Use @ in variable names generated by core and kernel

The previous variable names can be generated by
projects like LFE and Elixir, leading to possible
conflicts. Our first to choice to solve such conflicts
was to use $ but that's not a valid variable name in core.
Therefore we picked @ which is currently supported and
still reduces the chance of conflicts.

5 files changed, 21 insertions, 19 deletions

diff --git a/lib/compiler/src/sys_core_fold.erl b/lib/compiler/src/sys_core_fold.erl
index caa30a5ef4..00fb420d5f 100644
--- a/lib/compiler/src/sys_core_fold.erl
+++ b/lib/compiler/src/sys_core_fold.erl
@@ -2109,7 +2109,7 @@ make_var(A) ->
 make_var_name() ->
     N = get(new_var_num),
     put(new_var_num, N+1),
-    list_to_atom("fol"++integer_to_list(N)).
+    list_to_atom("@f"++integer_to_list(N)).
 
 letify(Bs, Body) ->
     Ann = cerl:get_ann(Body),
diff --git a/lib/compiler/src/v3_core.erl b/lib/compiler/src/v3_core.erl
index b96d3df8fe..f40cf97f57 100644
--- a/lib/compiler/src/v3_core.erl
+++ b/lib/compiler/src/v3_core.erl
@@ -1958,7 +1958,7 @@ new_fun_name(Type, #core{fcount=C}=St) ->
 %% new_var_name(State) -> {VarName,State}.
 
 new_var_name(#core{vcount=C}=St) ->
-    {list_to_atom("cor" ++ integer_to_list(C)),St#core{vcount=C + 1}}.
+    {list_to_atom("@c" ++ integer_to_list(C)),St#core{vcount=C + 1}}.
 
 %% new_var(State) -> {{var,Name},State}.
 %% new_var(LineAnno, State) -> {{var,Name},State}.
diff --git a/lib/compiler/src/v3_kernel.erl b/lib/compiler/src/v3_kernel.erl
index b4bbc5e739..cd42700365 100644
--- a/lib/compiler/src/v3_kernel.erl
+++ b/lib/compiler/src/v3_kernel.erl
@@ -880,7 +880,7 @@ new_fun_name(Type, #kern{func={F,Arity},fcount=C}=St) ->
 %% new_var_name(State) -> {VarName,State}.
 
 new_var_name(#kern{vcount=C}=St) ->
-    {list_to_atom("ker" ++ integer_to_list(C)),St#kern{vcount=C+1}}.
+    {list_to_atom("@k" ++ integer_to_list(C)),St#kern{vcount=C+1}}.
 
 %% new_var(State) -> {#k_var{},State}.
 
diff --git a/lib/dialyzer/src/dialyzer_dataflow.erl b/lib/dialyzer/src/dialyzer_dataflow.erl
index 963c953447..c0372a47e8 100644
--- a/lib/dialyzer/src/dialyzer_dataflow.erl
+++ b/lib/dialyzer/src/dialyzer_dataflow.erl
@@ -3585,6 +3585,7 @@ format_arg(Arg) ->
       case cerl:var_name(Arg) of
 	Atom when is_atom(Atom) ->
 	  case atom_to_list(Atom) of
+	    "@"++_ -> Default;
 	    "cor"++_ -> Default;
 	    "rec"++_ -> Default;
 	    Name -> Name ++ "::"
@@ -3645,6 +3646,7 @@ map_pats(Pats) ->
 		case cerl:var_name(Tree) of
 		  Atom when is_atom(Atom) ->
 		    case atom_to_list(Atom) of
+		      "@"++_ -> cerl:c_var('');
 		      "cor"++_ -> cerl:c_var('');
 		      "rec"++_ -> cerl:c_var('');
 		      _ -> cerl:set_ann(Tree, [])
diff --git a/lib/dialyzer/test/small_SUITE_data/results/fun_arity b/lib/dialyzer/test/small_SUITE_data/results/fun_arity
index cc9db65152..e916b2483f 100644
--- a/lib/dialyzer/test/small_SUITE_data/results/fun_arity
+++ b/lib/dialyzer/test/small_SUITE_data/results/fun_arity
@@ -1,37 +1,37 @@
 
