path: root/lib/compiler/test/warnings_SUITE.erl

%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2003-2013. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%%     http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
-module(warnings_SUITE).

%%-define(STANDALONE, true).

-ifdef(STANDALONE).
-define(line, put(line, ?LINE), ).
-define(config(X,Y), foo).
-define(privdir, "warnings_SUITE_priv").
-define(t, test_server).
-else.
-include_lib("common_test/include/ct.hrl").
-define(datadir, proplists:get_value(data_dir, Conf)).
-define(privdir, proplists:get_value(priv_dir, Conf)).
-endif.

-export([all/0, suite/0,groups/0,init_per_suite/1, end_per_suite/1, 
	 init_per_group/2,end_per_group/2,
	 init_per_testcase/2,end_per_testcase/2]).

-export([pattern/1,pattern2/1,pattern3/1,pattern4/1,
	 guard/1,bad_arith/1,bool_cases/1,bad_apply/1,
         files/1,effect/1,bin_opt_info/1,bin_construction/1,
	 comprehensions/1,maps/1,maps_bin_opt_info/1,
         redundant_boolean_clauses/1,
	 latin1_fallback/1,underscore/1,no_warnings/1]).

init_per_testcase(_Case, Config) ->
    Config.

end_per_testcase(_Case, _Config) ->
    ok.

suite() ->
    [{ct_hooks,[ts_install_cth]},
     {timetrap,{minutes,2}}].

all() -> 
    test_lib:recompile(?MODULE),
    [{group,p}].

groups() -> 
    [{p,test_lib:parallel(),
      [pattern,pattern2,pattern3,pattern4,guard,
       bad_arith,bool_cases,bad_apply,files,effect,
       bin_opt_info,bin_construction,comprehensions,maps,
       maps_bin_opt_info,
       redundant_boolean_clauses,latin1_fallback,
       underscore,no_warnings]}].

init_per_suite(Config) ->
    Config.

end_per_suite(_Config) ->
    ok.

init_per_group(_GroupName, Config) ->
    Config.

end_per_group(_GroupName, Config) ->
    Config.


pattern(Config) when is_list(Config) ->
    %% Test warnings generated by v3_core.
    Ts = [{pattern,
           <<"%% Just a comment here.
              f(a={glurf,2}=A) -> A.

              g(A) ->
                 case A of
                   a=[_|_] -> error;
                   Other -> true
                 end.

              foo(X) ->
                 a = {nisse,b} = X.
           ">>,
	   [warn_unused_vars],
	   {warnings,
	    [{2,v3_core,nomatch},
	     {6,v3_core,nomatch},
	     {11,v3_core,nomatch} ] }}],
    ?line [] = run(Config, Ts),
    ok.

pattern2(Config) when is_list(Config) ->
    %% Test warnings generated by sys_core_fold.
    %% If we disable Core Erlang optimizations, we expect that
    %% v3_kernel should generate some of the warnings.
    Source = <<"f(A) -> ok;
              f(B) -> error.
	      t(A, B, C) ->
	        case {A,B,C} of
	          {a,B} -> ok;
	          {_,B} -> ok
                end.
           ">>,

    %% Test warnings from sys_core_fold.
    Ts = [{pattern2,
	   Source,
	   [nowarn_unused_vars],
	   {warnings,[{2,sys_core_fold,{nomatch_shadow,1}},
		      {4,sys_core_fold,no_clause_match},
		      {5,sys_core_fold,nomatch_clause_type},
		      {6,sys_core_fold,nomatch_clause_type}]}}],
    ?line [] = run(Config, Ts),

    %% Disable Core Erlang optimizations. v3_kernel should produce
    %% a warning for the clause that didn't match.
    Ts2 = [{pattern2,
	    Source,
	    [nowarn_unused_vars,no_copt],
	    {warnings,
	     [{2,v3_kernel,{nomatch_shadow,1}}]}}],
    ?line [] = run(Config, Ts2),
    ok.

pattern3(Config) when is_list(Config) ->
    %% Test warnings generated by the pattern matching compiler
    %% in v3_kernel.

