Merge branch 'egil/tools/fix-unmatched_return/OTP-13595'

* egil/tools/fix-unmatched_return/OTP-13595:
  xref: Fix unmatched return warnings
  tags: Fix unmatched return warnings
  lcnt: Fix unmatched return warnings
  fprof: Fix unmatched return warnings
  fprof: Fix unmatched return warnings
  eprof: Fix unmatched return warnings
  cover: Fix unmatched return warnings

6 files changed, 158 insertions, 152 deletions

diff --git a/lib/tools/src/cover.erl b/lib/tools/src/cover.erl
index 69331732bf..92c10cc306 100644
--- a/lib/tools/src/cover.erl
+++ b/lib/tools/src/cover.erl
@@ -573,7 +573,7 @@ call(Request) ->
     Ref = erlang:monitor(process,?SERVER),
     receive {'DOWN', Ref, _Type, _Object, noproc} -> 
 	    erlang:demonitor(Ref),
-	    start(),
+            {ok,_} = start(),
 	    call(Request)
     after 0 ->
 	    ?SERVER ! {self(),Request},
@@ -589,7 +589,9 @@ call(Request) ->
     end.
 
 reply(From, Reply) ->
-    From ! {?SERVER,Reply}.
+    From ! {?SERVER,Reply},
+    ok.
+
 is_from(From) ->
     is_pid(From).
 
@@ -615,9 +617,11 @@ remote_call(Node,Request) ->
     end.
     
 remote_reply(Proc,Reply) when is_pid(Proc) ->
-    Proc ! {?SERVER,Reply};
+    Proc ! {?SERVER,Reply},
+    ok;
 remote_reply(MainNode,Reply) ->
-    {?SERVER,MainNode} ! {?SERVER,Reply}.
+    {?SERVER,MainNode} ! {?SERVER,Reply},
+    ok.
 
 %%%----------------------------------------------------------------------
 %%% cover_server on main node
@@ -627,14 +631,16 @@ init_main(Starter) ->
     register(?SERVER,self()),
     %% Having write concurrancy here gives a 40% performance boost
     %% when collect/1 is called. 
-    ets:new(?COVER_TABLE, [set, public, named_table
-			   ,{write_concurrency, true}
-			  ]),
-    ets:new(?COVER_CLAUSE_TABLE, [set, public, named_table]),
-    ets:new(?BINARY_TABLE, [set, public, named_table]),
-    ets:new(?COLLECTION_TABLE, [set, public, named_table]),
-    ets:new(?COLLECTION_CLAUSE_TABLE, [set, public, named_table]),
-    net_kernel:monitor_nodes(true),
+    ?COVER_TABLE = ets:new(?COVER_TABLE, [set, public, named_table,
+                                          {write_concurrency, true}]),
+    ?COVER_CLAUSE_TABLE = ets:new(?COVER_CLAUSE_TABLE, [set, public,
+                                                        named_table]),
+    ?BINARY_TABLE = ets:new(?BINARY_TABLE, [set, public, named_table]),
+    ?COLLECTION_TABLE = ets:new(?COLLECTION_TABLE, [set, public,
+                                                    named_table]),
+    ?COLLECTION_CLAUSE_TABLE = ets:new(?COLLECTION_CLAUSE_TABLE, [set, public,
+                                                                  named_table]),
+    ok = net_kernel:monitor_nodes(true),
     Starter ! {?SERVER,started},
     main_process_loop(#main_state{}).
 
