File 1207-stdlib-Fix-linting-of-map-key-variables.patch of Package erlang
From 8f31e06634f06152a85fa6579879907bdc4b6a54 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn-Egil=20Dahlberg?= <egil@erlang.org>
Date: Sat, 30 Apr 2016 15:07:48 +0200
Subject: [PATCH 1/4] stdlib: Fix linting of map key variables
Map keys cannot be bound and then used in parallel matching.
Example:
#{ K := V } = #{ k := K } = M.
This is illegal if 'K' is not already bound.
---
lib/stdlib/src/erl_lint.erl | 97 +++++++++++++++++++++++++++++----------------
1 file changed, 63 insertions(+), 34 deletions(-)
diff --git a/lib/stdlib/src/erl_lint.erl b/lib/stdlib/src/erl_lint.erl
index b14102a..2508f96 100644
--- a/lib/stdlib/src/erl_lint.erl
+++ b/lib/stdlib/src/erl_lint.erl
@@ -1502,7 +1502,7 @@ pattern({op,_Line,'++',{string,_Li,_S},R}, Vt, Old, Bvt, St) ->
pattern({match,_Line,Pat1,Pat2}, Vt, Old, Bvt, St0) ->
{Lvt,Bvt1,St1} = pattern(Pat1, Vt, Old, Bvt, St0),
{Rvt,Bvt2,St2} = pattern(Pat2, Vt, Old, Bvt, St1),
- St3 = reject_bin_alias(Pat1, Pat2, St2),
+ St3 = reject_invalid_alias(Pat1, Pat2, Vt, St2),
{vtmerge_pat(Lvt, Rvt),vtmerge_pat(Bvt1,Bvt2),St3};
%% Catch legal constant expressions, including unary +,-.
pattern(Pat, _Vt, _Old, _Bvt, St) ->
@@ -1517,56 +1517,77 @@ pattern_list(Ps, Vt, Old, Bvt0, St) ->
{vtmerge_pat(Pvt, Psvt),vtmerge_pat(Bvt,Bvt1),St1}
end, {[],[],St}, Ps).
-%% reject_bin_alias(Pat, Expr, St) -> St'
+
+
+%% reject_invalid_alias(Pat, Expr, Vt, St) -> St'
%% Reject aliases for binary patterns at the top level.
+%% Reject aliases for maps patterns at the top level.
+%% The variables table (Vt) are for maps checkking.
+
+reject_invalid_alias_expr({bin,_,_}=P, {match,_,P0,E}, Vt, St0) ->
+ St = reject_invalid_alias(P, P0, Vt, St0),
+ reject_invalid_alias_expr(P, E, Vt, St);
+reject_invalid_alias_expr({map,_,_}=P, {match,_,P0,E}, Vt, St0) ->
+ St = reject_invalid_alias(P, P0, Vt, St0),
+ reject_invalid_alias_expr(P, E, Vt, St);
+reject_invalid_alias_expr({match,_,_,_}=P, {match,_,P0,E}, Vt, St0) ->
+ St = reject_invalid_alias(P, P0, Vt, St0),
+ reject_invalid_alias_expr(P, E, Vt, St);
+reject_invalid_alias_expr(_, _, _, St) -> St.
-reject_bin_alias_expr({bin,_,_}=P, {match,_,P0,E}, St0) ->
- St = reject_bin_alias(P, P0, St0),
- reject_bin_alias_expr(P, E, St);
-reject_bin_alias_expr({match,_,_,_}=P, {match,_,P0,E}, St0) ->
- St = reject_bin_alias(P, P0, St0),
- reject_bin_alias_expr(P, E, St);
-reject_bin_alias_expr(_, _, St) -> St.
-%% reject_bin_alias(Pat1, Pat2, St) -> St'
+%% reject_invalid_alias(Pat1, Pat2, St) -> St'
%% Aliases of binary patterns, such as <<A:8>> = <<B:4,C:4>> or even
%% <<A:8>> = <<A:8>>, are not allowed. Traverse the patterns in parallel
%% and generate an error if any binary aliases are found.
%% We generate an error even if is obvious that the overall pattern can't
%% possibly match, for instance, {a,<<A:8>>,c}={x,<<A:8>>} WILL generate an
%% error.
+%% Maps should reject unbound variables here.
