Implement IDkmClrFormatter2 and IDkmClrFullNameProvider

src/ExpressionEvaluator/CSharp/Source/ExpressionCompiler/project.json

 {
   "dependencies": {
-    "Microsoft.VisualStudio.Debugger.Engine": "14.3.25422"
+    "Microsoft.VisualStudio.Debugger.Engine": "15.0.25824-RC"
   },
   "frameworks": {
     "netstandard1.3": {

src/ExpressionEvaluator/CSharp/Source/ResultProvider/CSharpFormatter.Values.cs

@@ -98,30 +98,12 @@ internal override string GetArrayDisplayString(DkmClrAppDomain appDomain, Type l
             return pooled.ToStringAndFree();
         }
 
-        internal override string GetArrayIndexExpression(int[] indices)
+        internal override string GetArrayIndexExpression(string[] indices)
         {
-            Debug.Assert(indices != null);
-
-            var pooled = PooledStringBuilder.GetInstance();
-            var builder = pooled.Builder;
-
-            builder.Append('[');
-            bool any = false;
-            foreach (var index in indices)
-            {
-                if (any)
-                {
-                    builder.Append(", ");
-                }
-                builder.Append(index);
-                any = true;
-            }
-            builder.Append(']');
-
-            return pooled.ToStringAndFree();
+            return indices.ToCommaSeparatedString('[', ']');
         }
 
-        internal override string GetCastExpression(string argument, string type, bool parenthesizeArgument, bool parenthesizeEntireExpression)
+        internal override string GetCastExpression(string argument, string type, DkmClrCastExpressionOptions options)
         {
             Debug.Assert(!string.IsNullOrEmpty(argument));
             Debug.Assert(!string.IsNullOrEmpty(type));
@@ -129,15 +111,28 @@ internal override string GetCastExpression(string argument, string type, bool pa
             var pooled = PooledStringBuilder.GetInstance();
             var builder = pooled.Builder;
 
-            if (parenthesizeEntireExpression)
+            if ((options & DkmClrCastExpressionOptions.ParenthesizeEntireExpression) != 0)
             {
                 builder.Append('(');
             }
-
-            var castExpressionFormat = parenthesizeArgument ? "({0})({1})" : "({0}){1}";
-            builder.AppendFormat(castExpressionFormat, type, argument);
-
-            if (parenthesizeEntireExpression)
+            if ((options & DkmClrCastExpressionOptions.ParenthesizeArgument) != 0)
+            {
+                argument = $"({argument})";
+            }
+            if ((options & DkmClrCastExpressionOptions.ConditionalCast) != 0)
+            {
+                builder.Append(argument);
+                builder.Append(" as ");
+                builder.Append(type);
+            }
+            else
+            {
+                builder.Append('(');
+                builder.Append(type);
+                builder.Append(')');
+                builder.Append(argument);
+            }
+            if ((options & DkmClrCastExpressionOptions.ParenthesizeEntireExpression) != 0)
             {
                 builder.Append(')');
             }
@@ -147,25 +142,7 @@ internal override string GetCastExpression(string argument, string type, bool pa
 
         internal override string GetTupleExpression(string[] values)
         {
-            Debug.Assert(values != null);
-
-            var pooled = PooledStringBuilder.GetInstance();
-            var builder = pooled.Builder;
-
-            builder.Append('(');
-            bool any = false;
-            foreach (var value in values)
-            {
-                if (any)
-                {
-                    builder.Append(", ");
-                }
-                builder.Append(value);
-                any = true;
-            }
-            builder.Append(')');
-
-            return pooled.ToStringAndFree();
+            return values.ToCommaSeparatedString('(', ')');
         }
 
         internal override string GetNamesForFlagsEnumValue(ArrayBuilder<EnumField> fields, object value, ulong underlyingValue, ObjectDisplayOptions options, Type typeToDisplayOpt)
@@ -215,7 +192,7 @@ internal override string GetNameForEnumValue(ArrayBuilder<EnumField> fields, obj
             return null;
         }
 
-        internal override string GetObjectCreationExpression(string type, string arguments)
+        internal override string GetObjectCreationExpression(string type, string[] arguments)
         {
             Debug.Assert(!string.IsNullOrEmpty(type));
 
@@ -225,7 +202,7 @@ internal override string GetObjectCreationExpression(string type, string argumen
             builder.Append("new ");
             builder.Append(type);
             builder.Append('(');
-            builder.Append(arguments);
+            builder.AppendCommaSeparatedList(arguments);
             builder.Append(')');
 
             return pooled.ToStringAndFree();

src/ExpressionEvaluator/CSharp/Source/ResultProvider/CSharpFormatter.cs

@@ -10,7 +10,7 @@ namespace Microsoft.CodeAnalysis.CSharp.ExpressionEvaluator
     internal sealed partial class CSharpFormatter : Formatter
     {
         public CSharpFormatter()
-            : base(defaultFormat: "{{{0}}}", nullString: "null")
+            : base(defaultFormat: "{{{0}}}", nullString: "null", thisString: "this")
         {
         }
 

src/ExpressionEvaluator/CSharp/Source/ResultProvider/Portable/project.json

 {
   "dependencies": {
-    "Microsoft.VisualStudio.Debugger.Engine": "14.3.25422",
-    "Microsoft.VisualStudio.Debugger.Metadata": "14.3.25421"
+    "Microsoft.VisualStudio.Debugger.Engine": "15.0.25824-RC",
+    "Microsoft.VisualStudio.Debugger.Metadata": "15.0.25824-RC"
   },
   "frameworks": {
     ".NETPortable,Version=v4.5,Profile=Profile7": { }

src/ExpressionEvaluator/CSharp/Test/ExpressionCompiler/project.json

 {
   "dependencies": {
-    "Microsoft.VisualStudio.Debugger.Engine": "14.3.25422",
+    "Microsoft.VisualStudio.Debugger.Engine": "15.0.25824-RC",
     "Microsoft.DiaSymReader": "1.1.0",
     "xunit": "2.2.0-beta4-build3444",
     "xunit.runner.console": "2.2.0-beta4-build3444",

src/ExpressionEvaluator/CSharp/Test/ResultProvider/ArrayExpansionTests.cs

@@ -279,6 +279,40 @@ public void NonZeroLowerBounds()
                 EvalResult("[4, 6]", "6", "int", "arrayExpr[4, 6]"));
         }
 