@@ -672,7 +678,7 @@ main_process_loop(State) ->
 		    Imported = do_import_to_table(Fd,File,
 						  State#main_state.imported),
 		    reply(From, ok),
-		    file:close(Fd),
+		    ok = file:close(Fd),
 		    main_process_loop(State#main_state{imported=Imported});
 		{error,Reason} ->
 		    reply(From, {error, {cant_open_file,File,Reason}}),
@@ -870,11 +876,12 @@ main_process_loop(State) ->
 
 init_remote(Starter,MainNode) ->
     register(?SERVER,self()),
-    ets:new(?COVER_TABLE, [set, public, named_table
-			   %% write_concurrency here makes otp_8270 break :(
-			   %,{write_concurrency, true}
-			  ]),
-    ets:new(?COVER_CLAUSE_TABLE, [set, public, named_table]),
+    %% write_concurrency here makes otp_8270 break :(
+    ?COVER_TABLE = ets:new(?COVER_TABLE, [set, public, named_table
+                                          %,{write_concurrency, true}
+                                         ]),
+    ?COVER_CLAUSE_TABLE = ets:new(?COVER_CLAUSE_TABLE, [set, public,
+                                                        named_table]),
     Starter ! {self(),started},
     remote_process_loop(#remote_state{main_node=MainNode}).
 
@@ -907,11 +914,11 @@ remote_process_loop(State) ->
 			  '_' -> [M || {M,_} <- State#remote_state.compiled];
 			  _ -> Modules0
 		      end,
-	   spawn(fun() ->
-			 ?SPAWN_DBG(remote_collect, 
-				    {Modules, CollectorPid, From}),
-			 do_collect(Modules, CollectorPid, From)
-		 end),
+            spawn(fun() ->
+                          ?SPAWN_DBG(remote_collect, 
+                                     {Modules, CollectorPid, From}),
+                          do_collect(Modules, CollectorPid, From)
+                  end),
 	    remote_process_loop(State);
 
 	{remote,stop} ->
@@ -952,13 +959,13 @@ remote_process_loop(State) ->
     end.
 
 do_collect(Modules, CollectorPid, From) ->
-    pmap(
-      fun(Module) ->
-	      Pattern = {#bump{module=Module, _='_'}, '$1'},
-	      MatchSpec = [{Pattern,[{'=/=','$1',0}],['$_']}],
-	      Match = ets:select(?COVER_TABLE,MatchSpec,?CHUNK_SIZE),
-	      send_chunks(Match, CollectorPid, [])
-      end,Modules),
+    _ = pmap(
+          fun(Module) ->
+                  Pattern = {#bump{module=Module, _='_'}, '$1'},
+                  MatchSpec = [{Pattern,[{'=/=','$1',0}],['$_']}],
+                  Match = ets:select(?COVER_TABLE,MatchSpec,?CHUNK_SIZE),
+                  send_chunks(Match, CollectorPid, [])
+          end,Modules),
     CollectorPid ! done,
     remote_reply(From, ok).
 
@@ -994,20 +1001,20 @@ get_downs(Mons) ->
     end.
 
 reload_originals(Compiled) ->
-    Modules = [M || {M,_} <- Compiled],
-    pmap(fun do_reload_original/1, Modules).
+    _ = pmap(fun do_reload_original/1, [M || {M,_} <- Compiled]),
+    ok.
 
 do_reload_original(Module) ->
     case code:which(Module) of
 	?TAG ->
-	    code:purge(Module),     % remove code marked as 'old'
-	    code:delete(Module),    % mark cover compiled code as 'old'
+	    _ = code:purge(Module),     % remove code marked as 'old'
+	    _ = code:delete(Module),    % mark cover compiled code as 'old'
 	    %% Note: original beam code must be loaded before the cover
 	    %% compiled code is purged, in order to for references to
 	    %% 'fun M:F/A' and %% 'fun F/A' funs to be correct (they
 	    %% refer to (M:)F/A in the *latest* version  of the module)
-	    code:load_file(Module), % load original code
-	    code:purge(Module);     % remove cover compiled code
+            _ = code:load_file(Module), % load original code
+	    _ = code:purge(Module);     % remove cover compiled code
 	_ ->
 	    ignore
     end.
@@ -1219,12 +1226,13 @@ remote_reset(Module,Nodes) ->
 
