Add testcases for ms_transform warning and fix scoping

2 files changed, 127 insertions, 1 deletions

diff --git a/lib/stdlib/src/ms_transform.erl b/lib/stdlib/src/ms_transform.erl
index 1a571fc607..a249dea525 100644
--- a/lib/stdlib/src/ms_transform.erl
+++ b/lib/stdlib/src/ms_transform.erl
@@ -213,7 +213,7 @@ transform_from_shell(Dialect, Clauses, BoundEnvironment) ->
 %%
 parse_transform(Forms, _Options) ->
     SaveFilename = setup_filename(),
-    %io:format("~p~n",[Forms]),
+    %io:format("Forms: ~p~n",[Forms]),
     case catch forms(Forms) of
 	{'EXIT',Reason} ->
 	    cleanup_filename(SaveFilename),
@@ -340,11 +340,22 @@ copy({call,Line,{remote,_Line2,{record_field,_Line3,
 copy({call,Line,{remote,_Line2,{atom,_Line3,dbg},{atom,_Line4,fun2ms}},
       As0},Bound) ->
     {transform_call(dbg,Line,As0,Bound),Bound};
+copy({match,Line,A,B},Bound) ->
+    {B1,Bound1} = copy(B,Bound),
+    {A1,Bound2} = copy(A,Bound),
+    {{match,Line,A1,B1},gb_sets:union(Bound1,Bound2)};
 copy({var,_Line,'_'} = VarDef,Bound) ->
     {VarDef,Bound};
 copy({var,_Line,Name} = VarDef,Bound) ->
     Bound1 = gb_sets:add(Name,Bound),
     {VarDef,Bound1};
+copy({'fun',Line,{clauses,Clauses}},Bound) -> % Dont export bindings from funs
+    {NewClauses,_IgnoredBindings} = copy_list(Clauses,Bound),
+    {{'fun',Line,{clauses,NewClauses}},Bound};
+copy({'case',Line,Of,ClausesList},Bound) -> % Dont export bindings from funs
+    {NewOf,NewBind0} = copy(Of,Bound),
+    {NewClausesList,NewBindings} = copy_case_clauses(ClausesList,NewBind0,[]),
+    {{'case',Line,NewOf,NewClausesList},NewBindings};
 copy(T,Bound) when is_tuple(T) ->
     {L,Bound1} = copy_list(tuple_to_list(T),Bound),
     {list_to_tuple(L),Bound1};
@@ -353,6 +364,20 @@ copy(L,Bound) when is_list(L) ->
 copy(AnyOther,Bound) ->
     {AnyOther,Bound}.
 
+copy_case_clauses([],Bound,AddSets) ->
+    ReallyAdded = gb_sets:intersection(AddSets),
+    {[],gb_sets:union(Bound,ReallyAdded)};
+copy_case_clauses([{clause,Line,Match,Guard,Clauses}|T],Bound,AddSets) ->
+    {NewMatch,MatchBinds} = copy(Match,Bound),
+    {NewGuard,GuardBinds} = copy(Guard,MatchBinds), %% Really no new binds
+    {NewClauses,AllBinds} = copy(Clauses,GuardBinds),
+    %% To limit the setsizes, I subtract what I had before the case clause
+    %% and add it in the end
+    AddedBinds = gb_sets:subtract(AllBinds,Bound),
+    {NewTail,ExportedBindings} =
+	copy_case_clauses(T,Bound,[AddedBinds | AddSets]),
+    {[{clause,Line,NewMatch,NewGuard,NewClauses}|NewTail],ExportedBindings}.
+
 copy_list([H|T],Bound) ->
     {C1,Bound1} = copy(H,Bound),
     {C2,Bound2} = copy_list(T,Bound1),
diff --git a/lib/stdlib/test/ms_transform_SUITE.erl b/lib/stdlib/test/ms_transform_SUITE.erl
index 79a0a9af89..2d90d5b823 100644
--- a/lib/stdlib/test/ms_transform_SUITE.erl
+++ b/lib/stdlib/test/ms_transform_SUITE.erl
@@ -37,6 +37,7 @@
 -export([andalso_orelse/1]).
 -export([float_1_function/1]).
 -export([action_function/1]).
+-export([warnings/1]).
 -export([init_per_testcase/2, fin_per_testcase/2]).
 
 init_per_testcase(_Func, Config) ->
@@ -50,8 +51,90 @@ fin_per_testcase(_Func, Config) ->
 all(suite) -> [from_shell,basic_ets,basic_dbg,records,record_index,multipass,
 	       bitsyntax, record_defaults, andalso_orelse,
                float_1_function, action_function, 
+	       warnings,
 	       top_match, old_guards, autoimported, semicolon].
 