+        [Fact]
+        public void Hexadecimal()
+        {
+            var value = CreateDkmClrValue(new[] { 10, 20, 30 });
+            var inspectionContext = CreateDkmInspectionContext(radix: 16);
+            var evalResult = FormatResult("o", value, inspectionContext: inspectionContext);
+            Verify(evalResult,
+                EvalResult("o", "{int[0x00000003]}", "int[]", "o", DkmEvaluationResultFlags.Expandable));
+            var children = GetChildren(evalResult, inspectionContext);
+            // Hex could be used for indices: [0x00000000], etc.
+            Verify(children,
+                EvalResult("[0]", "0x0000000a", "int", "o[0]"),
+                EvalResult("[1]", "0x00000014", "int", "o[1]"),
+                EvalResult("[2]", "0x0000001e", "int", "o[2]"));
+        }
+
+        [Fact]
+        public void HexadecimalNonZeroLowerBounds()
+        {
+            var array = (int[,])System.Array.CreateInstance(typeof(int), new[] { 2, 1 }, new[] { -3, 4 });
+            array[-3, 4] = 1;
+            array[-2, 4] = 2;
+            var value = CreateDkmClrValue(array);
+            var inspectionContext = CreateDkmInspectionContext(radix: 16);
+            var evalResult = FormatResult("a", value, inspectionContext: inspectionContext);
+            Verify(evalResult,
+                EvalResult("a", "{int[0xfffffffd..0xfffffffe, 0x00000004..0x00000004]}", "int[,]", "a", DkmEvaluationResultFlags.Expandable));
+            var children = GetChildren(evalResult, inspectionContext);
+            // Hex could be used for indices: [0xfffffffd, 0x00000004], etc.
+            Verify(children,
+                EvalResult("[-3, 4]", "0x00000001", "int", "a[-3, 4]"),
+                EvalResult("[-2, 4]", "0x00000002", "int", "a[-2, 4]"));
+        }
+
         /// <summary>
         /// Expansion should be lazy so that the IDE can
         /// reduce overhead by expanding a subset of rows.

src/ExpressionEvaluator/CSharp/Test/ResultProvider/CustomResultProviderTests.cs

@@ -210,17 +210,17 @@ string IDkmClrFullNameProvider.GetClrTypeName(DkmInspectionContext inspectionCon
                 throw new NotImplementedException();
             }
 
-            string IDkmClrFullNameProvider.GetClrArrayIndexExpression(DkmInspectionContext inspectionContext, int[] indices)
+            string IDkmClrFullNameProvider.GetClrArrayIndexExpression(DkmInspectionContext inspectionContext, string[] indices)
             {
                 throw new NotImplementedException();
             }
 
-            string IDkmClrFullNameProvider.GetClrCastExpression(DkmInspectionContext inspectionContext, string argument, DkmClrType type, DkmClrCustomTypeInfo customTypeInfo, bool parenthesizeArgument, bool parenthesizeEntireExpression)
+            string IDkmClrFullNameProvider.GetClrCastExpression(DkmInspectionContext inspectionContext, string argument, DkmClrType type, DkmClrCustomTypeInfo customTypeInfo, DkmClrCastExpressionOptions castExpressionOptions)
             {
                 throw new NotImplementedException();
             }
 
-            string IDkmClrFullNameProvider.GetClrObjectCreationExpression(DkmInspectionContext inspectionContext, DkmClrType type, DkmClrCustomTypeInfo customTypeInfo, string arguments)
+            string IDkmClrFullNameProvider.GetClrObjectCreationExpression(DkmInspectionContext inspectionContext, DkmClrType type, DkmClrCustomTypeInfo customTypeInfo, string[] arguments)
             {
                 throw new NotImplementedException();
             }
@@ -251,6 +251,16 @@ bool IDkmClrFullNameProvider.ClrExpressionMayRequireParentheses(DkmInspectionCon
             {
                 return ((IDkmClrFullNameProvider)_fallback).GetClrMemberName(inspectionContext, parentFullName, declaringType, declaringTypeInfo, memberName, memberAccessRequiresExplicitCast, memberIsStatic);
             }
+
+            string IDkmClrFullNameProvider.GetClrExpressionForNull(DkmInspectionContext inspectionContext)
+            {
+                throw new NotImplementedException();
+            }
+
+            string IDkmClrFullNameProvider.GetClrExpressionForThis(DkmInspectionContext inspectionContext)
+            {
+                throw new NotImplementedException();
+            }
         }
     }
 }