 %% Collect data from remote nodes - used for analyse or stop(Node)
 remote_collect(Modules,Nodes,Stop) ->
-    pmap(fun(Node) -> 
-		 ?SPAWN_DBG(remote_collect, 
-			    {Modules, Nodes, Stop}),
-		 do_collection(Node, Modules, Stop)
-	 end,
-	 Nodes).
+    _ = pmap(
+          fun(Node) -> 
+                  ?SPAWN_DBG(remote_collect, 
+                             {Modules, Nodes, Stop}),
+                  do_collection(Node, Modules, Stop)
+          end, Nodes),
+    ok.
 
 do_collection(Node, Module, Stop) ->
     CollectorPid = spawn(fun collector_proc/0),
@@ -1260,8 +1268,8 @@ insert_in_collection_table([]) ->
 insert_in_collection_table(Key,Val) ->
     case ets:member(?COLLECTION_TABLE,Key) of
 	true ->
-	    ets:update_counter(?COLLECTION_TABLE,
-			       Key,Val);
+	    _ = ets:update_counter(?COLLECTION_TABLE, Key,Val),
+            ok;
 	false ->
 	    %% Make sure that there are no race conditions from ets:member
 	    case ets:insert_new(?COLLECTION_TABLE,{Key,Val}) of
@@ -2421,7 +2429,7 @@ do_analyse_to_file1(Module, OutFile, ErlFile, HTML) ->
                                 "<body style='background-color: white;"
                                 " color: black'>\n"
                                 "<pre>\n"],
-                           file:write(OutFd,Header);
+                           ok = file:write(OutFd,Header);
 		       true -> ok
 		    end,
 		    
@@ -2435,7 +2443,7 @@ do_analyse_to_file1(Module, OutFile, ErlFile, HTML) ->
                                       string:right(integer_to_list(H),  2, $0),
                                       string:right(integer_to_list(Mi), 2, $0),
                                       string:right(integer_to_list(S),  2, $0)]),
-                    file:write(OutFd,
+                    ok = file:write(OutFd,
                                ["File generated from ",ErlFile," by COVER ",
                                 Timestamp,"\n\n"
                                 "**************************************"
@@ -2447,14 +2455,13 @@ do_analyse_to_file1(Module, OutFile, ErlFile, HTML) ->
 		    CovLines = lists:keysort(1,ets:select(?COLLECTION_TABLE, MS)),
 		    print_lines(Module, CovLines, InFd, OutFd, 1, HTML),
 		    
-		    if
-			HTML ->
-			    file:write(OutFd, "</pre>\n</body>\n</html>\n");
+		    if HTML ->
+                           ok = file:write(OutFd, "</pre>\n</body>\n</html>\n");
 		       true -> ok
 		    end,
 
-		    file:close(OutFd),
-		    file:close(InFd),
+		    ok = file:close(OutFd),
+		    ok = file:close(InFd),
 
 		    {ok, OutFile};
 
