From 436671f5b230ac230c817780552df9fd7b782b8f Mon Sep 17 00:00:00 2001
From: Julien Couvreur <jcouv@users.noreply.github.com>
Date: Thu, 13 Dec 2018 19:03:22 -0800
Subject: [PATCH] Use Equals to compare array types in attributes (#31741)

---
 .../Portable/Binder/Binder_Attributes.cs      |  4 +-
 .../Semantics/NullableReferenceTypesTests.cs  | 79 +++++++++++++++++++
 .../Test/Emit/CodeGen/CodeGenTuples.vb        | 25 ++++++
 3 files changed, 107 insertions(+), 1 deletion(-)

diff --git a/src/Compilers/CSharp/Portable/Binder/Binder_Attributes.cs b/src/Compilers/CSharp/Portable/Binder/Binder_Attributes.cs
index a5d16ccba06..c50a272516e 100644
--- a/src/Compilers/CSharp/Portable/Binder/Binder_Attributes.cs
+++ b/src/Compilers/CSharp/Portable/Binder/Binder_Attributes.cs
@@ -625,7 +625,9 @@ private TypeSymbol BindNamedAttributeArgumentType(AttributeArgumentSyntax namedA
                     {
                         hasErrors = true;
                     }
-                    else if (reorderedArgument.Kind == TypedConstantKind.Array && parameter.Type.TypeKind == TypeKind.Array && (TypeSymbol)reorderedArgument.Type != parameter.Type.TypeSymbol)
+                    else if (reorderedArgument.Kind == TypedConstantKind.Array &&
+                        parameter.Type.TypeKind == TypeKind.Array &&
+                        !((TypeSymbol)reorderedArgument.Type).Equals(parameter.Type.TypeSymbol, TypeCompareKind.AllIgnoreOptions))
                     {
                         // NOTE: As in dev11, we don't allow array covariance conversions (presumably, we don't have a way to
                         // represent the conversion in metadata).
diff --git a/src/Compilers/CSharp/Test/Semantic/Semantics/NullableReferenceTypesTests.cs b/src/Compilers/CSharp/Test/Semantic/Semantics/NullableReferenceTypesTests.cs
index c4a178f5897..dd379807813 100644
--- a/src/Compilers/CSharp/Test/Semantic/Semantics/NullableReferenceTypesTests.cs
+++ b/src/Compilers/CSharp/Test/Semantic/Semantics/NullableReferenceTypesTests.cs
@@ -445,6 +445,85 @@ static void F2(object? w)
                 Diagnostic(ErrorCode.WRN_MissingNonNullTypesContextForAnnotation, "?").WithLocation(14, 26));
         }
 
+        [Fact, WorkItem(31740, "https://github.com/dotnet/roslyn/issues/31740")]
+        public void Attribute_ArrayWithDifferentNullability()
+        {
+            var source =
+@"
+public class MyAttribute : System.Attribute
+{
+    public MyAttribute(string[] x) { }
+}
+#nullable enable
+[My(new string[] { ""hello"" })]
+class C { }
+";
+            var comp = CreateCompilation(source, options: TestOptions.DebugDll);
+            comp.VerifyDiagnostics();
+        }
+
+        [Fact, WorkItem(31740, "https://github.com/dotnet/roslyn/issues/31740")]
+        public void Attribute_ArrayWithDifferentNullability2()
+        {
+            var source =
+@"
+public class MyAttribute : System.Attribute
+{
+    public MyAttribute(string[] x) { }
+}
+#nullable enable
+[My(new string[] { null })]
+class C { }
+";
+            var comp = CreateCompilation(source, options: TestOptions.DebugDll);
+            comp.VerifyDiagnostics();
+            // Expecting a warning. Issue tracked by https://github.com/dotnet/roslyn/issues/23697
+        }
+
+        [Fact, WorkItem(31740, "https://github.com/dotnet/roslyn/issues/31740")]
+        public void Attribute_ArrayWithDifferentNullability_DynamicAndTupleNames()
+        {
+            var source = @"
+public class MyAttribute : System.Attribute
+{
+    public MyAttribute((string alice, string)[] x, dynamic[] y, object[] z) { }
+}
+#nullable enable
+[My(new (string, string bob)[] { }, new object[] { }, new dynamic[] { })]
+class C { }
+";
+            var comp = CreateCompilation(source, options: TestOptions.DebugDll);
+            comp.VerifyDiagnostics(
+                // (7,2): error CS0181: Attribute constructor parameter 'x' has type '(string alice, string)[]', which is not a valid attribute parameter type
+                // [My(new (string, string bob)[] { }, new object[] { }, new dynamic[] { })]
+                Diagnostic(ErrorCode.ERR_BadAttributeParamType, "My").WithArguments("x", "(string alice, string)[]").WithLocation(7, 2),
+                // (7,2): error CS0181: Attribute constructor parameter 'y' has type 'dynamic[]', which is not a valid attribute parameter type
+                // [My(new (string, string bob)[] { }, new object[] { }, new dynamic[] { })]
+                Diagnostic(ErrorCode.ERR_BadAttributeParamType, "My").WithArguments("y", "dynamic[]").WithLocation(7, 2)
+                );
+        }
+
+        [Fact, WorkItem(31740, "https://github.com/dotnet/roslyn/issues/31740")]
+        public void Attribute_ArrayWithDifferentNullability_Dynamic()
+        {
+            var source =
+@"
+public class MyAttribute : System.Attribute
+{
+    public MyAttribute(dynamic[] y) { }
+}
+#nullable enable
+[My(new object[] { })]
+class C { }
+";
+            var comp = CreateCompilation(source, options: TestOptions.DebugDll);
+            comp.VerifyDiagnostics(
+                // (7,2): error CS0181: Attribute constructor parameter 'y' has type 'dynamic[]', which is not a valid attribute parameter type
+                // [My(new object[] { })]
+                Diagnostic(ErrorCode.ERR_BadAttributeParamType, "My").WithArguments("y", "dynamic[]").WithLocation(7, 2)
+                );
+        }
+
         [Fact]
         public void NullableAndConditionalOperators()
         {
diff --git a/src/Compilers/VisualBasic/Test/Emit/CodeGen/CodeGenTuples.vb b/src/Compilers/VisualBasic/Test/Emit/CodeGen/CodeGenTuples.vb
index 02af9946306..98adac8db53 100644
--- a/src/Compilers/VisualBasic/Test/Emit/CodeGen/CodeGenTuples.vb
+++ b/src/Compilers/VisualBasic/Test/Emit/CodeGen/CodeGenTuples.vb
@@ -109,6 +109,31 @@ Namespace System
 End Namespace
 "
 
+        <Fact>
+        Public Sub TupleNamesInArrayInAttribute()
+
+            Dim comp = CreateCompilation(
+<compilation>
+    <file name="a.vb"><![CDATA[
+Imports System
+<My(New (String, bob As String)() { })>
+Public Class MyAttribute
+    Inherits System.Attribute
+
+    Public Sub New(x As (alice As String, String)())
+    End Sub
+End Class
+    ]]></file>
+</compilation>)
+
+            comp.AssertTheseDiagnostics(<errors><![CDATA[
+BC30045: Attribute constructor has a parameter of type '(alice As String, String)()', which is not an integral, floating-point or Enum type or one of Object, Char, String, Boolean, System.Type or 1-dimensional array of these types.
+<My(New (String, bob As String)() { })>
+ ~~
+                                        ]]></errors>)
+
+        End Sub
+
         <Fact>
         Public Sub TupleTypeBinding()
 
-- 
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