src/ExpressionEvaluator/CSharp/Test/ResultProvider/FullNameTests.cs

@@ -5,6 +5,7 @@
 using System.Linq;
 using Microsoft.CodeAnalysis.CSharp.Test.Utilities;
 using Microsoft.CodeAnalysis.ExpressionEvaluator;
+using Microsoft.VisualStudio.Debugger.ComponentInterfaces;
 using Microsoft.VisualStudio.Debugger.Clr;
 using Microsoft.VisualStudio.Debugger.Evaluation;
 using Roslyn.Test.Utilities;
@@ -14,6 +15,66 @@ namespace Microsoft.CodeAnalysis.CSharp.ExpressionEvaluator.UnitTests
 {
     public class FullNameTests : CSharpResultProviderTestBase
     {
+        [Fact]
+        public void Null()
+        {
+            IDkmClrFullNameProvider fullNameProvider = new CSharpFormatter();
+            var inspectionContext = CreateDkmInspectionContext();
+            Assert.Equal("null", fullNameProvider.GetClrExpressionForNull(inspectionContext));
+        }
+
+        [Fact]
+        public void This()
+        {
+            IDkmClrFullNameProvider fullNameProvider = new CSharpFormatter();
+            var inspectionContext = CreateDkmInspectionContext();
+            Assert.Equal("this", fullNameProvider.GetClrExpressionForThis(inspectionContext));
+        }
+
+        [Fact]
+        public void ArrayIndex()
+        {
+            IDkmClrFullNameProvider fullNameProvider = new CSharpFormatter();
+            var inspectionContext = CreateDkmInspectionContext();
+            Assert.Equal("[]", fullNameProvider.GetClrArrayIndexExpression(inspectionContext, new string[0]));
+            Assert.Equal("[]", fullNameProvider.GetClrArrayIndexExpression(inspectionContext, new[] { "" }));
+            Assert.Equal("[ ]", fullNameProvider.GetClrArrayIndexExpression(inspectionContext, new[] { " " }));
+            Assert.Equal("[1]", fullNameProvider.GetClrArrayIndexExpression(inspectionContext, new[] { "1" }));
+            Assert.Equal("[[], 2, 3]", fullNameProvider.GetClrArrayIndexExpression(inspectionContext, new[] { "[]", "2", "3" }));
+            Assert.Equal("[, , ]", fullNameProvider.GetClrArrayIndexExpression(inspectionContext, new[] { "", "", "" }));
+        }
+
+        [Fact]
+        public void Cast()
+        {
+            var source =
+@"class C
+{
+}";
+            var runtime = new DkmClrRuntimeInstance(ReflectionUtilities.GetMscorlib(GetAssembly(source)));
+            using (runtime.Load())
+            {
+                IDkmClrFullNameProvider fullNameProvider = new CSharpFormatter();
+                var inspectionContext = CreateDkmInspectionContext();
+                var type = runtime.GetType("C");
+
+                Assert.Equal("(C)o", fullNameProvider.GetClrCastExpression(inspectionContext, "o", type, null, DkmClrCastExpressionOptions.None));
+                Assert.Equal("o as C", fullNameProvider.GetClrCastExpression(inspectionContext, "o", type, null, DkmClrCastExpressionOptions.ConditionalCast));
+                Assert.Equal("(C)(o)", fullNameProvider.GetClrCastExpression(inspectionContext, "o", type, null, DkmClrCastExpressionOptions.ParenthesizeArgument));
+                Assert.Equal("(o) as C", fullNameProvider.GetClrCastExpression(inspectionContext, "o", type, null, DkmClrCastExpressionOptions.ParenthesizeArgument | DkmClrCastExpressionOptions.ConditionalCast));
+                Assert.Equal("((C)o)", fullNameProvider.GetClrCastExpression(inspectionContext, "o", type, null, DkmClrCastExpressionOptions.ParenthesizeEntireExpression));
+                Assert.Equal("(o as C)", fullNameProvider.GetClrCastExpression(inspectionContext, "o", type, null, DkmClrCastExpressionOptions.ParenthesizeEntireExpression | DkmClrCastExpressionOptions.ConditionalCast));
+                Assert.Equal("((C)(o))", fullNameProvider.GetClrCastExpression(inspectionContext, "o", type, null, DkmClrCastExpressionOptions.ParenthesizeEntireExpression | DkmClrCastExpressionOptions.ParenthesizeArgument));
+                Assert.Equal("((o) as C)", fullNameProvider.GetClrCastExpression(inspectionContext, "o", type, null, DkmClrCastExpressionOptions.ParenthesizeEntireExpression | DkmClrCastExpressionOptions.ParenthesizeArgument | DkmClrCastExpressionOptions.ConditionalCast));
+
+                // Some of the same tests with "..." as the expression ("..." is used
+                // by the debugger when the expression cannot be determined).
+                Assert.Equal("(C)...", fullNameProvider.GetClrCastExpression(inspectionContext, "...", type, null, DkmClrCastExpressionOptions.None));
+                Assert.Equal("... as C", fullNameProvider.GetClrCastExpression(inspectionContext, "...", type, null, DkmClrCastExpressionOptions.ConditionalCast));
+                Assert.Equal("(... as C)", fullNameProvider.GetClrCastExpression(inspectionContext, "...", type, null, DkmClrCastExpressionOptions.ParenthesizeEntireExpression | DkmClrCastExpressionOptions.ConditionalCast));
+            }
+        }
+
         [Fact]
         public void RootComment()
         {

src/ExpressionEvaluator/Core/Source/Concord/Concord.csproj

@@ -22,10 +22,10 @@
     <None Include="project.json" />
   </ItemGroup>
   <ItemGroup>
-    <Content Include="$(NuGetPackageRoot)\Microsoft.VisualStudio.Debugger.Engine\14.3.25422\lib\portable-net45+win8\Microsoft.VisualStudio.Debugger.Engine.dll">
+    <Content Include="$(NuGetPackageRoot)\Microsoft.VisualStudio.Debugger.Engine\15.0.25824-RC\lib\portable-net45+win8\Microsoft.VisualStudio.Debugger.Engine.dll">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
-    <Content Include="$(NuGetPackageRoot)\Microsoft.VisualStudio.Debugger.Metadata\14.3.25421\lib\portable-net45+win8\Microsoft.VisualStudio.Debugger.Metadata.dll">
+    <Content Include="$(NuGetPackageRoot)\Microsoft.VisualStudio.Debugger.Metadata\15.0.25824-RC\lib\portable-net45+win8\Microsoft.VisualStudio.Debugger.Metadata.dll">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
   </ItemGroup>

src/ExpressionEvaluator/Core/Source/Concord/project.json

 {  
   "dependencies": {
-    "Microsoft.VisualStudio.Debugger.Engine": "14.3.25422",
-    "Microsoft.VisualStudio.Debugger.Metadata": "14.3.25421"
+    "Microsoft.VisualStudio.Debugger.Engine": "15.0.25824-RC",
+    "Microsoft.VisualStudio.Debugger.Metadata": "15.0.25824-RC"
   },  
   "frameworks": {
     ".NETPortable,Version=v4.5,Profile=Profile7": { }

src/ExpressionEvaluator/Core/Source/ExpressionCompiler/DkmUtilities.cs

@@ -18,8 +18,6 @@ namespace Microsoft.CodeAnalysis.ExpressionEvaluator
 {
     internal static class DkmUtilities
     {
-        private static readonly Guid s_symUnmanagedReaderClassId = Guid.Parse("B4CE6286-2A6B-3712-A3B7-1EE1DAD467B5");
-
         internal unsafe delegate IntPtr GetMetadataBytesPtrFunction(AssemblyIdentity assemblyIdentity, out uint uSize);
 
         // Return the set of managed module instances from the AppDomain.
@@ -146,7 +144,14 @@ private unsafe static MetadataBlock GetMetadataBlock(IntPtr ptr, uint size)
         internal static object GetSymReader(this DkmClrModuleInstance clrModule)
         {
             var module = clrModule.Module; // Null if there are no symbols.
-            return (module == null) ? null : module.GetSymbolInterface(s_symUnmanagedReaderClassId);
+            if (module == null)
+            {
+                return null;
+            }
+            // Use DkmClrModuleInstance.GetSymUnmanagedReader()
+            // rather than DkmModule.GetSymbolInterface() since the
+            // latter does not handle .NET Native modules.
+            return clrModule.GetSymUnmanagedReader();
         }
 
         internal static DkmCompiledClrInspectionQuery ToQueryResult(

src/ExpressionEvaluator/Core/Source/ExpressionCompiler/project.json

 {
   "dependencies": {
-    "Microsoft.VisualStudio.Debugger.Engine": "14.3.25422",
+    "Microsoft.VisualStudio.Debugger.Engine": "15.0.25824-RC",
     "Microsoft.DiaSymReader": "1.1.0"
   },
   "frameworks": {

