%% -*- erlang-indent-level: 2 -*-
%%-----------------------------------------------------------------------
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2007-2011. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
-module(dialyzer_contracts).
-export([check_contract/2,
check_contracts/3,
contracts_without_fun/3,
contract_to_string/1,
get_invalid_contract_warnings/3,
get_contract_args/1,
get_contract_return/1,
get_contract_return/2,
%% get_contract_signature/1,
is_overloaded/1,
process_contract_remote_types/1,
store_tmp_contract/5]).
-export_type([file_contract/0, plt_contracts/0]).
%%-----------------------------------------------------------------------
-include("dialyzer.hrl").
%%-----------------------------------------------------------------------
%% Types used in other parts of the system below
%%-----------------------------------------------------------------------
-type file_contract() :: {file_line(), #contract{}}.
-type plt_contracts() :: [{mfa(), #contract{}}]. % actually, an orddict()
%%-----------------------------------------------------------------------
%% Internal record for contracts whose components have not been processed
%% to expand records and/or remote types that they might contain.
%%-----------------------------------------------------------------------
-type tmp_contract_fun() :: fun((set(), dict()) -> contract_pair()).
-record(tmp_contract, {contract_funs = [] :: [tmp_contract_fun()],
forms = [] :: [{_, _}]}).
%%-----------------------------------------------------------------------
%%-define(DEBUG, true).
-ifdef(DEBUG).
-define(debug(X__, Y__), io:format(X__, Y__)).
-else.
-define(debug(X__, Y__), ok).
-endif.
%%-----------------------------------------------------------------------
-spec get_contract_return(#contract{}) -> erl_types:erl_type().
get_contract_return(#contract{contracts = Cs, args = GenArgs}) ->
process_contracts(Cs, GenArgs).
-spec get_contract_return(#contract{}, [erl_types:erl_type()]) -> erl_types:erl_type().
get_contract_return(#contract{contracts = Cs}, Args) ->
process_contracts(Cs, Args).
-spec get_contract_args(#contract{}) -> [erl_types:erl_type()].
get_contract_args(#contract{args = Args}) ->
Args.
-spec get_contract_signature(#contract{}) -> erl_types:erl_type().
get_contract_signature(#contract{contracts = Cs, args = GeneralDomain}) ->
Range = process_contracts(Cs, GeneralDomain),
erl_types:t_fun(GeneralDomain, Range).
-spec is_overloaded(#contract{}) -> boolean().
is_overloaded(#contract{contracts = Cs}) ->
case Cs of
[_] -> true;
[_,_|_] -> false
end.
-spec contract_to_string(#contract{}) -> string().
contract_to_string(#contract{forms = Forms}) ->
contract_to_string_1(Forms).
contract_to_string_1([{Contract, []}]) ->
strip_fun(erl_types:t_form_to_string(Contract));
contract_to_string_1([{Contract, []}|Rest]) ->
strip_fun(erl_types:t_form_to_string(Contract)) ++ "\n ; "
++ contract_to_string_1(Rest);
contract_to_string_1([{Contract, Constraints}]) ->
strip_fun(erl_types:t_form_to_string(Contract)) ++ " when "
++ constraints_to_string(Constraints);
contract_to_string_1([{Contract, Constraints}|Rest]) ->
strip_fun(erl_types:t_form_to_string(Contract)) ++ " when "
++ constraints_to_string(Constraints) ++ ";" ++
contract_to_string_1(Rest).
strip_fun("fun(" ++ String) ->
butlast(String).
butlast([]) -> [];
butlast([_]) -> [];
butlast([H|T]) -> [H|butlast(T)].
constraints_to_string([]) ->
"";
constraints_to_string([{type, _, constraint, [{atom, _, What}, Types]}]) ->
atom_to_list(What) ++ "(" ++
sequence([erl_types:t_form_to_string(T) || T <- Types], ",") ++ ")";
constraints_to_string([{type, _, constraint, [{atom, _, What}, Types]}|Rest]) ->
atom_to_list(What) ++ "(" ++
sequence([erl_types:t_form_to_string(T) || T <- Types], ",")
++ "), " ++ constraints_to_string(Rest).
sequence([], _Delimiter) -> "";
sequence([H], _Delimiter) -> H;
sequence([H|T], Delimiter) -> H ++ Delimiter ++ sequence(T, Delimiter).
