
         (t1, ta1', locs1) in
       tjoined := M.add exp1 range1' !tjoined in
-  if m1 == m2 then m1
+  if phys_equal m1 m2 then m1
   else (
     M.iter extend_lhs m2;
     M.iter missing_rhs m1;
@@ -141,17 +141,17 @@ let lookup_pvar pvar typestate =
 
 let add_id id range typestate =
   let map' = M.add (Exp.Var id) range typestate.map in
-  if map' == typestate.map then typestate
+  if phys_equal map' typestate.map then typestate
   else { typestate with map = map' }
 
 let add pvar range typestate =
   let map' = M.add (Exp.Lvar pvar) range typestate.map in
-  if map' == typestate.map then typestate
+  if phys_equal map' typestate.map then typestate
   else { typestate with map = map' }
 
 let remove_id id typestate =
   let map' = M.remove (Exp.Var id) typestate.map in
-  if map' == typestate.map then typestate
+  if phys_equal map' typestate.map then typestate
   else { typestate with map = map' }
 
 let get_extension typestate = typestate.extension
diff --git a/infer/src/java/jClasspath.ml b/infer/src/java/jClasspath.ml
index df7ba6d14..56964136f 100644
--- a/infer/src/java/jClasspath.ml
+++ b/infer/src/java/jClasspath.ml
@@ -103,7 +103,7 @@ let read_package_declaration source_file =
       | hd::package::[] when hd = "package" -> package
       | _ -> loop ()
     with End_of_file ->
-      close_in file_in;
+      In_channel.close file_in;
       empty_package in
   loop ()
 
@@ -177,7 +177,7 @@ let load_from_verbose_output () =
     | JBasics.Class_structure_error _
     | Invalid_argument _ -> loop paths roots sources classes
     | End_of_file ->
-        close_in file_in;
+        In_channel.close file_in;
         let classpath =
           IList.fold_left
             append_path
diff --git a/infer/src/java/jFrontend.ml b/infer/src/java/jFrontend.ml
index bed487033..b43cd6671 100644
--- a/infer/src/java/jFrontend.ml
+++ b/infer/src/java/jFrontend.ml
@@ -111,7 +111,7 @@ let cache_classname cn =
     split [] (Filename.dirname path) in
   let rec mkdir l p =
     let () =
-      if (Sys.file_exists p) != `Yes then
+      if (Sys.file_exists p) <> `Yes then
         Unix.mkdir p ~perm:493 in
     match l with
     | [] -> ()
@@ -119,7 +119,7 @@ let cache_classname cn =
   mkdir splitted_root_dir Filename.dir_sep;
   let file_out = open_out(path) in
   output_string file_out (string_of_float (Unix.time ()));
-  close_out file_out
+  Out_channel.close file_out
 
 let is_classname_cached cn =
   Sys.file_exists (path_of_cached_classname cn) = `Yes
diff --git a/infer/src/java/jMain.ml b/infer/src/java/jMain.ml
index e7f26a841..94f1f88c9 100644
--- a/infer/src/java/jMain.ml
+++ b/infer/src/java/jMain.ml
@@ -15,7 +15,7 @@ open Javalib_pack
 module L = Logging
 
 let () =
-  match Config.models_mode, Sys.file_exists Config.models_jar == `Yes with
+  match Config.models_mode, Sys.file_exists Config.models_jar = `Yes with
   | true, false ->
       ()
   | false, false ->
diff --git a/infer/src/quandary/TaintAnalysis.ml b/infer/src/quandary/TaintAnalysis.ml
index abbe99024..5a71df659 100644
--- a/infer/src/quandary/TaintAnalysis.ml
+++ b/infer/src/quandary/TaintAnalysis.ml
@@ -48,14 +48,14 @@ module Make (TaintSpecification : TaintSpec.S) = struct
       { access_tree; id_map; }
 
     let (<=) ~lhs ~rhs =
-      if lhs == rhs
+      if phys_equal lhs rhs
       then true
       else
         TaintDomain.(<=) ~lhs:lhs.access_tree ~rhs:rhs.access_tree &&
         IdMapDomain.(<=) ~lhs:lhs.id_map ~rhs:rhs.id_map
 
     let join astate1 astate2 =
-      if astate1 == astate2
+      if phys_equal astate1 astate2
       then astate1
       else
         let access_tree = TaintDomain.join astate1.access_tree astate2.access_tree in
@@ -63,7 +63,7 @@ module Make (TaintSpecification : TaintSpec.S) = struct
         { access_tree; id_map; }
 
