From 8f512f3f6d5d69403be4b8179bd80ba64229e761 Mon Sep 17 00:00:00 2001
From: Jeff Bezanson <jeff.bezanson@gmail.com>
Date: Sat, 9 May 2020 14:32:33 -0400
Subject: [PATCH] fix #35793, assertion failure with union of singletons
 (#35812)

---
 src/cgutils.cpp |  2 +-
 test/core.jl    | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/cgutils.cpp b/src/cgutils.cpp
index 87c3b5ee75f34..d23bf9c20e7e6 100644
--- a/src/cgutils.cpp
+++ b/src/cgutils.cpp
@@ -702,7 +702,7 @@ static Type *_julia_struct_to_llvm(jl_codegen_params_t *ctx, jl_value_t *jt, jl_
                 Type *AlignmentType = IntegerType::get(jl_LLVMContext, 8 * al);
                 unsigned NumATy = fsz / al;
                 unsigned remainder = fsz % al;
-                assert(NumATy > 0);
+                assert(al == 1 || NumATy > 0);
                 while (NumATy--)
                     latypes.push_back(AlignmentType);
                 while (remainder--)
diff --git a/test/core.jl b/test/core.jl
index da814873820fd..98344bfb44506 100644
--- a/test/core.jl
+++ b/test/core.jl
@@ -5961,6 +5961,16 @@ let a33709 = A33709(A33709(nothing))
     @test isnothing(a33709.a.a)
 end
 
+# issue #35793
+struct A35793
+    x::Union{Nothing, Missing}
+end
+let x = A35793(nothing), y = A35793(missing)
+    @test x isa A35793
+    @test x.x === nothing
+    @test y.x === missing
+end
+
 # issue 31583
 a31583 = "a"
 f31583() = a31583 === "a"