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-rw-r--r--lib/stdlib/src/erl_lint.erl166
-rw-r--r--lib/stdlib/test/erl_lint_SUITE.erl109
2 files changed, 199 insertions, 76 deletions
diff --git a/lib/stdlib/src/erl_lint.erl b/lib/stdlib/src/erl_lint.erl
index f34c3b5c7b..6619ed5221 100644
--- a/lib/stdlib/src/erl_lint.erl
+++ b/lib/stdlib/src/erl_lint.erl
@@ -2121,8 +2121,8 @@ expr({'receive',Line,Cs,To,ToEs}, Vt, St0) ->
{Cvt,St3} = icrt_clauses(Cs, Vt, St2),
%% Csvts = [vtnew(Tevt, Vt)|Cvt], %This is just NEW variables!
Csvts = [Tevt|Cvt],
- {Rvt,St4} = icrt_export(Csvts, Vt, {'receive',Line}, St3),
- {vtmerge([Tvt,Tevt,Rvt]),St4};
+ Rvt = icrt_export(Csvts, Vt, {'receive',Line}),
+ {vtmerge([Tvt,Tevt,Rvt]),St3};
expr({'fun',Line,Body}, Vt, St) ->
%%No one can think funs export!
case Body of
@@ -2233,21 +2233,20 @@ expr({'try',Line,Es,Scs,Ccs,As}, Vt, St0) ->
%% passes cannot handle exports in combination with 'after'.
{Evt0,St1} = exprs(Es, Vt, St0),
TryLine = {'try',Line},
- Uvt = vtunsafe(vtnames(vtnew(Evt0, Vt)), TryLine, []),
- Evt1 = vtupdate(Uvt, vtsubtract(Evt0, Uvt)),
+ Uvt = vtunsafe(TryLine, Evt0, Vt),
+ Evt1 = vtupdate(Uvt, Evt0),
{Sccs,St2} = icrt_clauses(Scs++Ccs, TryLine, vtupdate(Evt1, Vt), St1),
Rvt0 = Sccs,
- Rvt1 = vtupdate(vtunsafe(vtnames(vtnew(Rvt0, Vt)), TryLine, []), Rvt0),
+ Rvt1 = vtupdate(vtunsafe(TryLine, Rvt0, Vt), Rvt0),
Evt2 = vtmerge(Evt1, Rvt1),
{Avt0,St} = exprs(As, vtupdate(Evt2, Vt), St2),
- Avt1 = vtupdate(vtunsafe(vtnames(vtnew(Avt0, Vt)), TryLine, []), Avt0),
+ Avt1 = vtupdate(vtunsafe(TryLine, Avt0, Vt), Avt0),
Avt = vtmerge(Evt2, Avt1),
{Avt,St};
expr({'catch',Line,E}, Vt, St0) ->
%% No new variables added, flag new variables as unsafe.
- {Evt,St1} = expr(E, Vt, St0),
- Uvt = vtunsafe(vtnames(vtnew(Evt, Vt)), {'catch',Line}, []),
- {vtupdate(Uvt,vtupdate(Evt, Vt)),St1};
+ {Evt,St} = expr(E, Vt, St0),
+ {vtupdate(vtunsafe({'catch',Line}, Evt, Vt), Evt),St};
expr({match,_Line,P,E}, Vt, St0) ->
{Evt,St1} = expr(E, Vt, St0),
{Pvt,Bvt,St2} = pattern(P, vtupdate(Evt, Vt), St1),
@@ -2260,9 +2259,8 @@ expr({op,Line,Op,L,R}, Vt, St0) when Op =:= 'orelse'; Op =:= 'andalso' ->
{Evt1,St1} = expr(L, Vt, St0),
Vt1 = vtupdate(Evt1, Vt),
{Evt2,St2} = expr(R, Vt1, St1),
- Vt2 = vtmerge(Evt2, Vt1),
- {Vt3,St3} = icrt_export([Vt1,Vt2], Vt1, {Op,Line}, St2),
- {vtmerge(Evt1, Vt3),St3};
+ Evt3 = vtupdate(vtunsafe({Op,Line}, Evt2, Vt1), Evt2),
+ {vtmerge(Evt1, Evt3),St2};
expr({op,_Line,_Op,L,R}, Vt, St) ->
expr_list([L,R], Vt, St); %They see the same variables
%% The following are not allowed to occur anywhere!