-spec process_contract_remote_types(dialyzer_codeserver:codeserver()) ->
dialyzer_codeserver:codeserver().
process_contract_remote_types(CodeServer) ->
{TmpContractDict, TmpCallbackDict} =
dialyzer_codeserver:get_temp_contracts(CodeServer),
ExpTypes = dialyzer_codeserver:get_exported_types(CodeServer),
RecordDict = dialyzer_codeserver:get_records(CodeServer),
ContractFun =
fun({_M, _F, _A}, {File, #tmp_contract{contract_funs = CFuns, forms = Forms}}) ->
NewCs = [CFun(ExpTypes, RecordDict) || CFun <- CFuns],
Args = general_domain(NewCs),
{File, #contract{contracts = NewCs, args = Args, forms = Forms}}
end,
ModuleFun =
fun(_ModuleName, ContractDict) ->
dict:map(ContractFun, ContractDict)
end,
NewContractDict = dict:map(ModuleFun, TmpContractDict),
NewCallbackDict = dict:map(ModuleFun, TmpCallbackDict),
dialyzer_codeserver:finalize_contracts(NewContractDict, NewCallbackDict,
CodeServer).
-spec check_contracts([{mfa(), file_contract()}],
dialyzer_callgraph:callgraph(), dict()) -> plt_contracts().
check_contracts(Contracts, Callgraph, FunTypes) ->
FoldFun =
fun(Label, Type, NewContracts) ->
case dialyzer_callgraph:lookup_name(Label, Callgraph) of
{ok, {M,F,A} = MFA} ->
case orddict:find(MFA, Contracts) of
{ok, {_FileLine, Contract}} ->
case check_contract(Contract, Type) of
ok ->
case erl_bif_types:is_known(M, F, A) of
true ->
%% Disregard the contracts since
%% this is a known function.
NewContracts;
false ->
[{MFA, Contract}|NewContracts]
end;
{error, _Error} -> NewContracts
end;
error -> NewContracts
end;
error -> NewContracts
end
end,
dict:fold(FoldFun, [], FunTypes).
%% Checks all components of a contract
-spec check_contract(#contract{}, erl_types:erl_type()) -> 'ok' | {'error', term()}.
check_contract(#contract{contracts = Contracts}, SuccType) ->
try
Contracts1 = [{Contract, insert_constraints(Constraints, dict:new())}
|| {Contract, Constraints} <- Contracts],
Contracts2 = [erl_types:t_subst(Contract, Dict)
|| {Contract, Dict} <- Contracts1],
GenDomains = [erl_types:t_fun_args(C) || C <- Contracts2],
case check_domains(GenDomains) of
error ->
{error, {overlapping_contract, []}};
ok ->
InfList = [erl_types:t_inf(Contract, SuccType, opaque)
|| Contract <- Contracts2],
case check_contract_inf_list(InfList, SuccType) of
{error, _} = Invalid -> Invalid;
ok -> check_extraneous(Contracts2, SuccType)
end
end
catch
throw:{error, _} = Error -> Error
end.
check_domains([_]) -> ok;
check_domains([Dom|Doms]) ->
Fun = fun(D) ->
erl_types:any_none_or_unit(erl_types:t_inf_lists(Dom, D, opaque))
end,
case lists:all(Fun, Doms) of
true -> check_domains(Doms);
false -> error
end.
%% Allow a contract if one of the overloaded contracts is possible.
%% We used to be more strict, e.g., all overloaded contracts had to be
%% possible.
check_contract_inf_list([FunType|Left], SuccType) ->
FunArgs = erl_types:t_fun_args(FunType),
case lists:any(fun erl_types:t_is_none_or_unit/1, FunArgs) of
true -> check_contract_inf_list(Left, SuccType);
false ->
STRange = erl_types:t_fun_range(SuccType),
case erl_types:t_is_none_or_unit(STRange) of
true -> ok;
false ->
Range = erl_types:t_fun_range(FunType),
case erl_types:t_is_none(erl_types:t_inf(STRange, Range, opaque)) of
true -> check_contract_inf_list(Left, SuccType);
false -> ok
end
end
end;
check_contract_inf_list([], _SuccType) ->
{error, invalid_contract}.