    Ts = [{pattern3,
	   <<"
	    f({A,_}) -> {ok,A};
	    f([_|_]=B) -> {ok,B};
	    f({urk,nisse}) -> urka_glurka.
           ">>,
	   [nowarn_unused_vars],
	   {warnings,
	    [{4,v3_kernel,{nomatch_shadow,2}}]}}],
    ?line [] = run(Config, Ts),

    ok.

pattern4(Config) when is_list(Config) ->
    %% Test warnings for clauses that cannot possibly match.

    Ts = [{pattern4,
	   <<"
             t() ->
               case true of 
                 false -> a;
                 true -> b
               end.

             fi() ->
               case true of 
                 false -> a;
                 false -> b
               end,
               case true of 
                 true -> a;
                 true -> b;
                 X -> X
               end,
               case boolean of 
                 true -> a;
                 false -> b
               end.
             int() ->
               case 42 of
                 [a|b] -> no;
                 <<1>> -> no;
                 <<X>> -> no;
                 17 -> no;
                 [] -> no;
                 a -> no;
                 {a,b,c} -> no
               end.
             tuple() ->
               case {x,y,z} of
                 \"xyz\" -> no;
                 [a|b] -> no;
                 <<1>> -> no;
                 <<X>> -> no;
                 17 -> no;
                 [] -> no;
                 a -> no;
                 {a,b,c} -> no;
                 {x,y} -> no
               end.
           ">>,
	   [nowarn_unused_vars],
	   {warnings,
	    [{9,sys_core_fold,no_clause_match},
             {11,sys_core_fold,nomatch_shadow},
             {15,sys_core_fold,nomatch_shadow},
	     {18,sys_core_fold,no_clause_match},
	     {23,sys_core_fold,no_clause_match},
	     {33,sys_core_fold,no_clause_match}
	    ]}}],
    ?line [] = run(Config, Ts),

    ok.

guard(Config) when is_list(Config) ->
    %% Test warnings for false guards.

    Ts = [{guard,
	   <<"
              t(A, B) when element(x, dum) -> ok.

              tt(A, B) when 1 == 2 -> ok.

              ttt() when element(x, dum) -> ok.

              t4(T, F) when element({F}, T) -> ok.
              t5(T, F) when element([F], T) -> ok.
              t6(Pos, F) when element(Pos, [F]) -> ok.
              t7(Pos) when element(Pos, []) -> ok.
           ">>,
	   [nowarn_unused_vars],
	   {warnings,
	    [{2,sys_core_fold,no_clause_match},
	     {2,sys_core_fold,nomatch_guard},
	     {2,sys_core_fold,{eval_failure,badarg}},
	     {4,sys_core_fold,no_clause_match},
	     {4,sys_core_fold,nomatch_guard},
	     {6,sys_core_fold,no_clause_match},
	     {6,sys_core_fold,nomatch_guard},
	     {6,sys_core_fold,{eval_failure,badarg}},
	     {8,sys_core_fold,no_clause_match},
	     {8,sys_core_fold,nomatch_guard},
	     {8,sys_core_fold,{eval_failure,badarg}},
	     {9,sys_core_fold,no_clause_match},
	     {9,sys_core_fold,nomatch_guard},
	     {9,sys_core_fold,{eval_failure,badarg}},
	     {10,sys_core_fold,no_clause_match},
	     {10,sys_core_fold,nomatch_guard},
	     {10,sys_core_fold,{eval_failure,badarg}},
	     {11,sys_core_fold,no_clause_match},
	     {11,sys_core_fold,nomatch_guard},
	     {11,sys_core_fold,{eval_failure,badarg}}
	    ]}}],
    ?line [] = run(Config, Ts),

    ok.

bad_arith(Config) when is_list(Config) ->
    Ts = [{bad_arith,
           <<"f() ->
                if
                  a + 3 > 3 -> ok;
          	 true -> error
              end.

              g(A) ->
                if
                  is_integer(A), a + 3 > 3 -> ok;
                  a + 3 > 42, is_integer(A) -> ok;
          	 true -> error
              end.

              h(A) ->
                a + 3 + A.
           ">>,
	   [],
	   {warnings,
	    [{3,sys_core_fold,nomatch_guard},
	     {3,sys_core_fold,{eval_failure,badarith}},
	     {9,sys_core_fold,nomatch_guard},
	     {9,sys_core_fold,{eval_failure,badarith}},
	     {9,sys_core_fold,{no_effect,{erlang,is_integer,1}}},
	     {10,sys_core_fold,nomatch_guard},
	     {10,sys_core_fold,{eval_failure,badarith}},
	     {15,sys_core_fold,{eval_failure,badarith}}
	    ] }}],
    [] = run(Config, Ts),
    ok.