@@ -3024,11 +3022,12 @@ check_local_opaque_types(St) ->
dict:fold(FoldFun, St, Ts).
%% icrt_clauses(Clauses, In, ImportVarTable, State) ->
-%% {NewVts,State}.
+%% {UpdVt,State}.
icrt_clauses(Cs, In, Vt, St0) ->
{Csvt,St1} = icrt_clauses(Cs, Vt, St0),
- icrt_export(Csvt, Vt, In, St1).
+ UpdVt = icrt_export(Csvt, Vt, In),
+ {UpdVt,St1}.
%% icrt_clauses(Clauses, ImportVarTable, State) ->
%% {NewVts,State}.
@@ -3038,26 +3037,73 @@ icrt_clauses(Cs, Vt, St) ->
icrt_clause({clause,_Line,H,G,B}, Vt0, St0) ->
{Hvt,Binvt,St1} = head(H, Vt0, St0),
- Vt1 = vtupdate(Hvt, vtupdate(Binvt, Vt0)),
- {Gvt,St2} = guard(G, Vt1, St1),
+ Vt1 = vtupdate(Hvt, Binvt),
+ {Gvt,St2} = guard(G, vtupdate(Vt1, Vt0), St1),
Vt2 = vtupdate(Gvt, Vt1),
- {Bvt,St3} = exprs(B, Vt2, St2),
+ {Bvt,St3} = exprs(B, vtupdate(Vt2, Vt0), St2),
{vtupdate(Bvt, Vt2),St3}.
-icrt_export(Csvt, Vt, In, St) ->
- Vt1 = vtmerge(Csvt),
- All = ordsets:subtract(vintersection(Csvt), vtnames(Vt)),
- Some = ordsets:subtract(vtnames(Vt1), vtnames(Vt)),
- Xvt = vtexport(All, In, []),
- Evt = vtunsafe(ordsets:subtract(Some, All), In, Xvt),
- Unused = vtmerge([unused_vars(Vt0, Vt, St) || Vt0 <- Csvt]),
- %% Exported and unsafe variables may be unused:
- Uvt = vtmerge(Evt, Unused),
- %% Make exported and unsafe unused variables unused in subsequent code:
- Vt2 = vtmerge(Uvt, vtsubtract(Vt1, Uvt)),
- %% Forget about old variables which were not used:
- Vt3 = vtmerge(vtnew(Vt2, Vt), vt_no_unused(vtold(Vt2, Vt))),
- {Vt3,St}.
+icrt_export(Vts, Vt, {Tag,Attrs}) ->
+ {_File,Loc} = loc(Attrs),
+ icrt_export(lists:merge(Vts), Vt, {Tag,Loc}, length(Vts), []).
+
+icrt_export([{V,{{export,_},_,_}}|Vs0], [{V,{{export,_}=S0,_,Ls}}|Vt],
+ In, I, Acc) ->
+ %% V was an exported variable and has been used in an expression in at least
+ %% one clause. Its state needs to be merged from all clauses to silence any
+ %% exported var warning already emitted.
+ {VVs,Vs} = lists:partition(fun ({K,_}) -> K =:= V end, Vs0),
+ S = foldl(fun ({_,{S1,_,_}}, AccS) -> merge_state(AccS, S1) end, S0, VVs),
+ icrt_export(Vs, Vt, In, I, [{V,{S,used,Ls}}|Acc]);
+icrt_export([{V,_}|Vs0], [{V,{_,_,Ls}}|Vt], In, I, Acc) ->
+ %% V was either unsafe or bound and has now been reused. It may also have
+ %% been an export but as it was not matched by the previous clause, it means
+ %% it has been changed to 'bound' in at least one clause because it was used
+ %% in a pattern.
+ Vs = lists:dropwhile(fun ({K,_}) -> K =:= V end, Vs0),
+ icrt_export(Vs, Vt, In, I, [{V,{bound,used,Ls}}|Acc]);
+icrt_export([{V1,_}|_]=Vs, [{V2,_}|Vt], In, I, Acc) when V1 > V2 ->
+ %% V2 was already in scope and has not been reused in any clause.
