From 4c549350df8467a59f49b8e64f82fb34de86c4a6 Mon Sep 17 00:00:00 2001
From: Jeff Bezanson <jeff.bezanson@gmail.com>
Date: Thu, 11 May 2017 10:40:59 -0400
Subject: [PATCH] fix #21793, regression in serializing nested closure

---
 base/serialize.jl | 3 ++-
 test/serialize.jl | 9 +++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/base/serialize.jl b/base/serialize.jl
index 4b309489226c9..d453e9e0a33f9 100644
--- a/base/serialize.jl
+++ b/base/serialize.jl
@@ -703,7 +703,8 @@ function handle_deserialize(s::AbstractSerializer, b::Int32)
         return GlobalRef(deserialize(s)::Module, deserialize(s)::Symbol)
     elseif b == FULL_GLOBALREF_TAG
         ty = deserialize(s)
-        return GlobalRef(ty.name.module, ty.name.name)
+        tn = unwrap_unionall(ty).name
+        return GlobalRef(tn.module, tn.name)
     elseif b == LONGTUPLE_TAG
         return deserialize_tuple(s, Int(read(s.io, Int32)::Int32))
     elseif b == LONGEXPR_TAG
diff --git a/test/serialize.jl b/test/serialize.jl
index 8be0c8f0d0a35..b136ad7b40425 100644
--- a/test/serialize.jl
+++ b/test/serialize.jl
@@ -300,6 +300,15 @@ main_ex = quote
         $Test.@test g2() == :magic_token_anon_fun_test
         $Test.@test g2() == :magic_token_anon_fun_test
         $Test.@test deserialize(ds) === g2
+
+        # issue #21793
+        y = x -> (() -> x)
+        seekstart(s)
+        serialize(s, y)
+        seekstart(s)
+        y2 = deserialize(s)
+        x2 = y2(2)
+        $Test.@test x2() == 2
     end
 end
 # This needs to be run on `Main` since the serializer treats it differently.