src/ExpressionEvaluator/Core/Source/FunctionResolver/project.json

@@ -3,7 +3,7 @@
     "Microsoft.NETCore.Portable.Compatibility": "1.0.1",
     "System.Collections.Immutable": "1.3.1",
     "System.Reflection.Metadata": "1.4.2",
-    "Microsoft.VisualStudio.Debugger.Engine": "14.3.25422",
+    "Microsoft.VisualStudio.Debugger.Engine": "15.0.25824-RC",
   },
   "frameworks": {
     "netstandard1.3": {

src/ExpressionEvaluator/Core/Source/ResultProvider/Expansion/ArrayExpansion.cs

@@ -2,6 +2,7 @@
 
 using System.Collections.ObjectModel;
 using System.Diagnostics;
+using Microsoft.VisualStudio.Debugger.Clr;
 using Microsoft.VisualStudio.Debugger.ComponentInterfaces;
 using Microsoft.VisualStudio.Debugger.Evaluation;
 using Microsoft.VisualStudio.Debugger.Evaluation.ClrCompilation;
@@ -74,7 +75,7 @@ private ArrayExpansion(TypeAndCustomInfo elementTypeAndInfo, ReadOnlyCollection<
         {
             var indices = GetIndices(index);
             var fullNameProvider = resultProvider.FullNameProvider;
-            var name = fullNameProvider.GetClrArrayIndexExpression(inspectionContext, indices);
+            var name = fullNameProvider.GetClrArrayIndexExpression(inspectionContext, GetIndicesAsStrings(indices));
             var element = value.GetArrayElement(indices, inspectionContext);
             var fullName = GetFullName(inspectionContext, parent, name, fullNameProvider);
             return resultProvider.CreateDataItem(
@@ -111,6 +112,17 @@ private int[] GetIndices(int index)
             return indices;
         }
 
+        private static string[] GetIndicesAsStrings(int[] indices)
+        {
+            var n = indices.Length;
+            var strings = new string[n];
+            for (int i = 0; i < n; i++)
+            {
+                strings[i] = indices[i].ToString();
+            }
+            return strings;
+        }
+
         private static ReadOnlyCollection<int> CalculateDivisors(ReadOnlyCollection<int> sizes)
         {
             var n = sizes.Count;
@@ -143,7 +155,12 @@ private static string GetFullName(DkmInspectionContext inspectionContext, EvalRe
             var parentRuntimeType = parent.Value.Type;
             if (!parent.DeclaredTypeAndInfo.Type.Equals(parentRuntimeType.GetLmrType()))
             {
-                parentFullName = fullNameProvider.GetClrCastExpression(inspectionContext, parentFullName, parentRuntimeType, customTypeInfo: null, parenthesizeArgument: false, parenthesizeEntireExpression: true);
+                parentFullName = fullNameProvider.GetClrCastExpression(
+                    inspectionContext,
+                    parentFullName,
+                    parentRuntimeType,
+                    customTypeInfo: null,
+                    castExpressionOptions: DkmClrCastExpressionOptions.ParenthesizeEntireExpression);
                 if (parentFullName == null)
                 {
                     return null; // Contains invalid identifier.

src/ExpressionEvaluator/Core/Source/ResultProvider/Expansion/DebuggerTypeProxyExpansion.cs

@@ -123,7 +123,11 @@ internal sealed class DebuggerTypeProxyExpansion : Expansion
                 string proxyMemberFullNamePrefix = null;
                 if (childFullNamePrefix != null)
                 {
-                    proxyMemberFullNamePrefix = resultProvider.FullNameProvider.GetClrObjectCreationExpression(inspectionContext, proxyTypeAndInfo.ClrType, proxyTypeAndInfo.Info, childFullNamePrefix);
+                    proxyMemberFullNamePrefix = resultProvider.FullNameProvider.GetClrObjectCreationExpression(
+                        inspectionContext,
+                        proxyTypeAndInfo.ClrType,
+                        proxyTypeAndInfo.Info,
+                        new[] { childFullNamePrefix });
                 }
                 _proxyItem = new EvalResult(
                     ExpansionKind.Default,

src/ExpressionEvaluator/Core/Source/ResultProvider/Expansion/DynamicViewExpansion.cs

@@ -91,7 +91,11 @@ private EvalResult CreateDynamicViewRow(DkmInspectionContext inspectionContext,
             var fullName = isRootExpression ? name : parent.ChildFullNamePrefix;
             var childFullNamePrefix = (fullName == null) ?
                 null :
-                fullNameProvider.GetClrObjectCreationExpression(inspectionContext, proxyTypeAndInfo.ClrType, proxyTypeAndInfo.Info, fullName);
+                fullNameProvider.GetClrObjectCreationExpression(
+                    inspectionContext,
+                    proxyTypeAndInfo.ClrType,
+                    proxyTypeAndInfo.Info,
+                    new[] { fullName });
             var formatSpecifiers = isRootExpression ? Formatter.NoFormatSpecifiers : parent.FormatSpecifiers;
             return new EvalResult(
                 ExpansionKind.DynamicView,

src/ExpressionEvaluator/Core/Source/ResultProvider/Expansion/ResultsViewExpansion.cs

@@ -225,7 +225,11 @@ private ResultsViewExpansion(DkmClrValue proxyValue, Expansion proxyMembers)
             var fullName = parent.ChildFullNamePrefix;
             var childFullNamePrefix = (fullName == null) ?
                 null :
-                fullNameProvider.GetClrObjectCreationExpression(inspectionContext, proxyTypeAndInfo.ClrType, proxyTypeAndInfo.Info, fullName);
+                fullNameProvider.GetClrObjectCreationExpression(
+                    inspectionContext,
+                    proxyTypeAndInfo.ClrType,
+                    proxyTypeAndInfo.Info,
+                    new[] { fullName });
             return new EvalResult(
                 ExpansionKind.ResultsView,
                 Resources.ResultsView,
@@ -259,7 +263,11 @@ private ResultsViewExpansion(DkmClrValue proxyValue, Expansion proxyMembers)
             {
                 formatSpecifiers = Formatter.AddFormatSpecifier(formatSpecifiers, ResultsFormatSpecifier);
             }
-            var childFullNamePrefix = fullNameProvider.GetClrObjectCreationExpression(inspectionContext, _proxyValue.Type, customTypeInfo: null, arguments: fullName);
+            var childFullNamePrefix = fullNameProvider.GetClrObjectCreationExpression(
+                inspectionContext,
+                _proxyValue.Type,
+                customTypeInfo: null,
+                arguments: new[] { fullName });
             return new EvalResult(
                 ExpansionKind.Default,
                 name,