-reject_bin_alias({bin,Line,_}, {bin,_,_}, St) ->
+reject_invalid_alias({bin,Line,_}, {bin,_,_}, _, St) ->
add_error(Line, illegal_bin_pattern, St);
-reject_bin_alias({cons,_,H1,T1}, {cons,_,H2,T2}, St0) ->
- St = reject_bin_alias(H1, H2, St0),
- reject_bin_alias(T1, T2, St);
-reject_bin_alias({tuple,_,Es1}, {tuple,_,Es2}, St) ->
- reject_bin_alias_list(Es1, Es2, St);
-reject_bin_alias({record,_,Name1,Pfs1}, {record,_,Name2,Pfs2},
+reject_invalid_alias({map,_Line,Ps1}, {map,_,Ps2}, Vt, St0) ->
+ Fun = fun ({map_field_exact,L,{var,_,K},_V}, Sti) ->
+ case is_var_bound(K,Vt) of
+ true ->
+ Sti;
+ false ->
+ add_error(L, {unbound_var,K}, Sti)
+ end;
+ ({map_field_exact,_L,_K,_V}, Sti) ->
+ Sti
+ end,
+ foldl(Fun, foldl(Fun, St0, Ps1), Ps2);
+reject_invalid_alias({cons,_,H1,T1}, {cons,_,H2,T2}, Vt, St0) ->
+ St = reject_invalid_alias(H1, H2, Vt, St0),
+ reject_invalid_alias(T1, T2, Vt, St);
+reject_invalid_alias({tuple,_,Es1}, {tuple,_,Es2}, Vt, St) ->
+ reject_invalid_alias_list(Es1, Es2, Vt, St);
+reject_invalid_alias({record,_,Name1,Pfs1}, {record,_,Name2,Pfs2}, Vt,
#lint{records=Recs}=St) ->
case {dict:find(Name1, Recs),dict:find(Name2, Recs)} of
{{ok,{_Line1,Fields1}},{ok,{_Line2,Fields2}}} ->
- reject_bin_alias_rec(Pfs1, Pfs2, Fields1, Fields2, St);
+ reject_invalid_alias_rec(Pfs1, Pfs2, Fields1, Fields2, Vt, St);
{_,_} ->
%% One or more non-existing records. (An error messages has
%% already been generated, so we are done here.)
St
end;
-reject_bin_alias({match,_,P1,P2}, P, St0) ->
- St = reject_bin_alias(P1, P, St0),
- reject_bin_alias(P2, P, St);
-reject_bin_alias(P, {match,_,_,_}=M, St) ->
- reject_bin_alias(M, P, St);
-reject_bin_alias(_P1, _P2, St) -> St.
-
-reject_bin_alias_list([E1|Es1], [E2|Es2], St0) ->
- St = reject_bin_alias(E1, E2, St0),
- reject_bin_alias_list(Es1, Es2, St);
-reject_bin_alias_list(_, _, St) -> St.
-
-reject_bin_alias_rec(PfsA0, PfsB0, FieldsA0, FieldsB0, St) ->
+reject_invalid_alias({match,_,P1,P2}, P, Vt, St0) ->
+ St = reject_invalid_alias(P1, P, Vt, St0),
+ reject_invalid_alias(P2, P, Vt, St);
+reject_invalid_alias(P, {match,_,_,_}=M, Vt, St) ->
+ reject_invalid_alias(M, P, Vt, St);
+reject_invalid_alias(_P1, _P2, _Vt, St) -> St.
+
+reject_invalid_alias_list([E1|Es1], [E2|Es2], Vt, St0) ->
+ St = reject_invalid_alias(E1, E2, Vt, St0),
+ reject_invalid_alias_list(Es1, Es2, Vt, St);
+reject_invalid_alias_list(_, _, _, St) -> St.
+
+reject_invalid_alias_rec(PfsA0, PfsB0, FieldsA0, FieldsB0, Vt, St) ->
%% We treat records as if they have been converted to tuples.
PfsA1 = rbia_field_vars(PfsA0),
PfsB1 = rbia_field_vars(PfsB0),
@@ -1582,7 +1603,7 @@ reject_bin_alias_rec(PfsA0, PfsB0, FieldsA0, FieldsB0, St) ->
D = sofs:projection({external,fun({_,_,P1,_,P2}) -> {P1,P2} end}, C),
E = sofs:to_external(D),
{Ps1,Ps2} = lists:unzip(E),
- reject_bin_alias_list(Ps1, Ps2, St).
+ reject_invalid_alias_list(Ps1, Ps2, Vt, St).
rbia_field_vars(Fs) ->
[{Name,Pat} || {record_field,_,{atom,_,Name},Pat} <- Fs].
@@ -2284,7 +2305,7 @@ expr({'catch',Line,E}, Vt, St0) ->
expr({match,_Line,P,E}, Vt, St0) ->
{Evt,St1} = expr(E, Vt, St0),
{Pvt,Bvt,St2} = pattern(P, vtupdate(Evt, Vt), St1),
- St = reject_bin_alias_expr(P, E, St2),
+ St = reject_invalid_alias_expr(P, E, Vt, St2),
{vtupdate(Bvt, vtmerge(Evt, Pvt)),St};
%% No comparison or boolean operators yet.
expr({op,_Line,_Op,A}, Vt, St) ->
@@ -2381,7 +2402,7 @@ is_valid_call(Call) ->
_ -> true
end.
-%% is_valid_map_key(K,St) -> true | false
+%% is_valid_map_key(K) -> true | false
%% variables are allowed for patterns only at the top of the tree
is_valid_map_key({var,_,_}) -> true;
@@ -3413,6 +3434,14 @@ warn_unused_vars(U, Vt, St0) ->
UVt = map(fun ({V,{State,_,Ls}}) -> {V,{State,used,Ls}} end, U),
{vtmerge(Vt, UVt), St1}.
+
+is_var_bound(V, Vt) ->
+ case orddict:find(V, Vt) of
+ {ok,{bound,_Usage,_}} -> true;
+ _ -> false
+ end.
+
+
%% vtupdate(UpdVarTable, VarTable) -> VarTable.
%% Add the variables in the updated vartable to VarTable. The variables
%% will be updated with their property in UpdVarTable. The state of
--
2.1.4