+ icrt_export(Vs, Vt, In, I, Acc);
+icrt_export([{V,_}|_]=Vs0, Vt, In, I, Acc) ->
+ %% V is a new variable.
+ {VVs,Vs} = lists:partition(fun ({K,_}) -> K =:= V end, Vs0),
+ F = fun ({_,{S,U,Ls}}, {AccI,AccS0,AccLs0}) ->
+ AccS = case {S,AccS0} of
+ {{unsafe,_},{unsafe,_}} ->
+ %% V was found unsafe in a previous clause, mark
+ %% it as unsafe for the whole parent expression.
+ {unsafe,In};
+ {{unsafe,_},_} ->
+ %% V was unsafe in a clause, keep that state and
+ %% generalize it to the whole expression if it
+ %% is found unsafe in another one.
+ S;
+ _ ->
+ %% V is either bound or exported, keep original
+ %% state.
+ AccS0
+ end,
+ AccLs = case U of
+ used -> AccLs0;
+ unused -> merge_lines(AccLs0, Ls)
+ end,
+ {AccI + 1,AccS,AccLs}
+ end,
+ %% Initial state is exported from the current expression.
+ {Count,S1,Ls} = foldl(F, {0,{export,In},[]}, VVs),
+ S = case Count of
+ I ->
+ %% V was found in all clauses, keep computed state.
+ S1;
+ _ ->
+ %% V was not bound in some clauses, mark as unsafe.
+ {unsafe,In}
+ end,
+ U = case Ls of [] -> used; _ -> unused end,
+ icrt_export(Vs, Vt, In, I, [{V,{S,U,Ls}}|Acc]);
+icrt_export([], _, _, _, Acc) ->
+ reverse(Acc).
handle_comprehension(E, Qs, Vt0, St0) ->
{Vt1, Uvt, St1} = lc_quals(Qs, Vt0, St0),
@@ -3155,7 +3201,8 @@ fun_clauses(Cs, Vt, St) ->
{Cvt,St1} = fun_clause(C, Vt, St0),
{vtmerge(Cvt, Bvt0),St1}
end, {[],St#lint{recdef_top = false}}, Cs),
- {vt_no_unused(vtold(Bvt, Vt)),St2#lint{recdef_top = OldRecDef}}.
+ Uvt = vt_no_unsafe(vt_no_unused(vtold(Bvt, Vt))),
+ {Uvt,St2#lint{recdef_top = OldRecDef}}.
fun_clause({clause,_Line,H,G,B}, Vt0, St0) ->
{Hvt,Binvt,St1} = head(H, Vt0, [], St0), % No imported pattern variables
@@ -3269,19 +3316,24 @@ pat_binsize_var(V, Line, Vt, Bvt, St) ->
%% exported vars are probably safe, warn only if warn_export_vars is
%% set.
-expr_var(V, Line, Vt, St0) ->
+expr_var(V, Line, Vt, St) ->
case orddict:find(V, Vt) of
{ok,{bound,_Usage,Ls}} ->
- {[{V,{bound,used,Ls}}],St0};
+ {[{V,{bound,used,Ls}}],St};
{ok,{{unsafe,In},_Usage,Ls}} ->
{[{V,{bound,used,Ls}}],
- add_error(Line, {unsafe_var,V,In}, St0)};
+ add_error(Line, {unsafe_var,V,In}, St)};
{ok,{{export,From},_Usage,Ls}} ->
- {[{V,{bound,used,Ls}}],
- exported_var(Line, V, From, St0)};
+ case is_warn_enabled(export_vars, St) of
+ true ->
+ {[{V,{bound,used,Ls}}],
+ add_warning(Line, {exported_var,V,From}, St)};
+ false ->
+ {[{V,{{export,From},used,Ls}}],St}
+ end;
error ->
{[{V,{bound,used,[Line]}}],
- add_error(Line, {unbound_var,V}, St0)}
+ add_error(Line, {unbound_var,V}, St)}
end.
exported_var(Line, V, From, St) ->
@@ -3345,17 +3397,12 @@ vtupdate(Uvt, Vt0) ->
{S, merge_used(U1, U2), merge_lines(L1, L2)}
end, Uvt, Vt0).
-%% vtexport([Variable], From, VarTable) -> VarTable.