src/ExpressionEvaluator/Core/Source/ResultProvider/Expansion/TupleExpansion.cs

@@ -99,7 +99,12 @@ private TupleExpansion(TypeAndCustomInfo typeAndInfo, int cardinality, bool useR
                 var parentRuntimeType = parent.Value.Type;
                 if (!parent.DeclaredTypeAndInfo.Type.Equals(parentRuntimeType.GetLmrType()))
                 {
-                    parentFullName = fullNameProvider.GetClrCastExpression(inspectionContext, parentFullName, parentRuntimeType, customTypeInfo: null, parenthesizeArgument: false, parenthesizeEntireExpression: true);
+                    parentFullName = fullNameProvider.GetClrCastExpression(
+                        inspectionContext,
+                        parentFullName,
+                        parentRuntimeType,
+                        customTypeInfo: null,
+                        castExpressionOptions: DkmClrCastExpressionOptions.ParenthesizeEntireExpression);
                 }
             }
 
@@ -192,11 +197,11 @@ private TupleExpansion(TypeAndCustomInfo typeAndInfo, int cardinality, bool useR
                 fullNameProvider.GetClrMemberName(
                     inspectionContext,
                     parentFullName,
-                    declaringType: field.DeclaringTypeAndInfo.ClrType,
-                    declaringTypeInfo: null,
+                    clrType: field.DeclaringTypeAndInfo.ClrType,
+                    customTypeInfo: null,
                     memberName: fieldName,
-                    memberAccessRequiresExplicitCast: false,
-                    memberIsStatic: false);
+                    requiresExplicitCast: false,
+                    isStatic: false);
             return value.GetFieldValue(fieldName, inspectionContext);
         }
 

src/ExpressionEvaluator/Core/Source/ResultProvider/Formatter.Values.cs

@@ -409,15 +409,15 @@ private static string IncludeObjectId(DkmClrValue value, string valueStr, GetVal
 
         internal abstract string GetArrayDisplayString(DkmClrAppDomain appDomain, Type lmrType, ReadOnlyCollection<int> sizes, ReadOnlyCollection<int> lowerBounds, ObjectDisplayOptions options);
 
-        internal abstract string GetArrayIndexExpression(int[] indices);
+        internal abstract string GetArrayIndexExpression(string[] indices);
 
-        internal abstract string GetCastExpression(string argument, string type, bool parenthesizeArgument, bool parenthesizeEntireExpression);
+        internal abstract string GetCastExpression(string argument, string type, DkmClrCastExpressionOptions options);
 
         internal abstract string GetNamesForFlagsEnumValue(ArrayBuilder<EnumField> fields, object value, ulong underlyingValue, ObjectDisplayOptions options, Type typeToDisplayOpt);
 
         internal abstract string GetNameForEnumValue(ArrayBuilder<EnumField> fields, object value, ulong underlyingValue, ObjectDisplayOptions options, Type typeToDisplayOpt);
 
-        internal abstract string GetObjectCreationExpression(string type, string arguments);
+        internal abstract string GetObjectCreationExpression(string type, string[] arguments);
 
         internal abstract string GetTupleExpression(string[] values);
 

src/ExpressionEvaluator/Core/Source/ResultProvider/Formatter.cs

@@ -21,11 +21,13 @@ internal abstract partial class Formatter : IDkmClrFormatter, IDkmClrFormatter2,
     {
         private readonly string _defaultFormat;
         private readonly string _nullString;
+        private readonly string _thisString;
 
-        internal Formatter(string defaultFormat, string nullString)
+        internal Formatter(string defaultFormat, string nullString, string thisString)
         {
             _defaultFormat = defaultFormat;
             _nullString = nullString;
+            _thisString = thisString;
         }
 
         string IDkmClrFormatter.GetValueString(DkmClrValue value, DkmInspectionContext inspectionContext, ReadOnlyCollection<string> formatSpecifiers)
@@ -71,12 +73,12 @@ string IDkmClrFullNameProvider.GetClrTypeName(DkmInspectionContext inspectionCon
             return sawInvalidIdentifier ? null : name;
         }
 
-        string IDkmClrFullNameProvider.GetClrArrayIndexExpression(DkmInspectionContext inspectionContext, int[] indices)
+        string IDkmClrFullNameProvider.GetClrArrayIndexExpression(DkmInspectionContext inspectionContext, string[] indices)
         {
             return GetArrayIndexExpression(indices);
         }
 
-        string IDkmClrFullNameProvider.GetClrCastExpression(DkmInspectionContext inspectionContext, string argument, DkmClrType type, DkmClrCustomTypeInfo customTypeInfo, bool parenthesizeArgument, bool parenthesizeEntireExpression)
+        string IDkmClrFullNameProvider.GetClrCastExpression(DkmInspectionContext inspectionContext, string argument, DkmClrType type, DkmClrCustomTypeInfo customTypeInfo, DkmClrCastExpressionOptions castExpressionOptions)
         {
             bool sawInvalidIdentifier;
             var name = GetTypeName(new TypeAndCustomInfo(type, customTypeInfo), escapeKeywordIdentifiers: true, sawInvalidIdentifier: out sawInvalidIdentifier);
@@ -84,10 +86,10 @@ string IDkmClrFullNameProvider.GetClrCastExpression(DkmInspectionContext inspect
             {
                 return null;
             }
-            return GetCastExpression(argument, name, parenthesizeArgument, parenthesizeEntireExpression);
+            return GetCastExpression(argument, name, castExpressionOptions);
         }
 
-        string IDkmClrFullNameProvider.GetClrObjectCreationExpression(DkmInspectionContext inspectionContext, DkmClrType type, DkmClrCustomTypeInfo customTypeInfo, string arguments)
+        string IDkmClrFullNameProvider.GetClrObjectCreationExpression(DkmInspectionContext inspectionContext, DkmClrType type, DkmClrCustomTypeInfo customTypeInfo, string[] arguments)
         {
             bool sawInvalidIdentifier;
             var name = GetTypeName(new TypeAndCustomInfo(type, customTypeInfo), escapeKeywordIdentifiers: true, sawInvalidIdentifier: out sawInvalidIdentifier);
@@ -146,11 +148,7 @@ bool IDkmClrFullNameProvider.ClrExpressionMayRequireParentheses(DkmInspectionCon
                 {
                     return null; // FullName wouldn't be parseable.
                 }
-                qualifier = GetCastExpression(
-                    parentFullName,
-                    typeName,
-                    parenthesizeArgument: false,
-                    parenthesizeEntireExpression: true);
+                qualifier = GetCastExpression(parentFullName, typeName, DkmClrCastExpressionOptions.ParenthesizeEntireExpression);
             }
             else
             {
@@ -159,6 +157,16 @@ bool IDkmClrFullNameProvider.ClrExpressionMayRequireParentheses(DkmInspectionCon
             return $"{qualifier}.{memberName}";
         }
 
