From 91048957f0681dba853f5720d3618aa1c5d0255e Mon Sep 17 00:00:00 2001 From: Hans Bolinder Date: Tue, 29 Nov 2016 09:37:21 +0100 Subject: stdilb: Check for bad type constraints in function types The parser recognizes the 'is_subtype(V, T)' syntax for constraints, and of course the new 'V :: T' syntax, but other variants result in an error message. Up to now, the parser and linter have let badly formed constraints through, and relied upon Dialyzer to emit warnings. is_subtype/2 cannot easily be taken out from the parser. Not only would we need find a way to emit a (linter) warning, but there also needs to be an option for suppressing the linter warning as compilation with +warnings_as_errors has to work. (Notice that the abstract format representation for 'V :: T' is the same as for 'is_subtype(V, T)'.) This correction was triggered by an email from Robert, and Kostis created pull request 1214 to provide a fix. However, Kostis' fix disallowed is_subtype() altogether, which breaks backward compatibility. As of Erlang/OTP 19.0 (ticket OTP-11879), the 'is_subtype(V, T)' is no longer documented. --- erts/doc/src/absform.xml | 2 +- lib/stdlib/src/erl_parse.yrl | 36 +++++++++++++++----------- lib/stdlib/test/erl_lint_SUITE.erl | 53 ++++++++++++++++++++++++++++++++++++-- lib/stdlib/test/erl_pp_SUITE.erl | 13 +++++----- 4 files changed, 80 insertions(+), 24 deletions(-) diff --git a/erts/doc/src/absform.xml b/erts/doc/src/absform.xml index ab00d47425..fe8e3b30e7 100644 --- a/erts/doc/src/absform.xml +++ b/erts/doc/src/absform.xml @@ -886,7 +886,7 @@ Rep(Fc) = [Rep(C_1), ..., Rep(C_k)].

- If C is a constraint is_subtype(V, T) or V :: T, + If C is a constraint V :: T, where V is a type variable and T is a type, then Rep(C) = {type,LINE,constraint,[{atom,LINE,is_subtype},[Rep(V),Rep(T)]]}. diff --git a/lib/stdlib/src/erl_parse.yrl b/lib/stdlib/src/erl_parse.yrl index 9cd95705af..a0bc21fbc5 100644 --- a/lib/stdlib/src/erl_parse.yrl +++ b/lib/stdlib/src/erl_parse.yrl @@ -33,7 +33,6 @@ list tail list_comprehension lc_expr lc_exprs binary_comprehension tuple -%struct record_expr record_tuple record_field record_fields map_expr map_tuple map_field map_field_assoc map_field_exact map_fields map_key if_expr if_clause if_clauses case_expr cr_clause cr_clauses receive_expr @@ -108,9 +107,8 @@ type_sig -> fun_type 'when' type_guards : {type, ?anno('$1'), bounded_fun, type_guards -> type_guard : ['$1']. type_guards -> type_guard ',' type_guards : ['$1'|'$3']. -type_guard -> atom '(' top_types ')' : {type, ?anno('$1'), constraint, - ['$1', '$3']}. -type_guard -> var '::' top_type : build_def('$1', '$3'). +type_guard -> atom '(' top_types ')' : build_compat_constraint('$1', '$3'). +type_guard -> var '::' top_type : build_constraint('$1', '$3'). top_types -> top_type : ['$1']. top_types -> top_type ',' top_types : ['$1'|'$3']. @@ -268,7 +266,6 @@ expr_max -> binary : '$1'. expr_max -> list_comprehension : '$1'. expr_max -> binary_comprehension : '$1'. expr_max -> tuple : '$1'. -%%expr_max -> struct : '$1'. expr_max -> '(' expr ')' : '$2'. expr_max -> 'begin' exprs 'end' : {block,?anno('$1'),'$2'}. expr_max -> if_expr : '$1'. @@ -327,10 +324,6 @@ lc_expr -> binary '<=' expr : {b_generate,?anno('$2'),'$1','$3'}. tuple -> '{' '}' : {tuple,?anno('$1'),[]}. tuple -> '{' exprs '}' : {tuple,?anno('$1'),'$2'}. - -%%struct -> atom tuple : -%% {struct,?anno('$1'),element(3, '$1'),element(3, '$2')}. - map_expr -> '#' map_tuple : {map, ?anno('$1'),'$2'}. map_expr -> expr_max '#' map_tuple : @@ -1056,13 +1049,13 @@ build_typed_attribute({atom,Aa,Attr},_) -> end. build_type_spec({Kind,Aa}, {SpecFun, TypeSpecs}) - when (Kind =:= spec) or (Kind =:= callback) -> + when Kind =:= spec ; Kind =:= callback -> NewSpecFun = case SpecFun of {atom, _, Fun} -> {Fun, find_arity_from_specs(TypeSpecs)}; - {{atom,_, Mod}, {atom,_, Fun}} -> - {Mod,Fun,find_arity_from_specs(TypeSpecs)} + {{atom, _, Mod}, {atom, _, Fun}} -> + {Mod, Fun, find_arity_from_specs(TypeSpecs)} end, {attribute,Aa,Kind,{NewSpecFun, TypeSpecs}}. @@ -1076,11 +1069,24 @@ find_arity_from_specs([Spec|_]) -> {type, _, 