Eliminate crash in beam_ssa_type

Closes #7179

1 files changed, 12 insertions, 5 deletions

diff --git a/lib/compiler/src/beam_call_types.erl b/lib/compiler/src/beam_call_types.erl
index 8b9cb836fd..697566cecb 100644
--- a/lib/compiler/src/beam_call_types.erl
+++ b/lib/compiler/src/beam_call_types.erl
@@ -365,12 +365,19 @@ types(erlang, is_boolean, [Type]) ->
 types(erlang, is_float, [Type]) ->
     sub_unsafe_type_test(Type, #t_float{});
 types(erlang, is_function, [Type, #t_integer{elements={Arity,Arity}}])
-  when Arity >= 0, Arity =< ?MAX_FUNC_ARGS ->
+  when is_integer(Arity) ->
     RetType =
-        case meet(Type, #t_fun{arity=Arity}) of
-            Type -> #t_atom{elements=[true]};
-            none -> #t_atom{elements=[false]};
-            _ -> beam_types:make_boolean()
+        if
+            Arity < 0 ->
+                none;
+            0 =< Arity, Arity =< ?MAX_FUNC_ARGS ->
+                case meet(Type, #t_fun{arity=Arity}) of
+                    Type -> #t_atom{elements=[true]};
+                    none -> #t_atom{elements=[false]};
+                    _ -> beam_types:make_boolean()
+                end;
+            Arity > ?MAX_FUNC_ARGS ->
+                #t_atom{elements=[false]}
         end,
     sub_unsafe(RetType, [any, any]);
 types(erlang, is_function, [Type]) ->