+        string IDkmClrFullNameProvider.GetClrExpressionForNull(DkmInspectionContext inspectionContext)
+        {
+            return _nullString;
+        }
+
+        string IDkmClrFullNameProvider.GetClrExpressionForThis(DkmInspectionContext inspectionContext)
+        {
+            return _thisString;
+        }
+
         // CONSIDER: If the number or complexity of the "language-specific syntax helpers" grows (or if
         // we make this a public API, it would be good to consider abstracting them into a separate object
         // that can be passed to the ResultProvider on construction (a "LanguageSyntax" service of sorts).

src/ExpressionEvaluator/Core/Source/ResultProvider/Helpers/ValueHelpers.cs

 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+using Microsoft.CodeAnalysis.Collections;
 using Microsoft.VisualStudio.Debugger.Evaluation;
 using Microsoft.VisualStudio.Debugger.Evaluation.ClrCompilation;
 using System.Diagnostics;
+using System.Text;
 
 namespace Microsoft.CodeAnalysis.ExpressionEvaluator
 {
@@ -43,5 +45,33 @@ internal static string Parenthesize(this string expr)
         {
             return $"({expr})";
         }
+
+        internal static string ToCommaSeparatedString(this string[] values, char openParen, char closeParen)
+        {
+            Debug.Assert(values != null);
+
+            var pooled = PooledStringBuilder.GetInstance();
+            var builder = pooled.Builder;
+
+            builder.Append(openParen);
+            builder.AppendCommaSeparatedList(values);
+            builder.Append(closeParen);
+
+            return pooled.ToStringAndFree();
+        }
+
+        internal static void AppendCommaSeparatedList(this StringBuilder builder, string[] values)
+        {
+            bool any = false;
+            foreach (var value in values)
+            {
+                if (any)
+                {
+                    builder.Append(", ");
+                }
+                builder.Append(value);
+                any = true;
+            }
+        }
     }
 }

src/ExpressionEvaluator/Core/Source/ResultProvider/IDkmClrFullNameProvider.cs

-// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
-
-using System.Collections.ObjectModel;
-using Microsoft.VisualStudio.Debugger.Clr;
-using Microsoft.VisualStudio.Debugger.Evaluation;
-using Microsoft.VisualStudio.Debugger.Evaluation.ClrCompilation;
-
-namespace Microsoft.VisualStudio.Debugger.ComponentInterfaces
-{
-    internal interface IDkmClrFullNameProvider
-    {
-        /// <summary>
-        /// Return the type name in a form valid in the language (e.g.: escaping keywords)
-        /// or null if the name cannot be represented as valid syntax.
-        /// </summary>
-        string GetClrTypeName(DkmInspectionContext inspectionContext, DkmClrType type, DkmClrCustomTypeInfo customTypeInfo);
-
-        /// <summary>
-        /// Return an array index expression. Should not return null.
-        /// </summary>
-        string GetClrArrayIndexExpression(DkmInspectionContext inspectionContext, int[] indices);
-
-        /// <summary>
-        /// Return a cast expression or null if the type name would be invalid syntax.
-        /// </summary>
-        string GetClrCastExpression(DkmInspectionContext inspectionContext, string argument, DkmClrType type, DkmClrCustomTypeInfo customTypeInfo, bool parenthesizeArgument, bool parenthesizeEntireExpression);
-
-        /// <summary>
-        /// Return an object creation expression or null if the type name would be invalid syntax.
-        /// </summary>
-        string GetClrObjectCreationExpression(DkmInspectionContext inspectionContext, DkmClrType type, DkmClrCustomTypeInfo customTypeInfo, string arguments);
-
-        /// <summary>
-        /// Return the identifier in a form valid in the language (e.g.: escaping keywords)
-        /// or null if the identifier cannot be represented as a valid identifier.
-        /// </summary>
-        string GetClrValidIdentifier(DkmInspectionContext inspectionContext, string identifier);
-
-        /// <summary>
-        /// Return a member access expression or null if the expression cannot be
-        /// represented as valid syntax.
-        /// </summary>
-        string GetClrMemberName(
-            DkmInspectionContext inspectionContext,
-            string parentFullName,
-            DkmClrType declaringType,
-            DkmClrCustomTypeInfo declaringTypeInfo,
-            string memberName,
-            bool memberAccessRequiresExplicitCast,
-            bool memberIsStatic);
-
-        /// <summary>
-        /// Return true if the expression may require parentheses when used
-        /// as a sub-expression in the language.
-        /// </summary>
-        bool ClrExpressionMayRequireParentheses(DkmInspectionContext inspectionContext, string expression);
-
-        /// <summary>
-        /// Split the string into the expression and format specifier parts.
-        /// Returns the expression without format specifiers.
-        /// </summary>
-        string GetClrExpressionAndFormatSpecifiers(DkmInspectionContext inspectionContext, string expression, out ReadOnlyCollection<string> formatSpecifiers);
-    }
-}

src/ExpressionEvaluator/Core/Source/ResultProvider/NetFX20/project.json

 {
   "dependencies": {
     "Microsoft.NetFX20": "1.0.3",
-    "Microsoft.VisualStudio.Debugger.Engine": "14.3.25422",
-    "Microsoft.VisualStudio.Debugger.Metadata": "14.3.25421"
+    "Microsoft.VisualStudio.Debugger.Engine": "15.0.25824-RC",
+    "Microsoft.VisualStudio.Debugger.Metadata": "15.0.25824-RC"
   },
   "frameworks": {
     "net20": { }

src/ExpressionEvaluator/Core/Source/ResultProvider/Portable/project.json

 {
   "dependencies": {
-    "Microsoft.VisualStudio.Debugger.Engine": "14.3.25422",
-    "Microsoft.VisualStudio.Debugger.Metadata": "14.3.25421"
+    "Microsoft.VisualStudio.Debugger.Engine": "15.0.25824-RC",
+    "Microsoft.VisualStudio.Debugger.Metadata": "15.0.25824-RC"
   },
   "frameworks": {
     ".NETPortable,Version=v4.5,Profile=Profile7": { }