+%% This may be subject to change
+-define(WARN_NUMBER_SHADOW,50).
+warnings(suite) ->
+    [];
+warnings(doc) ->
+    ["Check that shadowed variables in fun head generate warning"];
+warnings(Config) when is_list(Config) ->
+    ?line setup(Config),
+    Prog = <<"A=5, "
+	    "ets:fun2ms(fun({A,B}) "
+	    "            when is_integer(A) and (A+5 > B) -> "
+	    "              A andalso B "
+	    "            end)">>,
+    ?line [{_,[{_,ms_transform,{?WARN_NUMBER_SHADOW,'A'}}]}] =
+	compile_ww(Prog),
+    Prog2 = <<"C=5, "
+	    "ets:fun2ms(fun({A,B} = C) "
+	    "            when is_integer(A) and (A+5 > B) -> "
+	    "              {A andalso B,C} "
+	    "            end)">>,
+    ?line [{_,[{_,ms_transform,{?WARN_NUMBER_SHADOW,'C'}}]}] =
+	compile_ww(Prog2),
+    Rec3 = <<"-record(a,{a,b,c,d=foppa}).">>,
+    Prog3 = <<"A=3,C=5, "
+	    "ets:fun2ms(fun(#a{a = A, b = B} = C) "
+	    "            when is_integer(A) and (A+5 > B) -> "
+	    "              {A andalso B,C} "
+	    "            end)">>,
+    ?line [{_,[{_,ms_transform,{?WARN_NUMBER_SHADOW,'A'}},
+	       {_,ms_transform,{?WARN_NUMBER_SHADOW,'C'}}]}] =
+	compile_ww(Rec3,Prog3),
+    Rec4 = <<"-record(a,{a,b,c,d=foppa}).">>,
+    Prog4 = <<"A=3,C=5, "
+	     "F = fun(B) -> B*3 end,"
+	     "erlang:display(F(A)),"
+	     "ets:fun2ms(fun(#a{a = A, b = B} = C) "
+	     "            when is_integer(A) and (A+5 > B) -> "
+	     "              {A andalso B,C} "
+	     "            end)">>,
+    ?line [{_,[{_,ms_transform,{?WARN_NUMBER_SHADOW,'A'}},
+	       {_,ms_transform,{?WARN_NUMBER_SHADOW,'C'}}]}] =
+	compile_ww(Rec4,Prog4),
+    Rec5 = <<"-record(a,{a,b,c,d=foppa}).">>,
+    Prog5 = <<"A=3,C=5, "
+	     "F = fun(B) -> B*3 end,"
+	     "erlang:display(F(A)),"
+	     "B = ets:fun2ms(fun(#a{a = A, b = B} = C) "
+	     "            when is_integer(A) and (A+5 > B) -> "
+	     "              {A andalso B,C} "
+	     "            end)">>,
+    ?line [{_,[{_,ms_transform,{?WARN_NUMBER_SHADOW,'A'}},
+	       {_,ms_transform,{?WARN_NUMBER_SHADOW,'C'}}]}] =
+	compile_ww(Rec5,Prog5),
+    Prog6 = <<"   X=bar, "
+	     "    A = case X of"
+	     "       foo ->"
+	     "          foo;"
+	     "       Y ->"
+	     "          ets:fun2ms(fun(Y) ->" % This is a warning
+	     "                         3*Y"
+	     "                     end)"
+	     "   end,"
+	     "   ets:fun2ms(fun(Y) ->" % Y out of "scope" here, so no warning
+	     "                  {3*Y,A}"
+	     "              end)">>,
+    ?line [{_,[{_,ms_transform,{?WARN_NUMBER_SHADOW,'Y'}}]}] =
+	compile_ww(Prog6),
+    Prog7 = <<"   X=bar, "
+	     "    A = case X of"
+	     "       foo ->"
+	     "          Y = foo;"
+	     "       Y ->"
+	     "          bar"
+	     "   end,"
+	     "   ets:fun2ms(fun(Y) ->" % Y exported from case and safe, so warn
+	     "                  {3*Y,A}"
+	     "              end)">>,
+    ?line [{_,[{_,ms_transform,{?WARN_NUMBER_SHADOW,'Y'}}]}] =
+	compile_ww(Prog7),
+    ok.
+
 andalso_orelse(suite) ->
     [];
 andalso_orelse(doc) ->
@@ -721,6 +804,24 @@ compile_and_run(Records,Expr) ->
     code:load_binary(tmp,FN,Bin),
     tmp:tmp().
 
+compile_ww(Expr) ->
+    compile_ww(<<>>,Expr).
+compile_ww(Records,Expr) ->
+    Prog = <<
+	"-module(tmp).\n",
+    "-include_lib(\"stdlib/include/ms_transform.hrl\").\n",
+    "-export([tmp/0]).\n",
+    Records/binary,"\n",
+    "tmp() ->\n",
+    Expr/binary,".\n">>,
+    FN=temp_name(),
+    file:write_file(FN,Prog),
+    {ok,Forms} = epp:parse_file(FN,"",""),
+    {ok,tmp,_Bin,Wlist} = compile:forms(Forms,[return_warnings,
+					       nowarn_unused_vars,
+					       nowarn_unused_record]),
+    Wlist.
+
 do_eval(String) ->
     {done,{ok,T,_},[]} = erl_scan:tokens(
 			   [],