-%% vtunsafe([Variable], From, VarTable) -> VarTable.
-%% Add the variables to VarTable either as exported from From or as unsafe.
-
-vtexport(Vs, {InTag,FileLine}, Vt0) ->
- {_File,Line} = loc(FileLine),
- vtupdate([{V,{{export,{InTag,Line}},unused,[]}} || V <- Vs], Vt0).
+%% vtunsafe(From, UpdVarTable, VarTable) -> UnsafeVarTable.
+%% Return all new variables in UpdVarTable as unsafe.
-vtunsafe(Vs, {InTag,FileLine}, Vt0) ->
+vtunsafe({Tag,FileLine}, Uvt, Vt) ->
{_File,Line} = loc(FileLine),
- vtupdate([{V,{{unsafe,{InTag,Line}},unused,[]}} || V <- Vs], Vt0).
+ [{V,{{unsafe,{Tag,Line}},U,Ls}} || {V,{_,U,Ls}} <- vtnew(Uvt, Vt)].
%% vtmerge(VarTable, VarTable) -> VarTable.
%% Merge two variables tables generating a new vartable. Give priority to
@@ -3408,8 +3455,6 @@ vtsubtract(New, Old) ->
vtold(New, Old) ->
orddict:filter(fun (V, _How) -> orddict:is_key(V, Old) end, New).
-vtnames(Vt) -> [ V || {V,_How} <- Vt ].
-
vt_no_unsafe(Vt) -> [V || {_,{S,_U,_L}}=V <- Vt,
case S of
{unsafe,_} -> false;
@@ -3418,29 +3463,6 @@ vt_no_unsafe(Vt) -> [V || {_,{S,_U,_L}}=V <- Vt,
vt_no_unused(Vt) -> [V || {_,{_,U,_L}}=V <- Vt, U =/= unused].
-%% vunion(VarTable1, VarTable2) -> [VarName].
-%% vunion([VarTable]) -> [VarName].
-%% vintersection(VarTable1, VarTable2) -> [VarName].
-%% vintersection([VarTable]) -> [VarName].
-%% Union/intersection of names of vars in VarTable.
-
--ifdef(NOTUSED).
-vunion(Vs1, Vs2) -> ordsets:union(vtnames(Vs1), vtnames(Vs2)).
-
-vunion(Vss) -> foldl(fun (Vs, Uvs) ->
- ordsets:union(vtnames(Vs), Uvs)
- end, [], Vss).
-
-vintersection(Vs1, Vs2) -> ordsets:intersection(vtnames(Vs1), vtnames(Vs2)).
--endif.
-
-vintersection([Vs]) ->
- vtnames(Vs); %Boundary conditions!!!
-vintersection([Vs|Vss]) ->
- ordsets:intersection(vtnames(Vs), vintersection(Vss));
-vintersection([]) ->
- [].
-
%% copy_expr(Expr, Line) -> Expr.
%% Make a copy of Expr converting all line numbers to Line.
diff --git a/lib/stdlib/test/erl_lint_SUITE.erl b/lib/stdlib/test/erl_lint_SUITE.erl
index ca91d94213..27f95bd3fa 100644
--- a/lib/stdlib/test/erl_lint_SUITE.erl
+++ b/lib/stdlib/test/erl_lint_SUITE.erl
@@ -42,6 +42,7 @@
unused_vars_warn_rec/1,
unused_vars_warn_fun/1,
unused_vars_OTP_4858/1,
+ unused_unsafe_vars_warn/1,
export_vars_warn/1,
shadow_vars/1,
unused_import/1,
@@ -98,7 +99,7 @@ groups() ->
[{unused_vars_warn, [],
[unused_vars_warn_basic, unused_vars_warn_lc,
unused_vars_warn_rec, unused_vars_warn_fun,
- unused_vars_OTP_4858]},
+ unused_vars_OTP_4858, unused_unsafe_vars_warn]},
{on_load, [], [on_load_successful, on_load_failing]}].
init_per_suite(Config) ->
@@ -730,6 +731,48 @@ unused_vars_OTP_4858(Config) when is_list(Config) ->
?line [] = run(Config, Ts),
ok.