src/ExpressionEvaluator/Core/Source/ResultProvider/ResultProvider.projitems

@@ -19,8 +19,6 @@
     <Compile Include="$(MSBuildThisFileDirectory)Helpers\TypeWalker.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Helpers\AttributeHelpers.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Helpers\CustomTypeInfoTypeArgumentMap.cs" />
-    <Compile Include="$(MSBuildThisFileDirectory)IDkmClrFormatter2.cs" />
-    <Compile Include="$(MSBuildThisFileDirectory)IDkmClrFullNameProvider.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)ResultProvider.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Expansion\AggregateExpansion.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Expansion\ArrayExpansion.cs" />

src/ExpressionEvaluator/Core/Test/ExpressionCompiler/project.json

 {
   "dependencies": {
-    "Microsoft.VisualStudio.Debugger.Engine": "14.3.25422",
+    "Microsoft.VisualStudio.Debugger.Engine": "15.0.25824-RC",
     "Microsoft.DiaSymReader": "1.1.0",
     "xunit": "2.2.0-beta4-build3444",
     "xunit.runner.console": "2.2.0-beta4-build3444",

src/ExpressionEvaluator/Core/Test/FunctionResolver/project.json

 {
   "dependencies": {
-    "Microsoft.VisualStudio.Debugger.Engine": "14.3.25422",
+    "Microsoft.VisualStudio.Debugger.Engine": "15.0.25824-RC",
     "xunit": "2.2.0-beta4-build3444",
     "xunit.runner.console": "2.2.0-beta4-build3444",
     "xunit.runner.visualstudio": "2.2.0-beta4-build1194"

src/ExpressionEvaluator/Core/Test/ResultProvider/Debugger/Engine/DkmClrCastExpressionOptions.cs

+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+#region Assembly Microsoft.VisualStudio.Debugger.Engine, Version=1.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
+// References\Debugger\v2.0\Microsoft.VisualStudio.Debugger.Engine.dll
+#endregion
+
+namespace Microsoft.VisualStudio.Debugger.Clr
+{
+    public enum DkmClrCastExpressionOptions
+    {
+        None = 0,
+        ConditionalCast = 1,
+        ParenthesizeArgument = 2,
+        ParenthesizeEntireExpression = 4
+    }
+}

src/ExpressionEvaluator/Core/Source/ResultProvider/IDkmClrFormatter2.cs → src/ExpressionEvaluator/Core/Test/ResultProvider/Debugger/Engine/IDkmClrFormatter2.cs

 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+#region Assembly Microsoft.VisualStudio.Debugger.Engine, Version=1.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
+// References\Debugger\v2.0\Microsoft.VisualStudio.Debugger.Engine.dll
+#endregion
+
 using System.Collections.ObjectModel;
 using Microsoft.VisualStudio.Debugger.Evaluation;
 using Microsoft.VisualStudio.Debugger.Evaluation.ClrCompilation;
 
 namespace Microsoft.VisualStudio.Debugger.ComponentInterfaces
 {
-    internal interface IDkmClrFormatter2
+    public interface IDkmClrFormatter2
     {
         string GetValueString(DkmClrValue clrValue, DkmClrCustomTypeInfo customTypeInfo, DkmInspectionContext inspectionContext, ReadOnlyCollection<string> formatSpecifiers);
         string GetEditableValueString(DkmClrValue value, DkmInspectionContext inspectionContext, DkmClrCustomTypeInfo customTypeInfo);

src/ExpressionEvaluator/Core/Test/ResultProvider/Debugger/Engine/IDkmClrFullNameProvider.cs

+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+#region Assembly Microsoft.VisualStudio.Debugger.Engine, Version=1.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
+// References\Debugger\v2.0\Microsoft.VisualStudio.Debugger.Engine.dll
+#endregion
+
+using System.Collections.ObjectModel;
+using Microsoft.VisualStudio.Debugger.Clr;
+using Microsoft.VisualStudio.Debugger.Evaluation;
+using Microsoft.VisualStudio.Debugger.Evaluation.ClrCompilation;
+
+namespace Microsoft.VisualStudio.Debugger.ComponentInterfaces
+{
+    public interface IDkmClrFullNameProvider
+    {
+        string GetClrTypeName(
+            DkmInspectionContext inspectionContext,
+            DkmClrType clrType,
+            DkmClrCustomTypeInfo customTypeInfo);
+
+        string GetClrArrayIndexExpression(
+            DkmInspectionContext inspectionContext,
+            string[] indices);
+
+        string GetClrCastExpression(
+            DkmInspectionContext inspectionContext,
+            string argument,
+            DkmClrType clrType,
+            DkmClrCustomTypeInfo customTypeInfo,
+            DkmClrCastExpressionOptions castExpressionOptions);
+
+        string GetClrObjectCreationExpression(
+            DkmInspectionContext inspectionContext,
+            DkmClrType clrType,
+            DkmClrCustomTypeInfo customTypeInfo,
+            string[] arguments);
+
+        string GetClrValidIdentifier(
+            DkmInspectionContext inspectionContext,
+            string identifier);
+
+        string GetClrMemberName(
+            DkmInspectionContext inspectionContext,
+            string parentFullName,
+            DkmClrType clrType,
+            DkmClrCustomTypeInfo customTypeInfo,
+            string memberName,
+            bool requiresExplicitCast,
+            bool isStatic);
+
+        bool ClrExpressionMayRequireParentheses(
+            DkmInspectionContext inspectionContext,
+            string expression);
+
+        string GetClrExpressionAndFormatSpecifiers(
+            DkmInspectionContext inspectionContext,
+            string expression,
+            out ReadOnlyCollection<string> formatSpecifiers);
+
+        string GetClrExpressionForNull(DkmInspectionContext inspectionContext);
+
+        string GetClrExpressionForThis(DkmInspectionContext inspectionContext);
+    }
+}

src/ExpressionEvaluator/Core/Test/ResultProvider/ResultProviderTestUtilities.csproj