check_extraneous([], _SuccType) -> ok;
check_extraneous([C|Cs], SuccType) ->
case check_extraneous_1(C, SuccType) of
ok -> check_extraneous(Cs, SuccType);
Error -> Error
end.
check_extraneous_1(Contract, SuccType) ->
CRngs = erl_types:t_elements(erl_types:t_fun_range(Contract)),
STRng = erl_types:t_fun_range(SuccType),
?debug("CR = ~p\nSR = ~p\n", [CRngs, STRng]),
case [CR || CR <- CRngs, erl_types:t_is_none(erl_types:t_inf(CR, STRng, opaque))] of
[] -> ok;
CRs -> {error, {extra_range, erl_types:t_sup(CRs), STRng}}
end.
%% This is the heart of the "range function"
-spec process_contracts([contract_pair()], [erl_types:erl_type()]) -> erl_types:erl_type().
process_contracts(OverContracts, Args) ->
process_contracts(OverContracts, Args, erl_types:t_none()).
process_contracts([OverContract|Left], Args, AccRange) ->
NewAccRange =
case process_contract(OverContract, Args) of
error -> AccRange;
{ok, Range} -> erl_types:t_sup(AccRange, Range)
end,
process_contracts(Left, Args, NewAccRange);
process_contracts([], _Args, AccRange) ->
AccRange.
-spec process_contract(contract_pair(), [erl_types:erl_type()]) -> 'error' | {'ok', erl_types:erl_type()}.
process_contract({Contract, Constraints}, CallTypes0) ->
CallTypesFun = erl_types:t_fun(CallTypes0, erl_types:t_any()),
ContArgsFun = erl_types:t_fun(erl_types:t_fun_args(Contract),
erl_types:t_any()),
?debug("Instance: Contract: ~s\n Arguments: ~s\n",
[erl_types:t_to_string(ContArgsFun),
erl_types:t_to_string(CallTypesFun)]),
case solve_constraints(ContArgsFun, CallTypesFun, Constraints) of
{ok, VarDict} ->
{ok, erl_types:t_subst(erl_types:t_fun_range(Contract), VarDict)};
error -> error
end.
solve_constraints(Contract, Call, Constraints) ->
%% First make sure the call follows the constraints
CDict = insert_constraints(Constraints, dict:new()),
Contract1 = erl_types:t_subst(Contract, CDict),
%% Just a safe over-approximation.
%% TODO: Find the types for type variables properly
ContrArgs = erl_types:t_fun_args(Contract1),
CallArgs = erl_types:t_fun_args(Call),
InfList = erl_types:t_inf_lists(ContrArgs, CallArgs),
case erl_types:any_none_or_unit(InfList) of
true -> error;
false -> {ok, CDict}
end.
%%Inf = erl_types:t_inf(Contract1, Call),
%% Then unify with the constrained call type.
%% ?debug("Call: ~s\n", [erl_types:t_to_string(Call)]),
%% ?debug("Contract: ~s\n", [erl_types:t_to_string(Contract)]),
%% ?debug("Contract1: ~s\n", [erl_types:t_to_string(Contract1)]),
%% ?debug("Inf: ~s\n", [erl_types:t_to_string(Inf)]),
%% erl_types:t_assign_variables_to_subtype(Contract, Inf).
%% Checks the contracts for functions that are not implemented
-spec contracts_without_fun(dict(), [_], dialyzer_callgraph:callgraph()) -> [dial_warning()].
contracts_without_fun(Contracts, AllFuns0, Callgraph) ->
AllFuns1 = [{dialyzer_callgraph:lookup_name(Label, Callgraph), Arity}
|| {Label, Arity} <- AllFuns0],
AllFuns2 = [{M, F, A} || {{ok, {M, F, _}}, A} <- AllFuns1],
AllContractMFAs = dict:fetch_keys(Contracts),
ErrorContractMFAs = AllContractMFAs -- AllFuns2,
[warn_spec_missing_fun(MFA, Contracts) || MFA <- ErrorContractMFAs].
warn_spec_missing_fun({M, F, A} = MFA, Contracts) ->
{FileLine, _Contract} = dict:fetch(MFA, Contracts),
{?WARN_CONTRACT_SYNTAX, FileLine, {spec_missing_fun, [M, F, A]}}.