-fun_arity.erl:100: Fun application will fail since _cor1 :: fun(() -> any()) is not a function of arity 1
+fun_arity.erl:100: Fun application will fail since _@c1 :: fun(() -> any()) is not a function of arity 1
 fun_arity.erl:100: Function 'Mfa_0_ko'/1 has no local return
-fun_arity.erl:104: Fun application will fail since _cor1 :: fun((_) -> any()) is not a function of arity 0
+fun_arity.erl:104: Fun application will fail since _@c1 :: fun((_) -> any()) is not a function of arity 0
 fun_arity.erl:104: Function 'Mfa_1_ko'/1 has no local return
-fun_arity.erl:111: Fun application will fail since _cor1 :: fun(() -> any()) is not a function of arity 1
+fun_arity.erl:111: Fun application will fail since _@c1 :: fun(() -> any()) is not a function of arity 1
 fun_arity.erl:111: Function mFa_0_ko/1 has no local return
-fun_arity.erl:115: Fun application will fail since _cor1 :: fun((_) -> any()) is not a function of arity 0
+fun_arity.erl:115: Fun application will fail since _@c1 :: fun((_) -> any()) is not a function of arity 0
 fun_arity.erl:115: Function mFa_1_ko/1 has no local return
-fun_arity.erl:122: Fun application will fail since _cor2 :: fun(() -> any()) is not a function of arity 1
+fun_arity.erl:122: Fun application will fail since _@c2 :: fun(() -> any()) is not a function of arity 1
 fun_arity.erl:122: Function 'MFa_0_ko'/2 has no local return
-fun_arity.erl:126: Fun application will fail since _cor2 :: fun((_) -> any()) is not a function of arity 0
+fun_arity.erl:126: Fun application will fail since _@c2 :: fun((_) -> any()) is not a function of arity 0
 fun_arity.erl:126: Function 'MFa_1_ko'/2 has no local return
-fun_arity.erl:35: Fun application will fail since _cor0 :: fun(() -> 'ok') is not a function of arity 1
+fun_arity.erl:35: Fun application will fail since _@c0 :: fun(() -> 'ok') is not a function of arity 1
 fun_arity.erl:35: Function f_0_ko/0 has no local return
-fun_arity.erl:39: Fun application will fail since _cor0 :: fun((_) -> 'ok') is not a function of arity 0
+fun_arity.erl:39: Fun application will fail since _@c0 :: fun((_) -> 'ok') is not a function of arity 0
 fun_arity.erl:39: Function f_1_ko/0 has no local return
-fun_arity.erl:48: Fun application will fail since _cor0 :: fun(() -> 'ok') is not a function of arity 1
+fun_arity.erl:48: Fun application will fail since _@c0 :: fun(() -> 'ok') is not a function of arity 1
 fun_arity.erl:48: Function fa_0_ko/0 has no local return
-fun_arity.erl:53: Fun application will fail since _cor0 :: fun((_) -> 'ok') is not a function of arity 0
+fun_arity.erl:53: Fun application will fail since _@c0 :: fun((_) -> 'ok') is not a function of arity 0
 fun_arity.erl:53: Function fa_1_ko/0 has no local return
-fun_arity.erl:63: Fun application will fail since _cor0 :: fun(() -> any()) is not a function of arity 1
+fun_arity.erl:63: Fun application will fail since _@c0 :: fun(() -> any()) is not a function of arity 1
 fun_arity.erl:63: Function mfa_0_ko/0 has no local return
-fun_arity.erl:68: Fun application will fail since _cor0 :: fun((_) -> any()) is not a function of arity 0
+fun_arity.erl:68: Fun application will fail since _@c0 :: fun((_) -> any()) is not a function of arity 0
 fun_arity.erl:68: Function mfa_1_ko/0 has no local return
-fun_arity.erl:76: Fun application will fail since _cor0 :: fun(() -> any()) is not a function of arity 1
+fun_arity.erl:76: Fun application will fail since _@c0 :: fun(() -> any()) is not a function of arity 1
 fun_arity.erl:76: Function mfa_ne_0_ko/0 has no local return
 fun_arity.erl:78: Function mf_ne/0 will never be called
-fun_arity.erl:81: Fun application will fail since _cor0 :: fun((_) -> any()) is not a function of arity 0
+fun_arity.erl:81: Fun application will fail since _@c0 :: fun((_) -> any()) is not a function of arity 0
 fun_arity.erl:81: Function mfa_ne_1_ko/0 has no local return
 fun_arity.erl:83: Function mf_ne/1 will never be called
-fun_arity.erl:89: Fun application will fail since _cor0 :: fun(() -> any()) is not a function of arity 1
+fun_arity.erl:89: Fun application will fail since _@c0 :: fun(() -> any()) is not a function of arity 1
 fun_arity.erl:89: Function mfa_nd_0_ko/0 has no local return
 fun_arity.erl:90: Call to missing or unexported function fun_arity:mf_nd/0
-fun_arity.erl:93: Fun application will fail since _cor0 :: fun((_) -> any()) is not a function of arity 0
+fun_arity.erl:93: Fun application will fail since _@c0 :: fun((_) -> any()) is not a function of arity 0
 fun_arity.erl:93: Function mfa_nd_1_ko/0 has no local return
 fun_arity.erl:94: Call to missing or unexported function fun_arity:mf_nd/1