Allow VB Shared New to initialize a Shared field of another instance.

Fixes #1028
Closes #1116

src/Compilers/Test/Utilities/VisualBasic/TestOptions.vb

 ' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
-' TODO: Strict Module
+Imports System.Runtime.CompilerServices
+
 Public Class TestOptions
     Public Shared ReadOnly Script As New VisualBasicParseOptions(kind:=SourceCodeKind.Script)
     Public Shared ReadOnly Interactive As New VisualBasicParseOptions(kind:=SourceCodeKind.Interactive)
@@ -20,3 +21,15 @@ Public Class TestOptions
     Public Shared ReadOnly ReleaseModule As New VisualBasicCompilationOptions(OutputKind.NetModule, optimizationLevel:=OptimizationLevel.Release)
     Public Shared ReadOnly ReleaseWinMD As New VisualBasicCompilationOptions(OutputKind.WindowsRuntimeMetadata, optimizationLevel:=OptimizationLevel.Release)
 End Class
+
+Module TestOptionExtensions
+    <Extension()>
+    Public Function WithStrictMode(options As VisualBasicCompilationOptions) As VisualBasicCompilationOptions
+        Return options.WithFeatures(options.Features.Add("strict"))
+    End Function
+
+    <Extension()>
+    Public Function WithStrictMode(compilation As VisualBasicCompilation) As VisualBasicCompilation
+        Return compilation.WithOptions(compilation.Options.WithStrictMode())
+    End Function
+End Module

src/Compilers/VisualBasic/Portable/Binding/Binder_Expressions.vb

@@ -1551,11 +1551,10 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             ' an LValue. In this case, containingMember will be a LambdaSymbol rather than a symbol for
             ' constructor.
 
-            If Me.ContainingMember.ContainingSymbol Is field.ContainingSymbol Then
-                Return True
-            End If
-
-            Return False
+            ' We duplicate a bug in the native compiler for compatibility in non-strict mode
+            Return If(Me.Compilation.FeatureStrictEnabled,
+                Me.ContainingMember.ContainingSymbol Is field.ContainingSymbol,
+                Me.ContainingMember.ContainingSymbol.OriginalDefinition Is field.ContainingSymbol.OriginalDefinition)
         End Function
 
         ''' <summary>

src/Compilers/VisualBasic/Portable/Compilation/VisualBasicCompilation.vb

@@ -1820,6 +1820,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             Return New SyntaxTreeSemanticModel(Me, DirectCast(Me.SourceModule, SourceModuleSymbol), syntaxTree, ignoreAccessibility)
         End Function
 
+        Friend ReadOnly Property FeatureStrictEnabled As Boolean
+            Get
+                Return Me.Feature("strict") IsNot Nothing
+            End Get
+        End Property
+
 #End Region
 
 #Region "Diagnostics"

src/Compilers/VisualBasic/Test/Semantic/Semantics/FieldInitializerBindingTests.vb

@@ -1408,6 +1408,78 @@ BC30799: Field 'Clazz.b' has an invalid constant value.
 </errors>)
         End Sub
 
+        <Fact, WorkItem(1028, "https://github.com/dotnet/roslyn/issues/1028")>
+        Sub WriteOfReadonlySharedMemberOfAnotherInstantiation01()
+            Dim compilation = CompilationUtils.CreateCompilationWithMscorlib(
+   <compilation>
+       <file name="a.vb">
+Class Foo(Of T)
+    Shared Sub New()
+        Foo(Of Integer).X = 12
+        Foo(Of Integer).Y = 12
+        Foo(Of T).X = 12
+        Foo(Of T).Y = 12
+    End Sub
+
+    Public Shared ReadOnly X As Integer
+    Public Shared ReadOnly Property Y As Integer = 0
+End Class
+        </file>
+   </compilation>, TestOptions.ReleaseDll)
+
+            CompilationUtils.AssertTheseDiagnostics(compilation, <expected>
+BC30526: Property 'Y' is 'ReadOnly'.
+        Foo(Of Integer).Y = 12
+        ~~~~~~~~~~~~~~~~~~~~~~
+</expected>)
+
+            CompilationUtils.AssertTheseDiagnostics(compilation.WithStrictMode(), <expected>
+BC30064: 'ReadOnly' variable cannot be the target of an assignment.
+        Foo(Of Integer).X = 12
+        ~~~~~~~~~~~~~~~~~
+BC30526: Property 'Y' is 'ReadOnly'.
+        Foo(Of Integer).Y = 12
+        ~~~~~~~~~~~~~~~~~~~~~~
+</expected>)
+        End Sub
+
+        <Fact, WorkItem(1028, "https://github.com/dotnet/roslyn/issues/1028")>
+        Public Sub WriteOfReadonlySharedMemberOfAnotherInstantiation02()
+            CompileAndVerify(
+<compilation>
+    <file name="a.vb">
+Imports System
+
+Module M1
+    Sub Main()
+        Console.WriteLine(Foo(Of Long).X)
+        Console.WriteLine(Foo(Of Integer).X)
+        Console.WriteLine(Foo(Of String).X)
+        Console.WriteLine(Foo(Of Integer).X)
+    End Sub
+End Module
+
+Public Class Foo(Of T)
+    Shared Sub New()
+        Console.WriteLine("Initializing for {0}", GetType(T))
+        Foo(Of Integer).X = GetType(T).Name
+    End Sub
+
+    Public Shared ReadOnly X As String
+End Class
+    </file>
+</compilation>,
+verify:=False,
+expectedOutput:="Initializing for System.Int64
+Initializing for System.Int32
+
+Int64
+Initializing for System.String
+
+String
+")
+        End Sub
+
 #Region "Helpers"
         Private Shared Function CompileAndExtractTypeSymbol(sources As Xml.Linq.XElement, Optional typeName As String = "C") As SourceNamedTypeSymbol
             Dim compilation = CompilationUtils.CreateCompilationWithMscorlib(sources)