%% This treats the "when" constraints. It will be extended, we hope.
insert_constraints([{subtype, Type1, Type2}|Left], Dict) ->
case erl_types:t_is_var(Type1) of
true ->
Name = erl_types:t_var_name(Type1),
Dict1 = case dict:find(Name, Dict) of
error ->
dict:store(Name, Type2, Dict);
{ok, VarType} ->
dict:store(Name, erl_types:t_inf(VarType, Type2), Dict)
end,
insert_constraints(Left, Dict1);
false ->
%% A lot of things should change to add supertypes
throw({error, io_lib:format("First argument of is_subtype constraint "
"must be a type variable\n", [])})
end;
insert_constraints([], Dict) -> Dict.
-spec store_tmp_contract(mfa(), file_line(), [_], dict(), dict()) -> dict().
store_tmp_contract(MFA, FileLine, TypeSpec, SpecDict, RecordsDict) ->
%% io:format("contract from form: ~p\n", [TypeSpec]),
TmpContract = contract_from_form(TypeSpec, RecordsDict, FileLine),
%% io:format("contract: ~p\n", [Contract]),
dict:store(MFA, {FileLine, TmpContract}, SpecDict).
contract_from_form(Forms, RecDict, FileLine) ->
{CFuns, Forms1} = contract_from_form(Forms, RecDict, FileLine, [], []),
#tmp_contract{contract_funs = CFuns, forms = Forms1}.
contract_from_form([{type, _, 'fun', [_, _]} = Form | Left], RecDict,
FileLine, TypeAcc, FormAcc) ->
TypeFun =
fun(ExpTypes, AllRecords) ->
Type =
try
erl_types:t_from_form(Form, RecDict)
catch
throw:{error, Msg} ->
{File, Line} = FileLine,
NewMsg = io_lib:format("~s:~p: ~s", [filename:basename(File),
Line, Msg]),
throw({error, NewMsg})
end,
NewType = erl_types:t_solve_remote(Type, ExpTypes, AllRecords),
{NewType, []}
end,
NewTypeAcc = [TypeFun | TypeAcc],
NewFormAcc = [{Form, []} | FormAcc],
contract_from_form(Left, RecDict, FileLine, NewTypeAcc, NewFormAcc);
contract_from_form([{type, _L1, bounded_fun,
[{type, _L2, 'fun', [_, _]} = Form, Constr]}| Left],
RecDict, FileLine, TypeAcc, FormAcc) ->
TypeFun =
fun(ExpTypes, AllRecords) ->
Constr1 = [constraint_from_form(C, RecDict, ExpTypes, AllRecords)
|| C <- Constr],
VarDict = insert_constraints(Constr1, dict:new()),
Type = erl_types:t_from_form(Form, RecDict, VarDict),
NewType = erl_types:t_solve_remote(Type, ExpTypes, AllRecords),
{NewType, Constr1}
end,
NewTypeAcc = [TypeFun | TypeAcc],
NewFormAcc = [{Form, Constr} | FormAcc],
contract_from_form(Left, RecDict, FileLine, NewTypeAcc, NewFormAcc);
contract_from_form([], _RecDict, _FileLine, TypeAcc, FormAcc) ->
{lists:reverse(TypeAcc), lists:reverse(FormAcc)}.
constraint_from_form({type, _, constraint, [{atom, _, is_subtype},
[Type1, Type2]]}, RecDict,
ExpTypes, AllRecords) ->
T1 = erl_types:t_from_form(Type1, RecDict),
T2 = erl_types:t_from_form(Type2, RecDict),
T3 = erl_types:t_solve_remote(T1, ExpTypes, AllRecords),
T4 = erl_types:t_solve_remote(T2, ExpTypes, AllRecords),
{subtype, T3, T4};
constraint_from_form({type, _, constraint, [{atom,_,Name}, List]}, _RecDict,
_ExpTypes, _AllRecords) ->
N = length(List),
throw({error, io_lib:format("Unsupported type guard ~w/~w\n", [Name, N])}).
%% Gets the most general domain of a list of domains of all
%% the overloaded contracts
general_domain(List) ->
general_domain(List, erl_types:t_none()).
general_domain([{Sig, Constraints}|Left], AccSig) ->
Dict = insert_constraints(Constraints, dict:new()),
Sig1 = erl_types:t_subst(Sig, Dict),
general_domain(Left, erl_types:t_sup(AccSig, Sig1));
general_domain([], AccSig) ->
%% Get rid of all variables in the domain.