'fun', [{type, _, product, Args},_]} = Fun, length(Args). -build_def({var, A, '_'}, _Types) -> +%% The 'is_subtype(V, T)' syntax is not supported as of Erlang/OTP +%% 19.0, but is kept for backward compatibility. +build_compat_constraint({atom, _, is_subtype}, [{var, _, _}=LHS, Type]) -> + build_constraint(LHS, Type); +build_compat_constraint({atom, _, is_subtype}, [LHS, _Type]) -> + ret_err(?anno(LHS), "bad type variable"); +build_compat_constraint({atom, A, Atom}, _Types) -> + ret_err(A, io_lib:format("unsupported constraint ~w", [Atom])). + +build_constraint({atom, _, is_subtype}, [{var, _, _}=LHS, Type]) -> + build_constraint(LHS, Type); +build_constraint({atom, A, Atom}, _Foo) -> + ret_err(A, io_lib:format("unsupported constraint ~w", [Atom])); +build_constraint({var, A, '_'}, _Types) -> ret_err(A, "bad type variable"); -build_def(LHS, Types) -> +build_constraint(LHS, Type) -> IsSubType = {atom, ?anno(LHS), is_subtype}, - {type, ?anno(LHS), constraint, [IsSubType, [LHS, Types]]}. + {type, ?anno(LHS), constraint, [IsSubType, [LHS, Type]]}. lift_unions(T1, {type, _Aa, union, List}) -> {type, ?anno(T1), union, [T1|List]}; diff --git a/lib/stdlib/test/erl_lint_SUITE.erl b/lib/stdlib/test/erl_lint_SUITE.erl index 4ee3950882..1dc7c58337 100644 --- a/lib/stdlib/test/erl_lint_SUITE.erl +++ b/lib/stdlib/test/erl_lint_SUITE.erl @@ -64,7 +64,7 @@ predef/1, maps/1,maps_type/1,maps_parallel_match/1, otp_11851/1,otp_11879/1,otp_13230/1, - record_errors/1]). + record_errors/1, otp_xxxxx/1]). suite() -> [{ct_hooks,[ts_install_cth]}, @@ -84,7 +84,7 @@ all() -> too_many_arguments, basic_errors, bin_syntax_errors, predef, maps, maps_type, maps_parallel_match, otp_11851, otp_11879, otp_13230, - record_errors]. + record_errors, otp_xxxxx]. groups() -> [{unused_vars_warn, [], @@ -3869,6 +3869,55 @@ record_errors(Config) when is_list(Config) -> {3,erl_lint,{redefine_field,r,a}}],[]}}], run(Config, Ts). +otp_xxxxx(Config) -> + Ts = [{constraint1, + <<"-export([t/1]). + -spec t(X) -> X when is_subtype(integer()). + t(a) -> foo:bar(). + ">>, + [], + {errors, + [{2,erl_parse,"unsupported constraint " ++ ["is_subtype"]}], + []}}, + {constraint2, + <<"-export([t/1]). + -spec t(X) -> X when bad_atom(X, integer()). + t(a) -> foo:bar(). + ">>, + [], + {errors, + [{2,erl_parse,"unsupported constraint " ++ ["bad_atom"]}], + []}}, + {constraint3, + <<"-export([t/1]). + -spec t(X) -> X when is_subtype(bad_variable, integer()). + t(a) -> foo:bar(). + ">>, + [], + {errors,[{2,erl_parse,"bad type variable"}],[]}}, + {constraint4, + <<"-export([t/1]). + -spec t(X) -> X when is_subtype(atom(), integer()). + t(a) -> foo:bar(). + ">>, + [], + {errors,[{2,erl_parse,"bad type variable"}],[]}}, + {constraint5, + <<"-export([t/1]). + -spec t(X) -> X when is_subtype(X, integer()). + t(a) -> foo:bar(). + ">>, + [], + []}, + {constraint6, + <<"-export([t/1]). + -spec t(X) -> X when X :: integer(). + t(a) -> foo:bar(). + ">>, + [], + []}], + run(Config, Ts). + run(Config, Tests) -> F = fun({N,P,Ws,E}, BadL) -> case catch run_test(Config, P, Ws) of diff --git a/lib/stdlib/test/erl_pp_SUITE.erl b/lib/stdlib/test/erl_pp_SUITE.erl index 13c5662741..31ea3210a8 100644 --- a/lib/stdlib/test/erl_pp_SUITE.erl +++ b/lib/stdlib/test/erl_pp_SUITE.erl @@ -825,12 +825,13 @@ type_examples() -> %% is_subtype(V, T) syntax, we need a few examples of the syntax. {ex31,<<"-spec t1(FooBar :: t99()) -> t99();" "(t2()) -> t2();" - "('\\'t::4'()) -> '\\'t::4'() when is_subtype('\\'t::4'(), t24);" - "(t23()) -> t23() when is_subtype(t23(), atom())," - " is_subtype(t23(), t14());" - "(t24()) -> t24() when is_subtype(t24(), atom())," - " is_subtype(t24(), t14())," - " is_subtype(t24(), '\\'t::4'()).">>}, + "('\\'t::4'()) -> {'\\'t::4'(), B}" + " when is_subtype(B, '\\'t::4'());" + "(t23()) -> C when is_subtype(C, atom())," + " is_subtype(C, t14());" + "(t24()) -> D when is_subtype(D, atom())," + " is_subtype(D, t14())," + " is_subtype(D, '\\'t::4'()).">>}, {ex32,<<"-spec mod:t2() -> any(). ">>}, {ex33,<<"-opaque attributes_data() :: " "[{'column', column()} | {'line', info_line()} |" -- cgit v1.2.3