From 3f9c5ef8162bc203bd6eb92d0b8b5da0990f2c0f Mon Sep 17 00:00:00 2001
From: Charles Stoner <chucks@microsoft.com>
Date: Thu, 5 Jul 2018 10:48:15 -0700
Subject: [PATCH] Ensure TypeSymbolWithAnnotations.IsNullable != null for value
 type (#28298)

---
 .../Portable/Symbols/SymbolWithAnnotations.cs     |  2 +-
 .../Test/Semantic/Semantics/StaticNullChecking.cs | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/Compilers/CSharp/Portable/Symbols/SymbolWithAnnotations.cs b/src/Compilers/CSharp/Portable/Symbols/SymbolWithAnnotations.cs
index b2c208d8eca..5f4a37e3de8 100644
--- a/src/Compilers/CSharp/Portable/Symbols/SymbolWithAnnotations.cs
+++ b/src/Compilers/CSharp/Portable/Symbols/SymbolWithAnnotations.cs
@@ -566,7 +566,7 @@ public bool ApplyNullableTransforms(ImmutableArray<bool> transforms, bool useNon
                 result = result.DoUpdate(newTypeSymbol, result.CustomModifiers);
             }
 
-            //if (!result.IsValueType) // PROTOTYPE(NullableReferenceTypes): this is causing cycle 6 in NullableAttribute_01
+            if (!result.IsValueType)
             {
                 if (isNullable)
                 {
diff --git a/src/Compilers/CSharp/Test/Semantic/Semantics/StaticNullChecking.cs b/src/Compilers/CSharp/Test/Semantic/Semantics/StaticNullChecking.cs
index 6c721754974..8823a860d77 100644
--- a/src/Compilers/CSharp/Test/Semantic/Semantics/StaticNullChecking.cs
+++ b/src/Compilers/CSharp/Test/Semantic/Semantics/StaticNullChecking.cs
@@ -1863,6 +1863,21 @@ public class Oblivious { }
             VerifyNonNullTypes(obliviousComp.GetMember("Oblivious"), true); // PROTOTYPE(NullableReferenceTypes): should be false
         }
 
+        [Fact]
+        public void NonNullTypes_ValueTypeArgument()
+        {
+            var source =
+@"using System.Runtime.CompilerServices;
+[module: NonNullTypes(false)]
+class A<T> { }
+class B
+{
+    A<byte> P { get; }
+}";
+            var comp = CreateCompilation(new[] { source, NonNullTypesAttributesDefinition }, parseOptions: TestOptions.Regular8);
+            comp.VerifyDiagnostics();
+        }
+
         [Fact]
         public void AssignObliviousIntoLocals()
         {
-- 
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