@@ -2472,34 +2479,33 @@ print_lines(Module, CovLines, InFd, OutFd, L, HTML) ->
 	eof ->
 	    ignore;
 	{ok,"%"++_=Line} ->		 %Comment line - not executed.
-	    file:write(OutFd, [tab(),escape_lt_and_gt(Line, HTML)]),
+	    ok = file:write(OutFd, [tab(),escape_lt_and_gt(Line, HTML)]),
 	    print_lines(Module, CovLines, InFd, OutFd, L+1, HTML);
 	{ok,RawLine} ->
 	    Line = escape_lt_and_gt(RawLine,HTML),
 	    case CovLines of
 	       [{L,N}|CovLines1] ->
 		    %% N = lists:foldl(fun([Ni], Nacc) -> Nacc+Ni end, 0, Ns),
-		    if
-			N=:=0, HTML=:=true ->
-			    LineNoNL = Line -- "\n",
-			    Str = "     0",
-			    %%Str = string:right("0", 6, 32),
-			    RedLine = ["<font color=red>",Str,fill1(),
-				       LineNoNL,"</font>\n"],
-			    file:write(OutFd, RedLine);
-			N<1000000 ->
-			    Str = string:right(integer_to_list(N), 6, 32),
-			    file:write(OutFd, [Str,fill1(),Line]);
-			N<10000000 ->
-			    Str = integer_to_list(N),
-			    file:write(OutFd, [Str,fill2(),Line]);
-			true ->
-			    Str = integer_to_list(N),
-			    file:write(OutFd, [Str,fill3(),Line])
-		    end,
+                    if N=:=0, HTML=:=true ->
+                           LineNoNL = Line -- "\n",
+                           Str = "     0",
+                           %%Str = string:right("0", 6, 32),
+                           RedLine = ["<font color=red>",Str,fill1(),
+                                      LineNoNL,"</font>\n"],
+                           ok = file:write(OutFd, RedLine);
+                       N < 1000000 ->
+                           Str = string:right(integer_to_list(N), 6, 32),
+                           ok = file:write(OutFd, [Str,fill1(),Line]);
+                       N < 10000000 ->
+                           Str = integer_to_list(N),
+                           ok = file:write(OutFd, [Str,fill2(),Line]);
+                       true ->
+                           Str = integer_to_list(N),
+                           ok = file:write(OutFd, [Str,fill3(),Line])
+                    end,
 		    print_lines(Module, CovLines1, InFd, OutFd, L+1, HTML);
 		_ ->
-		    file:write(OutFd, [tab(),Line]),
+		    ok = file:write(OutFd, [tab(),Line]),
 		    print_lines(Module, CovLines, InFd, OutFd, L+1, HTML)
 	    end
     end.
@@ -2539,7 +2545,7 @@ do_export(Module, OutFile, From, State) ->
 				{error,{not_cover_compiled,Module}}
 			end
 		end,
-	    file:close(Fd),
+	    ok = file:close(Fd),
 	    reply(From, Reply);
 	{error,Reason} ->
 	    reply(From, {error, {cant_open_file,OutFile,Reason}})
@@ -2581,10 +2587,9 @@ write(Element,Fd) ->
     case byte_size(Bin) of
 	Size when Size > 255 ->
 	    SizeBin = term_to_binary({'$size',Size}),
-	    file:write(Fd,
-                       <<(byte_size(SizeBin)):8,SizeBin/binary,Bin/binary>>);
+	    ok = file:write(Fd, <<(byte_size(SizeBin)):8,SizeBin/binary,Bin/binary>>);
 	Size ->
-	    file:write(Fd,<<Size:8,Bin/binary>>)
+	    ok = file:write(Fd,<<Size:8,Bin/binary>>)
     end,
     ok.    
 
diff --git a/lib/tools/src/eprof.erl b/lib/tools/src/eprof.erl
index 07e995993b..3ae899a078 100644
--- a/lib/tools/src/eprof.erl
+++ b/lib/tools/src/eprof.erl
@@ -74,7 +74,6 @@
 start() -> gen_server:start({local, ?MODULE}, ?MODULE, [], []).
 stop()  -> gen_server:call(?MODULE, stop, infinity).
 
-
 analyze() ->
     analyze(procs).
 
@@ -112,7 +111,7 @@ profile(Rootset, M, F, A, Pattern) when is_list(Rootset), is_atom(M), is_atom(F)
 
 %% Returns when M:F/A has terminated
 profile(Rootset, M, F, A, Pattern, Options) ->
-    start(),
+    ok = start_internal(),
     gen_server:call(?MODULE, {profile_start, Rootset, Pattern, {M,F,A}, Options}, infinity).
 