bool_cases(Config) when is_list(Config) ->
    Ts = [{bool_cases,
	   <<"
            f(A, B) ->
               case A > B of
                 true -> true;
                 false -> false;
                 Other -> {error,not_bool}
               end.

            g(A, B) ->
               case A =/= B of
                 false -> false;
                 true -> true;
                 Other -> {error,not_bool}
               end.

	    h(Bool) ->
              case not Bool of
	        maybe -> strange;
	        false -> ok;
	        true -> error
            end.
           ">>,
	   [nowarn_unused_vars],
	   {warnings,
	    [{6,sys_core_fold,nomatch_shadow},
	     {13,sys_core_fold,nomatch_shadow},
	     {18,sys_core_fold,nomatch_clause_type} ]} }],
    ?line [] = run(Config, Ts),
    ok.

bad_apply(Config) when is_list(Config) ->
    Ts = [{bad_apply,
	   <<"
             t(1) -> 42:42();
             t(2) -> erlang:42();
             t(3) -> 42:start();
             t(4) -> []:start();
             t(5) -> erlang:[]().
           ">>,
	   [],
	   {warnings,
	    [{2,v3_kernel,bad_call},
	     {3,v3_kernel,bad_call},
	     {4,v3_kernel,bad_call},
	     {5,v3_kernel,bad_call},
	     {6,v3_kernel,bad_call}]}}],
    ?line [] = run(Config, Ts),

    %% Also verify that the generated code generates the correct error.
    ?line try erlang:42() of
	      _ -> ct:fail(should_fail)
	  catch
	      error:badarg -> ok
	  end,
    ok.

files(Config) when is_list(Config) ->
    Ts = [{files_1,
	   <<"
              -file(\"file1\", 14).

              t1() ->
                  1/0.

              -file(\"file2\", 7).

              t2() ->
                  1/0.
           ">>,
           [],
           {warnings,
            [{"file1",[{17,sys_core_fold,{eval_failure,badarith}}]},
             {"file2",[{10,sys_core_fold,{eval_failure,badarith}}]}]}}],

    ?line [] = run(Config, Ts),
    ok.

%% Test warnings for term construction and BIF calls in effect context.
effect(Config) when is_list(Config) ->
    Ts = [{effect,
	   <<"
             t(X) ->
               case X of
              	warn_lc ->
              	    [is_integer(Z) || Z <- [1,2,3]];
              	warn_lc_2 ->
              	    [{error,Z} || Z <- [1,2,3]];
              	warn_lc_3 ->
              	    [{error,abs(Z)} || Z <- [1,2,3]];
              	no_warn_lc ->
              	    [put(last_integer, Z) || Z <- [1,2,3]]; %no warning
              	unused_tuple_literal ->
              	    {a,b,c};
              	unused_list_literal ->
              	    [1,2,3,4];
              	unused_integer ->
              	    42;
              	unused_arith ->
              	    X*X;
              	nested ->
              	    [{ok,node(),?MODULE:foo(),self(),[time(),date()],time()},
              	     is_integer(X)];
              	unused_bit_syntax ->
              	    <<X:8>>;
              	unused_fun ->
              	    fun() -> {ok,X} end;
		unused_named_fun ->
		    fun F(0) -> 1;
                        F(N) -> N*F(N-1)
                    end;
              	unused_atom ->
              	    ignore;				%no warning
              	unused_nil ->
              	    [];					%no warning
                comp_op ->
                    X =:= 2;
                cookie ->
                    erlang:get_cookie();
		result_ignore ->
                    _ = list_to_integer(X);
                warn_lc_4 ->
                    %% No warning because of assignment to _.
                    [_ = abs(Z) || Z <- [1,2,3]]
               end,
               ok.