+unused_unsafe_vars_warn(Config) when is_list(Config) ->
+ Ts = [{unused_unsafe1,
+ <<"t1() ->
+ UnusedVar1 = unused1,
+ try
+ UnusedVar2 = unused2
+ catch
+ _:_ ->
+ ok
+ end,
+ ok.
+ ">>,
+ [warn_unused_vars],
+ {warnings,[{2,erl_lint,{unused_var,'UnusedVar1'}},
+ {4,erl_lint,{unused_var,'UnusedVar2'}}]}},
+ {unused_unsafe2,
+ <<"t2() ->
+ try
+ X = 1
+ catch
+ _:_ -> ok
+ end.
+ ">>,
+ [warn_unused_vars],
+ {warnings,[{3,erl_lint,{unused_var,'X'}}]}},
+ {unused_unsafe2,
+ <<"t3(X, Y) ->
+ X andalso Y.
+ ">>,
+ [warn_unused_vars],
+ []},
+ {unused_unsafe4,
+ <<"t4() ->
+ _ = (catch X = X = 1),
+ _ = case ok of _ -> fun() -> ok end end,
+ fun (X) -> X end.
+ ">>,
+ [warn_unused_vars],
+ []}],
+ run(Config, Ts),
+ ok.
+
export_vars_warn(doc) ->
"Warnings for exported variables";
export_vars_warn(suite) -> [];
@@ -808,7 +851,19 @@ export_vars_warn(Config) when is_list(Config) ->
[],
{error,[{9,erl_lint,{unbound_var,'B'}}],
[{9,erl_lint,{exported_var,'Y',{'receive',2}}},
- {10,erl_lint,{shadowed_var,'B',generate}}]}}
+ {10,erl_lint,{shadowed_var,'B',generate}}]}},
+
+ {exp4,
+ <<"t(X) ->
+ if true -> Z = X end,
+ case X of
+ 1 -> Z;
+ 2 -> X
+ end,
+ Z = X.
+ ">>,
+ [],
+ {warnings,[{7,erl_lint,{exported_var,'Z',{'if',2}}}]}}
],
?line [] = run(Config, Ts),
ok.
@@ -832,8 +887,15 @@ shadow_vars(Config) when is_list(Config) ->
">>,
[nowarn_shadow_vars],
{error,[{9,erl_lint,{unbound_var,'B'}}],
- [{9,erl_lint,{exported_var,'Y',{'receive',2}}}]}}],
-
+ [{9,erl_lint,{exported_var,'Y',{'receive',2}}}]}},
+ {shadow2,
+ <<"t() ->
+ _ = (catch MS = MS = 1), % MS used unsafe
+ _ = case ok of _ -> fun() -> ok end end,
+ fun (MS) -> MS end. % MS not shadowed here
+ ">>,
+ [],
+ []}],
?line [] = run(Config, Ts),
ok.
@@ -958,6 +1020,45 @@ unsafe_vars(Config) when is_list(Config) ->
[warn_unused_vars],
{errors,[{3,erl_lint,{unsafe_var,'X',{'if',2}}},
{4,erl_lint,{unsafe_var,'X',{'if',2}}}],
+ []}},
+ {unsafe8,
+ <<"t8(X) ->
+ case X of _ -> catch _Y = 1 end,
+ _Y."
+ >>,
+ [],
+ {errors,[{3,erl_lint,{unsafe_var,'_Y',{'catch',2}}}],
+ []}},
+ {unsafe9,
+ <<"t9(X) ->
+ case X of
+ 1 ->
+ catch A = 1, % unsafe only here
+ B = 1,
+ C = 1,
+ D = 1;
+ 2 ->
+ A = 2,
+ % B not bound here
+ C = 2,
+ catch D = 2; % unsafe in two clauses
+ 3 ->
+ A = 3,
+ B = 3,
+ C = 3,
+ catch D = 3; % unsafe in two clauses
+ 4 ->
+ A = 4,
+ B = 4,
+ C = 4,
+ D = 4
+ end,
+ {A,B,C,D}."
+ >>,
+ [],
+ {errors,[{24,erl_lint,{unsafe_var,'A',{'catch',4}}},
+ {24,erl_lint,{unsafe_var,'B',{'case',2}}},
+ {24,erl_lint,{unsafe_var,'D',{'case',2}}}],
[]}}
],
?line [] = run(Config, Ts),
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-28 08:45:12 +0000