Merge branch 'john/compiler/misc-validator-fixes/ERL-832'

* john/compiler/misc-validator-fixes/ERL-832:
  Make the beam_validator smarter again, again

2 files changed, 18 insertions, 1 deletions

diff --git a/lib/compiler/src/beam_validator.erl b/lib/compiler/src/beam_validator.erl
index 15ed267c54..4081e366a5 100644
--- a/lib/compiler/src/beam_validator.erl
+++ b/lib/compiler/src/beam_validator.erl
@@ -871,7 +871,7 @@ valfun_4({test,is_map,{f,Lbl},[Src]}, Vst0) ->
 valfun_4({test,is_nil,{f,Lbl},[Src]}, Vst0) ->
     Vst = case get_term_type(Src, Vst0) of
               list ->
-                  branch_state(Lbl, set_type_reg(cons, Src, Vst0));
+                  branch_state(Lbl, set_aliased_type(cons, Src, Vst0));
               _ ->
                   branch_state(Lbl, Vst0)
           end,
diff --git a/lib/compiler/test/beam_validator_SUITE.erl b/lib/compiler/test/beam_validator_SUITE.erl
index c9df066958..585d0e7191 100644
--- a/lib/compiler/test/beam_validator_SUITE.erl
+++ b/lib/compiler/test/beam_validator_SUITE.erl
@@ -586,6 +586,9 @@ aliased_types(Config) ->
     {1,1} = aliased_types_2(Seq),
     {42,none} = aliased_types_2([]),
 
+    gurka = aliased_types_3([gurka]),
+    gaffel = aliased_types_3([gaffel]),
+
     ok.
 
 %% ERL-735: validator failed to track types on aliased registers, rejecting
@@ -614,6 +617,20 @@ aliased_types_2(Bug) ->
              _ -> hd(Bug)
          end}.
 
+%% ERL-832 part deux; validator failed to realize that an aliased register was
+%% a cons.
+aliased_types_3(Bug) ->
+    List = [Y || Y <- Bug],
+    case List of
+        [] -> Bug;
+        _ ->
+            if
+                hd(List) -> a:a();
+                true -> ok
+            end,
+            hd(List)
+    end.
+
 %%%-------------------------------------------------------------------------
 
 transform_remove(Remove, Module) ->