             %% No warnings should be generated in the following functions.
             m1(X, Sz) ->
                if
             	  Sz =:= 0 -> X = 0;
             	  true -> ok
                end,
                ok.

             m2(X, Sz) ->
                if
             	  Sz =:= 0 -> X = {a,Sz};
             	  true -> ok
                end,
                ok.

             m3(X, Sz) ->
                if
             	  Sz =:= 0 -> X = [a,Sz];
             	  true -> ok
                end,
                ok.

             m4(X, Sz, Var) ->
                if
             	  Sz =:= 0 -> X = Var;
             	  true -> ok
                end,
                ok.

             m5(X, Sz) ->
                if
             	   Sz =:= 0 -> X = {a,b,c};
             	   true -> ok
                end,
                ok.

             m6(X, Sz) ->
                if
             	  Sz =:= 0 -> X = {a,Sz,[1,2,3]};
             	  true -> ok
                end,
                ok.

             m7(X, Sz) ->
                if
             	  Sz =:= 0 -> X = {a,Sz,[1,2,3],abs(Sz)};
             	  true -> ok
                end,
                ok.

             m8(A, B) ->
                case {A,B} of
                  V -> V
                end,
                ok.

             m9(Bs) ->
                [{B,ok} = {B,foo:bar(B)} || B <- Bs],
                ok.

             m10(ConfigTableSize) ->
               case ConfigTableSize of
                 apa ->
                   CurrentConfig = {id(camel_phase3),id(sms)},
                   case CurrentConfig of
                     {apa, bepa} -> ok;
		     _ -> ok
	           end
               end,
               ok.

             id(I) -> I.
             ">>,
	   [],
	   {warnings,[{5,sys_core_fold,{no_effect,{erlang,is_integer,1}}},
		      {7,sys_core_fold,useless_building},
		      {9,sys_core_fold,result_ignored},
		      {9,sys_core_fold,useless_building},
		      {13,sys_core_fold,useless_building},
		      {15,sys_core_fold,useless_building},
		      {17,sys_core_fold,useless_building},
		      {19,sys_core_fold,result_ignored},
		      {21,sys_core_fold,useless_building},
		      {21,sys_core_fold,{no_effect,{erlang,date,0}}},
		      {21,sys_core_fold,{no_effect,{erlang,node,0}}},
		      {21,sys_core_fold,{no_effect,{erlang,self,0}}},
		      {21,sys_core_fold,{no_effect,{erlang,time,0}}},
		      {22,sys_core_fold,useless_building},
		      {22,sys_core_fold,{no_effect,{erlang,is_integer,1}}},
		      {24,sys_core_fold,useless_building},
		      {26,sys_core_fold,useless_building},
		      {28,sys_core_fold,useless_building},
		      {36,sys_core_fold,{no_effect,{erlang,'=:=',2}}},
		      {38,sys_core_fold,{no_effect,{erlang,get_cookie,0}}}]}}],
    ?line [] = run(Config, Ts),
    ok.

bin_opt_info(Config) when is_list(Config) ->
    Code = <<"
             t1(Bin) ->
               case Bin of
	         _ when byte_size(Bin) > 20 -> erlang:error(too_long);
                 <<_,T/binary>> -> t1(T);
	         <<>> -> ok
             end.

             t2(<<_,T/bytes>>) ->
               split_binary(T, 4).
           ">>,
    Ts1 = [{bsm1,
	    Code,
	    [bin_opt_info],
	    {warnings,
	     [{4,sys_core_fold,orig_bin_var_used_in_guard},
	      {5,beam_bsm,{no_bin_opt,{{t1,1},no_suitable_bs_start_match}}},
	      {9,beam_bsm,{no_bin_opt,
			   {binary_used_in,{extfunc,erlang,split_binary,2}}}} ]}}],
    ?line [] = run(Config, Ts1),

    %% For coverage: don't give the bin_opt_info option.
    Ts2 = [{bsm2,
	    Code,
	    [],
	    []}],
    ?line [] = run(Config, Ts2),
    ok.

bin_construction(Config) when is_list(Config) ->
    Ts = [{bin_construction,
	   <<"
             t() ->
                 Bin = <<1,2,3>>,
                 <<Bin:4/binary>>.

             x() ->
                 Bin = <<1,2,3,7:4>>,
                 <<Bin/binary>>.
           ">>,
	   [],
	   {warnings,[{4,sys_core_fold,embedded_binary_size},
		      {8,sys_core_fold,{embedded_unit,8,28}}]}}],
    ?line [] = run(Config, Ts),
    
    ok.