AccSig1 = erl_types:subst_all_vars_to_any(AccSig),
erl_types:t_fun_args(AccSig1).
-spec get_invalid_contract_warnings([module()], dialyzer_codeserver:codeserver(), dialyzer_plt:plt()) -> [dial_warning()].
get_invalid_contract_warnings(Modules, CodeServer, Plt) ->
get_invalid_contract_warnings_modules(Modules, CodeServer, Plt, []).
get_invalid_contract_warnings_modules([Mod|Mods], CodeServer, Plt, Acc) ->
Contracts1 = dialyzer_codeserver:lookup_mod_contracts(Mod, CodeServer),
Contracts2 = dict:to_list(Contracts1),
Records = dialyzer_codeserver:lookup_mod_records(Mod, CodeServer),
NewAcc = get_invalid_contract_warnings_funs(Contracts2, Plt, Records, Acc),
get_invalid_contract_warnings_modules(Mods, CodeServer, Plt, NewAcc);
get_invalid_contract_warnings_modules([], _CodeServer, _Plt, Acc) ->
Acc.
get_invalid_contract_warnings_funs([{MFA, {FileLine, Contract}}|Left],
Plt, RecDict, Acc) ->
case dialyzer_plt:lookup(Plt, MFA) of
none ->
%% This must be a contract for a non-available function. Just accept it.
get_invalid_contract_warnings_funs(Left, Plt, RecDict, Acc);
{value, {Ret, Args}} ->
Sig = erl_types:t_fun(Args, Ret),
NewAcc =
case check_contract(Contract, Sig) of
{error, invalid_contract} ->
[invalid_contract_warning(MFA, FileLine, Sig, RecDict)|Acc];
{error, {extra_range, ExtraRanges, STRange}} ->
Warn =
case t_from_forms_without_remote(Contract#contract.forms,
RecDict) of
{ok, NoRemoteType} ->
CRet = erl_types:t_fun_range(NoRemoteType),
erl_types:t_is_subtype(ExtraRanges, CRet);
unsupported ->
true
end,
case Warn of
true ->
[extra_range_warning(MFA, FileLine, ExtraRanges, STRange)|Acc];
false ->
Acc
end;
{error, Msg} ->
[{?WARN_CONTRACT_SYNTAX, FileLine, Msg}|Acc];
ok ->
{M, F, A} = MFA,
CSig0 = get_contract_signature(Contract),
CSig = erl_types:subst_all_vars_to_any(CSig0),
case erl_bif_types:is_known(M, F, A) of
true ->
%% This is strictly for contracts of functions also in
%% erl_bif_types
BifArgs = erl_bif_types:arg_types(M, F, A),
BifRet = erl_bif_types:type(M, F, A),
BifSig = erl_types:t_fun(BifArgs, BifRet),
case check_contract(Contract, BifSig) of
{error, _} ->
[invalid_contract_warning(MFA, FileLine, BifSig, RecDict)
|Acc];
ok ->
picky_contract_check(CSig, BifSig, MFA, FileLine,
Contract, RecDict, Acc)
end;
false ->
picky_contract_check(CSig, Sig, MFA, FileLine, Contract,
RecDict, Acc)
end
end,
get_invalid_contract_warnings_funs(Left, Plt, RecDict, NewAcc)
end;
get_invalid_contract_warnings_funs([], _Plt, _RecDict, Acc) ->
Acc.
invalid_contract_warning({M, F, A}, FileLine, SuccType, RecDict) ->
SuccTypeStr = dialyzer_utils:format_sig(SuccType, RecDict),
{?WARN_CONTRACT_TYPES, FileLine, {invalid_contract, [M, F, A, SuccTypeStr]}}.
extra_range_warning({M, F, A}, FileLine, ExtraRanges, STRange) ->
ERangesStr = erl_types:t_to_string(ExtraRanges),
STRangeStr = erl_types:t_to_string(STRange),
{?WARN_CONTRACT_SUPERTYPE, FileLine,
{extra_range, [M, F, A, ERangesStr, STRangeStr]}}.