 dump() -> 
@@ -127,7 +126,7 @@ start_profiling(Rootset) ->
 start_profiling(Rootset, Pattern) ->
     start_profiling(Rootset, Pattern, ?default_options).
 start_profiling(Rootset, Pattern, Options) ->
-    start(),
+    ok = start_internal(),
     gen_server:call(?MODULE, {profile_start, Rootset, Pattern, undefined, Options}, infinity).
 
 stop_profiling() ->
@@ -251,9 +250,9 @@ handle_call({logfile, File}, _From, #state{ fd = OldFd } = S) ->
 	{ok, Fd} ->
 	    case OldFd of
 		undefined -> ok;
-		OldFd -> file:close(OldFd)
+		OldFd -> ok = file:close(OldFd)
 	    end,
-	    {reply, ok, S#state{ fd = Fd}};
+	    {reply, ok, S#state{fd = Fd}};
 	Error ->
 	    {reply, Error, S}
     end;
@@ -521,3 +520,10 @@ format(Fd, Format, Strings) ->
 
 divide(_,0) -> 0.0;
 divide(T,N) -> T/N.
+
+start_internal() ->
+    case start() of
+        {ok, _} -> ok;
+        {error, {already_started,_}} -> ok;
+        Error -> Error
+    end.
diff --git a/lib/tools/src/fprof.erl b/lib/tools/src/fprof.erl
index b21eedc625..8db23dd151 100644
--- a/lib/tools/src/fprof.erl
+++ b/lib/tools/src/fprof.erl
@@ -1003,7 +1003,7 @@ handle_req(#analyse{dest = Dest,
 			already_open ->
 			    ok;
 			ok ->
-			    file:close(DestPid)
+			    ok = file:close(DestPid)
 		    end,
 		    State
 	    end;
@@ -1364,7 +1364,7 @@ tracer_loop(Parent, Handler, State) ->
 	Trace when element(1, Trace) =:= trace_ts ->
 	    tracer_loop(Parent, Handler, Handler(Trace, State));
 	{'EXIT', Parent, Reason} ->
-	    handler(end_of_trace, State),
+	    _ = handler(end_of_trace, State),
 	    exit(Reason);
 	_ ->
 	    tracer_loop(Parent, Handler, State)
@@ -1450,12 +1450,10 @@ end_of_trace(Table, TS) ->
     Procs = get(),
     put(table, Table),
     ?dbg(2, "get() -> ~p~n", [Procs]),
-    lists:map(
-      fun ({Pid, _}) when is_pid(Pid) ->
-	      trace_exit(Table, Pid, TS)
-      end,
-      Procs),
-    erase(),
+    _ = lists:map(fun ({Pid, _}) when is_pid(Pid) ->
+                          trace_exit(Table, Pid, TS)
+                  end, Procs),
+    _ = erase(),
     ok.
 
 
@@ -2047,7 +2045,7 @@ trace_exit(Table, Pid, TS) ->
 	[] ->
 	    ok;
 	[_ | _] = Stack ->
-	    trace_return_to_int(Table, Pid, undefined, TS, Stack),
+	    _ = trace_return_to_int(Table, Pid, undefined, TS, Stack),
 	    ok
     end,
     ok.
@@ -2173,7 +2171,7 @@ trace_clock(_Table, _Pid, _T,
 	    [[{suspend, _}], [{suspend, _}] | _]=_Stack, _Clock) ->
     ?dbg(9, "trace_clock(Table, ~w, ~w, ~w, ~w)~n",
 	 [_Pid, _T, _Stack, _Clock]),
-    void;
+    ok;
 trace_clock(Table, Pid, T, 
 	    [[{garbage_collect, TS0}], [{suspend, _}]], Clock) ->
     trace_clock_1(Table, Pid, T, TS0, undefined, garbage_collect, Clock);
@@ -2188,7 +2186,7 @@ trace_clock(Table, Pid, T, [[{Func0, TS0}], [{Func1, _} | _] | _], Clock) ->
 trace_clock(Table, Pid, T, [[{Func0, TS0}]], Clock) ->
     trace_clock_1(Table, Pid, T, TS0, undefined, Func0, Clock);
 trace_clock(_, _, _, [], _) ->
-    void.
+    ok.
 