comprehensions(Config) when is_list(Config) ->
    Ts = [{tautologic_guards,
           <<"
             f() -> [ true || true ].
             g() -> << <<1>> || true >>.
           ">>,
           [], []}],
    run(Config, Ts),
    ok.

maps(Config) when is_list(Config) ->
    Ts = [{bad_map,
           <<"
             t() ->
                 case maybe_map of
                     #{} -> ok;
                     not_map -> error
                 end.
             x() ->
                 case true of
                     #{}  -> error;
                     true -> ok
                 end.
           ">>,
           [],
           {warnings,[{3,sys_core_fold,no_clause_match},
                      {9,sys_core_fold,nomatch_clause_type}]}},
	   {bad_map_src1,
           <<"
             t() ->
		 M = {a,[]},
		 {'EXIT',{badarg,_}} = (catch(M#{ a => 1 })),
		 ok.
           ">>,
           [],
	   {warnings,[{4,sys_core_fold,{eval_failure,badmap}}]}},
	   {bad_map_src2,
           <<"
             t() ->
		 M = id({a,[]}),
		 {'EXIT',{badarg,_}} = (catch(M#{ a => 1})),
		 ok.
	     id(I) -> I.
           ">>,
	   [inline],
	    []},
	   {bad_map_src3,
           <<"
             t() ->
		 {'EXIT',{badarg,_}} = (catch <<>>#{ a := 1}),
		 ok.
           ">>,
           [],
	   {warnings,[{3,v3_core,badmap}]}},
	   {ok_map_literal_key,
           <<"
             t() ->
		 V = id(1),
		 M = id(#{ <<$h,$i>> => V }),
		 V = case M of
		    #{ <<0:257>> := Val } -> Val;
		    #{ <<$h,$i>> := Val } -> Val
		 end,
		 ok.
	     id(I) -> I.
           ">>,
           [],
	   []}],
    run(Config, Ts),
    ok.

maps_bin_opt_info(Config) when is_list(Config) ->
    Ts = [{map_bsm,
           <<"
             t1(<<0:8,7:8,T/binary>>,#{val := I}=M) ->
                 t1(T, M#{val := I+1});
             t1(<<_:8>>,M) ->
                 M.
           ">>,
           [bin_opt_info],
           {warnings,[{2,beam_bsm,bin_opt}]}}],
    [] = run(Config, Ts),
    ok.

redundant_boolean_clauses(Config) when is_list(Config) ->
    Ts = [{redundant_boolean_clauses,
           <<"
             t(X) ->
                 case X == 0 of
                     false -> no;
                     false -> no;
                     true -> yes
                 end.
           ">>,
           [],
           {warnings,[{5,sys_core_fold,nomatch_shadow}]}}],
    run(Config, Ts),
    ok.

latin1_fallback(Conf) when is_list(Conf) ->
    DataDir = ?privdir,
    IncFile = filename:join(DataDir, "include_me.hrl"),
    file:write_file(IncFile, <<"%% ",246," in include file\n">>),
    Ts1 = [{latin1_fallback1,
	    %% Test that the compiler fall backs to latin-1 with
	    %% a warning if a file has no encoding and does not
	    %% contain correct UTF-8 sequences.
	    <<"%% Bj",246,"rn
              t(_) -> \"",246,"\";
              t(x) -> ok.
              ">>,
	    [],
	    {warnings,[{1,compile,reparsing_invalid_unicode},
		       {3,sys_core_fold,{nomatch_shadow,2}}]}}],
    [] = run(Conf, Ts1),

    Ts2 = [{latin1_fallback2,
	    %% Test that the compiler fall backs to latin-1 with
	    %% a warning if a file has no encoding and does not
	    %% contain correct UTF-8 sequences.
	    <<"

	      -include(\"include_me.hrl\").
              ">>,
	    [],
	    {warnings,[{1,compile,reparsing_invalid_unicode}]}
	   }],
    [] = run(Conf, Ts2),