picky_contract_check(CSig0, Sig0, MFA, FileLine, Contract, RecDict, Acc) ->
CSig = erl_types:t_abstract_records(CSig0, RecDict),
Sig = erl_types:t_abstract_records(Sig0, RecDict),
case erl_types:t_is_equal(CSig, Sig) of
true -> Acc;
false ->
case (erl_types:t_is_none(erl_types:t_fun_range(Sig)) andalso
erl_types:t_is_unit(erl_types:t_fun_range(CSig))) of
true -> Acc;
false ->
case extra_contract_warning(MFA, FileLine, Contract,
CSig, Sig, RecDict) of
no_warning -> Acc;
{warning, Warning} -> [Warning|Acc]
end
end
end.
extra_contract_warning({M, F, A}, FileLine, Contract, CSig, Sig, RecDict) ->
SigString = lists:flatten(dialyzer_utils:format_sig(Sig, RecDict)),
ContractString0 = lists:flatten(dialyzer_utils:format_sig(CSig, RecDict)),
%% The only difference is in record fields containing 'undefined' or not.
IsUndefRecordFieldsRelated = SigString =:= ContractString0,
{IsRemoteTypesRelated, SubtypeRelation} =
is_remote_types_related(Contract, CSig, Sig, RecDict),
case IsUndefRecordFieldsRelated orelse IsRemoteTypesRelated of
true ->
no_warning;
false ->
ContractString = contract_to_string(Contract),
{Tag, Msg} =
case SubtypeRelation of
contract_is_subtype ->
{?WARN_CONTRACT_SUBTYPE,
{contract_subtype, [M, F, A, ContractString, SigString]}};
contract_is_supertype ->
{?WARN_CONTRACT_SUPERTYPE,
{contract_supertype, [M, F, A, ContractString, SigString]}};
neither ->
{?WARN_CONTRACT_NOT_EQUAL,
{contract_diff, [M, F, A, ContractString, SigString]}}
end,
{warning, {Tag, FileLine, Msg}}
end.
is_remote_types_related(Contract, CSig, Sig, RecDict) ->
case erl_types:t_is_subtype(CSig, Sig) of
true ->
{false, contract_is_subtype};
false ->
case erl_types:t_is_subtype(Sig, CSig) of
true ->
case t_from_forms_without_remote(Contract#contract.forms, RecDict) of
{ok, NoRemoteTypeSig} ->
case blame_remote(CSig, NoRemoteTypeSig, Sig) of
true ->
{true, neither};
false ->
{false, contract_is_supertype}
end;
unsupported ->
{false, contract_is_supertype}
end;
false ->
{false, neither}
end
end.
t_from_forms_without_remote([{FType, []}], RecDict) ->
Type0 = erl_types:t_from_form(FType, RecDict),
Map =
fun(Type) ->
case erl_types:t_is_remote(Type) of
true -> erl_types:t_none();
false -> Type
end
end,
{ok, erl_types:t_map(Map, Type0)};
t_from_forms_without_remote([{_FType, _Constrs}], _RecDict) ->
%% 'When' constraints
unsupported;
t_from_forms_without_remote(_Forms, _RecDict) ->
%% Lots of forms
unsupported.
blame_remote(ContractSig, NoRemoteContractSig, Sig) ->
CArgs = erl_types:t_fun_args(ContractSig),
CRange = erl_types:t_fun_range(ContractSig),
NRArgs = erl_types:t_fun_args(NoRemoteContractSig),
NRRange = erl_types:t_fun_range(NoRemoteContractSig),
SArgs = erl_types:t_fun_args(Sig),
SRange = erl_types:t_fun_range(Sig),
blame_remote_list([CRange|CArgs], [NRRange|NRArgs], [SRange|SArgs]).
blame_remote_list([], [], []) ->
true;
blame_remote_list([CArg|CArgs], [NRArg|NRArgs], [SArg|SArgs]) ->
case erl_types:t_is_equal(CArg, NRArg) of
true ->
case not erl_types:t_is_equal(CArg, SArg) of
true -> false;
false -> blame_remote_list(CArgs, NRArgs, SArgs)
end;
false ->
case erl_types:t_is_subtype(SArg, NRArg)
andalso not erl_types:t_is_subtype(NRArg, SArg) of
true -> false;
false -> blame_remote_list(CArgs, NRArgs, SArgs)
end
end.