 trace_clock_1(Table, Pid, _, _, Caller, suspend, #clocks.own) ->
     clock_add(Table, {Pid, Caller, suspend}, #clocks.own, 0);
@@ -2202,7 +2200,7 @@ trace_clock_1(Table, Pid, T, TS, Caller, Func, Clock) ->
 
 clock_add(Table, Id, Clock, T) ->
     ?dbg(1, "clock_add(Table, ~w, ~w, ~w)~n", [Id, Clock, T]),
-    try ets:update_counter(Table, Id, {Clock, T})
+    try ets:update_counter(Table, Id, {Clock, T}), ok
     catch
 	error:badarg ->
 	    ets:insert(Table, #clocks{id = Id}),
@@ -2211,7 +2209,7 @@ clock_add(Table, Id, Clock, T) ->
 	       true -> ?dbg(0, "Negative counter value ~p ~p ~p ~p~n",
 			  [X, Id, Clock, T])
 	    end,
-	    X
+	    ok
     end.
 
 clocks_add(Table, #clocks{id = Id} = Clocks) ->
diff --git a/lib/tools/src/lcnt.erl b/lib/tools/src/lcnt.erl
index 78407a651a..23d66b084e 100644
--- a/lib/tools/src/lcnt.erl
+++ b/lib/tools/src/lcnt.erl
@@ -23,67 +23,57 @@
 -author("Björn-Egil Dahlberg").
 
 %% gen_server callbacks
--export([
-	init/1,
-	handle_call/3,
-	handle_cast/2,
-	handle_info/2,
-	terminate/2,
-	code_change/3
-	]).
+-export([init/1,
+         handle_call/3,
+         handle_cast/2,
+         handle_info/2,
+         terminate/2,
+         code_change/3]).
 
 %% start/stop
--export([
-	start/0,
-	stop/0
-	]).
+-export([start/0,
+         stop/0]).
 
 %% erts_debug:lock_counters api
--export([
-	rt_collect/0,
-	rt_collect/1,
-	rt_clear/0,
-	rt_clear/1,
-	rt_opt/1,
-	rt_opt/2
-    ]).
+-export([rt_collect/0,
+         rt_collect/1,
+         rt_clear/0,
+         rt_clear/1,
+         rt_opt/1,
+         rt_opt/2]).
 
 
 %% gen_server call api
--export([
-	raw/0,
-	collect/0,
-	collect/1,
-	clear/0,
-	clear/1,
-	conflicts/0,
-	conflicts/1,
-	locations/0,
-	locations/1,
-	inspect/1,
-	inspect/2,
-	histogram/1,
-	histogram/2,
-	information/0,
-	swap_pid_keys/0,
-	% set options
-	set/1,
-	set/2,
-
-	load/1,
-	save/1
-	]).
+-export([raw/0,
+         collect/0,
+         collect/1,
+         clear/0,
+         clear/1,
+         conflicts/0,
+         conflicts/1,
+         locations/0,
+         locations/1,
+         inspect/1,
+         inspect/2,
+         histogram/1,
+         histogram/2,
+         information/0,
+         swap_pid_keys/0,
+         % set options
+         set/1,
+         set/2,
+
+         load/1,
+         save/1]).
 
 %% convenience
--export([
-	apply/3,
-	apply/2,
-	apply/1,
-	all_conflicts/0,
-	all_conflicts/1,
-	pid/2, pid/3,
-	port/1, port/2
-    ]).
+-export([apply/3,
+         apply/2,
+         apply/1,
+         all_conflicts/0,
+         all_conflicts/1,
+         pid/2, pid/3,
+         port/1, port/2]).
 
 -define(version, "1.0").
 
