1 files changed, 81 insertions, 1 deletions
diff --git a/lib/hipe/cerl/erl_types.erl b/lib/hipe/cerl/erl_types.erl
index 56ec757dbf..cd2d2fe207 100644
--- a/lib/hipe/cerl/erl_types.erl
+++ b/lib/hipe/cerl/erl_types.erl
@@ -2712,7 +2712,87 @@ is_compat_args([], []) -> true;
 is_compat_args(_, _) -> false.
 
 is_compat_arg(A, A) -> true;
-is_compat_arg(A1, A2) -> t_is_any(A1) orelse t_is_any(A2).
+is_compat_arg(A1, A2) ->
+  is_specialization(A1, A2) orelse is_specialization(A2, A1).
+
+-spec is_specialization(erl_type(), erl_type()) -> boolean().
+
+%% Returns true if the first argument is a specialization of the
+%% second argument in the sense that every type is a specialization of
+%% any(). For example, {_,_} is a specialization of any(), but not of
+%% tuple(). Does not handle variables, but any() and unions (sort of).
+
+is_specialization(_, ?any) -> true;
+is_specialization(?any, _) -> false;
+is_specialization(?function(Domain1, Range1), ?function(Domain2, Range2)) ->
+  (is_specialization(Domain1, Domain2) andalso
+   is_specialization(Range1, Range2));
+is_specialization(?list(Contents1, Termination1, Size1),
+                  ?list(Contents2, Termination2, Size2)) ->
+  (Size1 =:= Size2 andalso
+   is_specialization(Contents1, Contents2) andalso
+   is_specialization(Termination1, Termination2));
+is_specialization(?product(Types1), ?product(Types2)) ->
+  specialization_list(Types1, Types2);
+is_specialization(?tuple(?any, ?any, ?any), ?tuple(_, _, _)) -> false;
+is_specialization(?tuple(_, _, _), ?tuple(?any, ?any, ?any)) -> false;
+is_specialization(?tuple(Elements1, Arity, _), 
+                  ?tuple(Elements2, Arity, _)) when Arity =/= ?any ->
+  specialization_list(Elements1, Elements2);
+is_specialization(?tuple_set([{Arity, List}]), 
+                  ?tuple(Elements2, Arity, _)) when Arity =/= ?any ->
+  specialization_list(sup_tuple_elements(List), Elements2);
+is_specialization(?tuple(Elements1, Arity, _),
+                  ?tuple_set([{Arity, List}])) when Arity =/= ?any ->
+  specialization_list(Elements1, sup_tuple_elements(List));
+is_specialization(?tuple_set(List1), ?tuple_set(List2)) ->
+  try
+    specialization_list(lists:append([T || {_Arity, T} <- List1]),
+                        lists:append([T || {_Arity, T} <- List2]))
+  catch _:_ -> false
+  end;
+is_specialization(?union(List1)=T1, ?union(List2)=T2) ->
+  case specialization_union2(T1, T2) of
+    {yes, Type1, Type2} -> is_specialization(Type1, Type2);
+    no -> specialization_list(List1, List2)
+  end;
+is_specialization(?union(List), T2) ->
+  case unify_union(List) of
+      {yes, Type} -> is_specialization(Type, T2);
+      no -> false
+  end;
+is_specialization(T1, ?union(List)) ->
+  case unify_union(List) of
+      {yes, Type} -> is_specialization(T1, Type);
+      no -> false
+  end;
+is_specialization(?opaque(_) = T1, T2) ->
+  is_specialization(t_opaque_structure(T1), T2);
+is_specialization(T1, ?opaque(_) = T2) ->
+  is_specialization(T1, t_opaque_structure(T2));
+is_specialization(?var(_), _) -> exit(error);
+is_specialization(_, ?var(_)) -> exit(error);
+is_specialization(T, T) -> true;
+is_specialization(?none, _) -> false;
+is_specialization(_, ?none) -> false;
+is_specialization(?unit, _) -> false;
+is_specialization(_, ?unit) -> false;
+is_specialization(#c{}, #c{}) -> false.
+
+specialization_list(L1, L2) ->
+  length(L1) =:= length(L2) andalso specialization_list1(L1, L2).
+
+specialization_list1([], []) -> true;
+specialization_list1([T1|L1], [T2|L2]) ->
+  is_specialization(T1, T2) andalso specialization_list1(L1, L2).
+
+specialization_union2(?union(List1)=T1, ?union(List2)=T2) ->
+  case {unify_union(List1), unify_union(List2)} of
+    {{yes, Type1}, {yes, Type2}} -> {yes, Type1, Type2};
+    {{yes, Type1}, no} -> {yes, Type1, T2};
+    {no, {yes, Type2}} -> {yes, T1, Type2};
+    {no, no} -> no
+  end.
 
 -spec t_inf_lists([erl_type()], [erl_type()]) -> [erl_type()].