erl_types: Be less strict about subtyping in record field checks

erlang · Dec 19, 2024 · b9d542d · b9d542d
1 parent 0b71469
commit b9d542d
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Showing 2 changed files with 13 additions and 3 deletions.
diff --git a/lib/dialyzer/src/erl_types.erl b/lib/dialyzer/src/erl_types.erl
@@ -4632,9 +4632,9 @@ check_fields(RecName, [{type, _, field_type, [{atom, _, Name}, Abstr]}|Left],
   {Type, C1} = t_from_form(Abstr, ET, Site, MR, V, C),
   {Name, _, DeclType} = lists:keyfind(Name, 1, DeclFields),
   TypeNoVars = subst_all_vars_to_any(Type),
-  case t_is_subtype(TypeNoVars, DeclType) of
-    false -> {error, Name};
-    true -> check_fields(RecName, Left, DeclFields, S, C1)
+  case t_is_impossible(t_inf(TypeNoVars, DeclType)) of
+    true -> {error, Name};
+    false -> check_fields(RecName, Left, DeclFields, S, C1)
   end;
 check_fields(_RecName, [], _Decl, _S, C) ->
   C.

diff --git a/lib/dialyzer/test/small_SUITE_data/src/contracts_with_subtypes.erl b/lib/dialyzer/test/small_SUITE_data/src/contracts_with_subtypes.erl
@@ -298,3 +298,13 @@ factored_ets_new_t() ->
     factored_ets_new(name,{bag}),
     factored_ets_new(name,bag),
     ok.
+
+%===============================================================================
+
+-nominal t1() :: t2().
+-nominal t2() :: integer().
+-record(r, {t :: t1()}).
+
+-spec swap_r(#r{}) -> #r{t :: t2()}.
+swap_r(#r{t = T}) ->
+  #r{t = T}.