Fix a bug concerning record field types

The default value 'undefined' was added to records field types in such
a way that the result was not always a well-formed type. This bug has
been fixed.

---

erl_pp has since OTP-8150 formatted types so that 'undefined' was
removed from union types assigned to record fields. Since one cannot
distinguish between 'undefined' added by the parser or supplied by the
user, a side effect was that user supplied 'undefined's were also
removed.

Now the pretty printer shows 'undefined' even if added by the parser.
This is a minor issue.

3 files changed, 32 insertions, 12 deletions

diff --git a/lib/stdlib/src/erl_parse.yrl b/lib/stdlib/src/erl_parse.yrl
index bb4b18cf9b..15b45d72f4 100644
--- a/lib/stdlib/src/erl_parse.yrl
+++ b/lib/stdlib/src/erl_parse.yrl
@@ -2,7 +2,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2010. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2011. 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
@@ -757,7 +757,8 @@ record_fields([{typed,Expr,TypeInfo}|Fields]) ->
 	    {atom, La, _} ->
                 case has_undefined(TypeInfo) of
                     false ->
-                        lift_unions(abstract(undefined, La), TypeInfo);
+                        TypeInfo2 = maybe_add_paren(TypeInfo),
+                        lift_unions(abstract(undefined, La), TypeInfo2);
                     true ->
                         TypeInfo
                 end
@@ -778,6 +779,11 @@ has_undefined({type,_,union,Ts}) ->
 has_undefined(_) ->
     false.
 
+maybe_add_paren({ann_type,L,T}) ->
+    {paren_type,L,[{ann_type,L,T}]};
+maybe_add_paren(T) ->
+    T.
+
 term(Expr) ->
     try normalise(Expr)
     catch _:_R -> ret_err(?line(Expr), "bad attribute")
diff --git a/lib/stdlib/src/erl_pp.erl b/lib/stdlib/src/erl_pp.erl
index df4a20b833..66c80a45cb 100644
--- a/lib/stdlib/src/erl_pp.erl
+++ b/lib/stdlib/src/erl_pp.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2010. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2011. 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
@@ -558,17 +558,11 @@ record_field({typed_record_field,{record_field,_,F,Val},Type}, Hook) ->
     Fl = lexpr(F, L, Hook),
     Vl = typed(lexpr(Val, R, Hook), Type),
     {list,[{cstep,[Fl,' ='],Vl}]};
-record_field({typed_record_field,Field,Type0}, Hook) ->
-    Type = remove_undefined(Type0),
+record_field({typed_record_field,Field,Type}, Hook) ->
     typed(record_field(Field, Hook), Type);
 record_field({record_field,_,F}, Hook) ->
     lexpr(F, 0, Hook).
 
-remove_undefined({type,L,union,[{atom,_,undefined}|T]}) ->
-    {type,L,union,T};
-remove_undefined(T) -> % cannot happen
-    T.
-
 list({cons,_,H,T}, Es, Hook) ->
     list(T, [H|Es], Hook);
 list({nil,_}, Es, Hook) ->
diff --git a/lib/stdlib/test/erl_pp_SUITE.erl b/lib/stdlib/test/erl_pp_SUITE.erl
index 822886cb8a..bc811355ab 100644
--- a/lib/stdlib/test/erl_pp_SUITE.erl
+++ b/lib/stdlib/test/erl_pp_SUITE.erl
@@ -48,7 +48,7 @@
 	  neg_indent/1,
 
 	  otp_6321/1, otp_6911/1, otp_6914/1, otp_8150/1, otp_8238/1,
-	  otp_8473/1, otp_8522/1, otp_8567/1, otp_8664/1]).
+	  otp_8473/1, otp_8522/1, otp_8567/1, otp_8664/1, otp_9147/1]).
 
 %% Internal export.
 -export([ehook/6]).
@@ -79,7 +79,7 @@ groups() ->
      {attributes, [], [misc_attrs, import_export]},
      {tickets, [],
       [otp_6321, otp_6911, otp_6914, otp_8150, otp_8238,
-       otp_8473, otp_8522, otp_8567, otp_8664]}].
+       otp_8473, otp_8522, otp_8567, otp_8664, otp_9147]}].
 
 init_per_suite(Config) ->
     Config.
@@ -1047,6 +1047,26 @@ otp_8664(Config) when is_list(Config) ->
 
     ok.
 
+otp_9147(doc) ->
+    "OTP_9147. Create well-formed types when adding 'undefined'.";
+otp_9147(suite) -> [];
+otp_9147(Config) when is_list(Config) ->
+    FileName = filename('otp_9147.erl', Config),
+    C1 = <<"-module(otp_9147).\n"
+           "-export_type([undef/0]).\n"
+           "-record(undef, {f1 :: F1 :: a | b}).\n"
+           "-type undef() :: #undef{}.\n">>,
+    ?line ok = file:write_file(FileName, C1),
+    ?line {ok, _, []} = 
+       compile:file(FileName, [return,'P',{outdir,?privdir}]),
+    PFileName = filename('otp_9147.P', Config),
+    ?line {ok, Bin} = file:read_file(PFileName),
+    %% The parentheses around "F1 :: a | b" are new (bugfix).
+    ?line true = 
+        lists:member("-record(undef,{f1 :: undefined | (F1 :: a | b)}).",
+                     string:tokens(binary_to_list(Bin), "\n")),
+    ok.
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 compile(Config, Tests) ->