    Ts3 = [{latin1_fallback3,
	    %% Test that the compiler fall backs to latin-1 with
	    %% a warning if a file has no encoding and does not
	    %% contain correct UTF-8 sequences.
	    <<"-ifdef(NOTDEFINED).
              t(_) -> \"",246,"\";
              t(x) -> ok.
              -endif.
              ">>,
	    [],
	    {warnings,[{2,compile,reparsing_invalid_unicode}]}}],
    [] = run(Conf, Ts3),

    ok.

underscore(Config) when is_list(Config) ->
    S0 = <<"f(A) ->
              _VAR1 = <<A>>,
              _VAR2 = {ok,A},
              _VAR3 = [A],
              ok.
	    g(A) ->
              _VAR1 = A/0,
              _VAR2 = date(),
	      ok.
            h() ->
               _VAR1 = fun() -> ok end,
	      ok.
            i(A) ->
               _VAR1 = #{A=>42},
	      ok.
	 ">>,
    Ts0 = [{underscore0,
	    S0,
	    [],
	    {warnings,[{2,sys_core_fold,useless_building},
		       {3,sys_core_fold,useless_building},
		       {4,sys_core_fold,useless_building},
		       {7,sys_core_fold,result_ignored},
		       {8,sys_core_fold,{no_effect,{erlang,date,0}}},
		       {11,sys_core_fold,useless_building},
		       {14,sys_core_fold,useless_building}
		      ]}}],
    [] = run(Config, Ts0),

    %% Replace all "_VAR<digit>" variables with a plain underscore.
    %% Now there should be no warnings.
    S1 = re:replace(S0, "_VAR\\d+", "_", [global]),
    io:format("~s\n", [S1]),
    Ts1 = [{underscore1,S1,[],[]}],
    [] = run(Config, Ts1),

    ok.

no_warnings(Config) when is_list(Config) ->
    Ts = [{no_warnings,
           <<"-record(r, {s=ordsets:new(),a,b}).

              a() ->
                R = #r{},			%No warning expected.
                {R#r.a,R#r.b}.

              b(X) ->
                T = true,
                Var = [X],			%No warning expected.
                case T of
	          false -> Var;
                  true -> []
                end.

              c() ->
                R0 = {r,\"abc\",undefined,os:timestamp()}, %No warning.
                case R0 of
	          {r,V1,_V2,V3} -> {r,V1,\"def\",V3}
                end.

              d(In0, Bool) ->
                {In1,Int} = case id(Bool) of
                              false -> {In0,0}
                            end,
                [In1,Int].

              id(I) -> I.
           ">>,
           [],
           []}],
    run(Config, Ts),
    ok.

%%%
%%% End of test cases.
%%%

run(Config, Tests) ->
    F = fun({N,P,Ws,E}, BadL) ->
                case catch run_test(Config, P, Ws) of
                    E -> 
                        BadL;
                    Bad -> 
                        ?t:format("~nTest ~p failed. Expected~n  ~p~n"
                                  "but got~n  ~p~n", [N, E, Bad]),
			fail()
                end
        end,
    lists:foldl(F, [], Tests).


%% Compiles a test module and returns the list of errors and warnings.

run_test(Conf, Test0, Warnings) ->
    Module = "warnings_"++test_lib:uniq(),
    Filename = Module ++ ".erl",
    ?line DataDir = ?privdir,
    Test = ["-module(", Module, "). ", Test0],
    ?line File = filename:join(DataDir, Filename),
    ?line Opts = [binary,export_all,return|Warnings],
    ?line ok = file:write_file(File, Test),

    %% Compile once just to print all warnings.
    ?line compile:file(File, [binary,export_all,report|Warnings]),

    %% Test result of compilation.
    ?line Res = case compile:file(File, Opts) of
		    {ok, _M, Bin, []} when is_binary(Bin) ->
			[];
		    {ok, _M, Bin, Ws0} when is_binary(Bin) ->
			%% We are not interested in warnings from
			%% erl_lint here.
			WsL = [{F,[W || {_,Mod,_}=W <- Ws, 
					Mod =/= erl_lint]} ||
				  {F,Ws} <- Ws0],
                        case WsL of 
                            [{_File,Ws}] -> {warnings, Ws};
                            _ -> list_to_tuple([warnings, WsL])
                        end
		end,
    file:delete(File),
    Res.

fail() ->
    ct:fail(failed).