     let widen ~prev ~next ~num_iters =
-      if prev == next
+      if phys_equal prev next
       then prev
       else
         let access_tree =
@@ -281,7 +281,7 @@ module Make (TaintSpecification : TaintSpec.S) = struct
             let output_trace = TaintSpecification.of_summary_trace in_out_summary.output_trace in
             let appended_trace = TraceDomain.append in_trace output_trace callee_site in
             let joined_trace = TraceDomain.join caller_trace appended_trace in
-            if appended_trace == joined_trace
+            if phys_equal appended_trace joined_trace
             then
               access_tree
             else
diff --git a/infer/src/unit/accessTreeTests.ml b/infer/src/unit/accessTreeTests.ml
index 3c993badc..8ebcfd672 100644
--- a/infer/src/unit/accessTreeTests.ml
+++ b/infer/src/unit/accessTreeTests.ml
@@ -26,7 +26,7 @@ module MockTraceDomain = struct
   (* stop others from creating top by accident, adding to top, or removing it *)
   let add e s =
     assert (e <> top_str);
-    if s == top
+    if phys_equal s top
     then top
     else add e s
 
@@ -43,7 +43,7 @@ module MockTraceDomain = struct
 
   (* similarly, hack printing so top looks different *)
   let pp fmt s =
-    if s == top
+    if phys_equal s top
     then F.fprintf fmt "T"
     else pp fmt s
 end
diff --git a/infer/src/unit/procCfgTests.ml b/infer/src/unit/procCfgTests.ml
index 9981c4d5f..8318d030f 100644
--- a/infer/src/unit/procCfgTests.ml
+++ b/infer/src/unit/procCfgTests.ml
@@ -61,15 +61,15 @@ let tests =
       begin
         match ProcCfg.Normal.instrs n1 with
         | [instr1; instr2] ->
-            assert_bool "First instr should be dummy_instr1" (instr1 == dummy_instr1);
-            assert_bool "Second instr should be dummy_instr2" (instr2 == dummy_instr2);
+            assert_bool "First instr should be dummy_instr1" (phys_equal instr1 dummy_instr1);
+            assert_bool "Second instr should be dummy_instr2" (phys_equal instr2 dummy_instr2);
         | _ -> assert_failure "Expected exactly two instructions"
       end;
       begin
         match BackwardCfg.instrs n1 with
         | [instr1; instr2] ->
-            assert_bool "First instr should be dummy_instr2" (instr1 == dummy_instr2);
-            assert_bool "Second instr should be dummy_instr1" (instr2 == dummy_instr1);
+            assert_bool "First instr should be dummy_instr2" (phys_equal instr1 dummy_instr2);
+            assert_bool "Second instr should be dummy_instr1" (phys_equal instr2 dummy_instr1);
         | _ -> assert_failure "Expected exactly two instructions"
       end;
       begin
@@ -77,10 +77,10 @@ let tests =
         match InstrCfg.instr_ids n1 with
         | [ (instr1, Some (id1, ProcCfg.Instr_index 0));
             (instr2, Some (id2, ProcCfg.Instr_index 1)); ] ->
-            assert_bool "First instr should be dummy_instr1" (instr1 == dummy_instr1);
-            assert_bool "Second instr should be dummy_instr2" (instr2 == dummy_instr2);
-            assert_bool "id1 should be id of underlying node" (id1 == node_id);
-            assert_bool "id2 should be id of underlying node" (id2 == node_id);
+            assert_bool "First instr should be dummy_instr1" (phys_equal instr1 dummy_instr1);
+            assert_bool "Second instr should be dummy_instr2" (phys_equal instr2 dummy_instr2);
+            assert_bool "id1 should be id of underlying node" (phys_equal id1 node_id);
+            assert_bool "id2 should be id of underlying node" (phys_equal id2 node_id);
         | _ -> assert_failure "Expected exactly two instructions with correct indices"
       end;
       let backward_node_id, _ = BackwardInstrCfg.id n1 in
@@ -88,10 +88,10 @@ let tests =
         match BackwardInstrCfg.instr_ids n1 with
         | [ (instr1, Some (id1, ProcCfg.Instr_index 1));
             (instr2, Some (id2, ProcCfg.Instr_index 0)); ] ->
-            assert_bool "First instr should be dummy_instr2" (instr1 == dummy_instr2);
-            assert_bool "Second instr should be dummy_instr1" (instr2 == dummy_instr1);
-            assert_bool "id1 should be id of underlying node" (id1 == backward_node_id);
-            assert_bool "id2 should be id of underlying node" (id2 == backward_node_id);
+            assert_bool "First instr should be dummy_instr2" (phys_equal instr1 dummy_instr2);
+            assert_bool "Second instr should be dummy_instr1" (phys_equal instr2 dummy_instr1);
+            assert_bool "id1 should be id of underlying node" (phys_equal id1 backward_node_id);
+            assert_bool "id2 should be id of underlying node" (phys_equal id2 backward_node_id);
         | _ -> assert_failure "Expected exactly two instructions with correct indices"
       end;
       assert_bool