@@ -135,6 +125,13 @@ start()  -> gen_server:start({local, ?MODULE}, ?MODULE, [], []).
 stop()   -> gen_server:call(?MODULE, stop, infinity).
 init([]) -> {ok, #state{ locks = [], duration = 0 } }.
 
+start_internal() ->
+    case start() of
+        {ok,_} -> ok;
+        {error, {already_started,_}} -> ok;
+        Error -> Error
+    end.
+
 %% -------------------------------------------------------------------- %%
 %%
 %% API erts_debug:lock_counters
@@ -184,7 +181,7 @@ raw()                -> call(raw).
 set(Option, Value)   -> call({set, Option, Value}).
 set({Option, Value}) -> call({set, Option, Value}).
 save(Filename)       -> call({save, Filename}).
-load(Filename)       -> start(), call({load, Filename}).
+load(Filename)       -> ok = start_internal(), call({load, Filename}).
 
 call(Msg) -> gen_server:call(?MODULE, Msg, infinity).
 
@@ -195,7 +192,7 @@ call(Msg) -> gen_server:call(?MODULE, Msg, infinity).
 %% -------------------------------------------------------------------- %%
 
 apply(M,F,As) when is_atom(M), is_atom(F), is_list(As) ->
-    lcnt:start(),
+    ok = start_internal(),
     Opt = lcnt:rt_opt({copy_save, true}),
     lcnt:clear(),
     Res = erlang:apply(M,F,As),
@@ -207,7 +204,7 @@ apply(Fun) when is_function(Fun) ->
     lcnt:apply(Fun, []).
 
 apply(Fun, As) when is_function(Fun) ->
-    lcnt:start(),
+    ok = start_internal(),
     Opt = lcnt:rt_opt({copy_save, true}),
     lcnt:clear(),
     Res = erlang:apply(Fun, As),
diff --git a/lib/tools/src/tags.erl b/lib/tools/src/tags.erl
index 2bc1865503..b833d96c19 100644
--- a/lib/tools/src/tags.erl
+++ b/lib/tools/src/tags.erl
@@ -101,7 +101,7 @@ files(Files, Options) ->
     case open_out(Options) of
 	{ok, Os} ->
 	    files_loop(Files, Os),
-	    close_out(Os),
+	    ok = close_out(Os),
 	    ok;
 	_ ->
 	    error
@@ -169,7 +169,7 @@ filename(Name, Os) ->
     case file:open(Name, [read]) of
 	{ok, Desc} ->
 	    Acc = module(Desc, [], [], {1, 0}),
-	    file:close(Desc),
+	    ok = file:close(Desc),
 	    genout(Os, Name, Acc),
 	    ok;
 	_ ->
diff --git a/lib/tools/src/xref_base.erl b/lib/tools/src/xref_base.erl
index 70eb107781..4322943c59 100644
--- a/lib/tools/src/xref_base.erl
+++ b/lib/tools/src/xref_base.erl
@@ -696,7 +696,7 @@ do_add_module({Dir, Basename}, AppName, Builtins, Verbose, Warnings, State) ->
     File = filename:join(Dir, Basename),
     {ok, M, Bad, NewState} =
 	do_add_module1(Dir, File, AppName, Builtins, Verbose, Warnings, State),
-    filter(fun({Tag,B}) -> warnings(Warnings, Tag, [[File,B]]) end, Bad),
+    _ = filter(fun({Tag,B}) -> warnings(Warnings, Tag, [[File,B]]) end, Bad),
     {ok, M, NewState}.
 
 do_add_module1(Dir, File, AppName, Builtins, Verbose, Warnings, State) ->
@@ -1727,7 +1727,7 @@ pack(T) ->
     NT = pack1(T),
     %% true = T =:= NT,
     %% io:format("erasing ~p elements...~n", [length(erase())]),
-    erase(), % wasting heap (and time)...
+    _ = erase(), % wasting heap (and time)...
     foreach(fun({K,V}) -> put(K, V) end, PD),
     NT.