@@ -92,6 +92,7 @@
     </Compile>
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Debugger\Engine\DkmClrCastExpressionOptions.cs" />
     <Compile Include="Debugger\Engine\DkmClrCustomTypeInfo.cs" />
     <Compile Include="Debugger\Engine\DkmCompilerId.cs" />
     <Compile Include="Debugger\Engine\DkmContinueCorruptingException.cs" />
@@ -137,6 +138,8 @@
     <Compile Include="Debugger\Engine\DkmVendorId.cs" />
     <Compile Include="Debugger\Engine\DkmWorkList.cs" />
     <Compile Include="Debugger\Engine\IDkmClrFormatter.cs" />
+    <Compile Include="Debugger\Engine\IDkmClrFormatter2.cs" />
+    <Compile Include="Debugger\Engine\IDkmClrFullNameProvider.cs" />
     <Compile Include="Debugger\Engine\IDkmClrResultProvider.cs" />
     <Compile Include="Debugger\MemberInfo\AssemblyImpl.cs" />
     <Compile Include="Debugger\MemberInfo\ConstructorInfoImpl.cs" />

src/ExpressionEvaluator/Core/Test/ResultProvider/project.json

 {
   "dependencies": {
     "System.Collections.Immutable": "1.3.1",
-    "Microsoft.VisualStudio.Debugger.Metadata": "14.3.25421",
+    "Microsoft.VisualStudio.Debugger.Metadata": "15.0.25824-RC",
     "xunit": "2.2.0-beta4-build3444",
     "xunit.runner.console": "2.2.0-beta4-build3444",
     "xunit.runner.visualstudio": "2.2.0-beta4-build1194"

src/ExpressionEvaluator/VisualBasic/Source/ExpressionCompiler/project.json

 {
   "dependencies": {
-    "Microsoft.VisualStudio.Debugger.Engine": "14.3.25422"
+    "Microsoft.VisualStudio.Debugger.Engine": "15.0.25824-RC"
   },
   "frameworks": {
     "netstandard1.3": {

src/ExpressionEvaluator/VisualBasic/Source/ResultProvider/Portable/project.json

 {
   "dependencies": {
-    "Microsoft.VisualStudio.Debugger.Engine": "14.3.25422",
-    "Microsoft.VisualStudio.Debugger.Metadata": "14.3.25421"
+    "Microsoft.VisualStudio.Debugger.Engine": "15.0.25824-RC",
+    "Microsoft.VisualStudio.Debugger.Metadata": "15.0.25824-RC"
   },
   "frameworks": {
     ".NETPortable,Version=v4.5,Profile=Profile7": { }

src/ExpressionEvaluator/VisualBasic/Source/ResultProvider/VisualBasicFormatter.Values.vb

@@ -3,6 +3,7 @@
 Imports System.Collections.ObjectModel
 Imports System.Text
 Imports Microsoft.CodeAnalysis.Collections
+Imports Microsoft.CodeAnalysis.ExpressionEvaluator
 Imports Microsoft.VisualStudio.Debugger.Clr
 Imports Roslyn.Utilities
 Imports Type = Microsoft.VisualStudio.Debugger.Metadata.Type
@@ -64,34 +65,27 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.ExpressionEvaluator
             Return pooled.ToStringAndFree()
         End Function
 
-        Friend Overrides Function GetArrayIndexExpression(indices() As Integer) As String
-            Debug.Assert(indices IsNot Nothing)
-
-            Dim pooled = PooledStringBuilder.GetInstance()
-            Dim builder = pooled.Builder
-
-            builder.Append("("c)
-            Dim any As Boolean = False
-            For Each index In indices
-                If any Then
-                    builder.Append(", ")
-                End If
-                builder.Append(index)
-                any = True
-            Next
-            builder.Append(")"c)
-
-            Return pooled.ToStringAndFree()
+        Friend Overrides Function GetArrayIndexExpression(indices() As String) As String
+            Return indices.ToCommaSeparatedString("("c, ")"c)
         End Function
 
-        Friend Overrides Function GetCastExpression(argument As String, type As String, parenthesizeArgument As Boolean, parenthesizeEntireExpression As Boolean) As String
+        Friend Overrides Function GetCastExpression(argument As String, type As String, options As DkmClrCastExpressionOptions) As String
             Debug.Assert(Not String.IsNullOrEmpty(argument))
             Debug.Assert(Not String.IsNullOrEmpty(type))
 
             Dim pooled = PooledStringBuilder.GetInstance()
             Dim builder = pooled.Builder
 
-            builder.Append("DirectCast(")
+            If (options And DkmClrCastExpressionOptions.ParenthesizeArgument) <> 0 Then
+                argument = $"({argument})"
+            End If
+
+            If (options And DkmClrCastExpressionOptions.ConditionalCast) <> 0 Then
+                builder.Append("TryCast(")
+            Else
+                builder.Append("DirectCast(")
+            End If
+
             builder.Append(argument)
             builder.Append(", ")
             builder.Append(type)
@@ -101,23 +95,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.ExpressionEvaluator
         End Function
 
         Friend Overrides Function GetTupleExpression(values() As String) As String
-            Debug.Assert(values IsNot Nothing)
-
-            Dim pooled = PooledStringBuilder.GetInstance()
-            Dim builder = pooled.Builder
-
-            builder.Append("("c)
-            Dim any As Boolean = False
-            For Each value In values
-                If any Then
-                    builder.Append(", ")
-                End If
-                builder.Append(value)
-                any = True
-            Next
-            builder.Append(")"c)
-
-            Return pooled.ToStringAndFree()
+            Return values.ToCommaSeparatedString("("c, ")"c)
         End Function
 
         Friend Overrides Function GetNamesForFlagsEnumValue(fields As ArrayBuilder(Of EnumField), value As Object, underlyingValue As ULong, options As ObjectDisplayOptions, typeToDisplayOpt As Type) As String
@@ -167,7 +145,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.ExpressionEvaluator
             Return Nothing
         End Function
 
-        Friend Overrides Function GetObjectCreationExpression(type As String, arguments As String) As String
+        Friend Overrides Function GetObjectCreationExpression(type As String, arguments As String()) As String
             Debug.Assert(Not String.IsNullOrEmpty(type))
 
             Dim pooled = PooledStringBuilder.GetInstance()
@@ -176,7 +154,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.ExpressionEvaluator
             builder.Append("New ")
             builder.Append(type)
             builder.Append("("c)
-            builder.Append(arguments)
+            builder.AppendCommaSeparatedList(arguments)
             builder.Append(")"c)
 
             Return pooled.ToStringAndFree()

src/ExpressionEvaluator/VisualBasic/Source/ResultProvider/VisualBasicFormatter.vb

@@ -20,7 +20,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.ExpressionEvaluator
         Friend Shared ReadOnly Instance As VisualBasicFormatter = New VisualBasicFormatter()
 
         Public Sub New()
-            MyBase.New(defaultFormat:="{{{0}}}", nullString:="Nothing")
+            MyBase.New(defaultFormat:="{{{0}}}", nullString:="Nothing", thisString:="Me")
         End Sub
 
         Friend Overrides Function IsValidIdentifier(name As String) As Boolean

src/ExpressionEvaluator/VisualBasic/Test/ExpressionCompiler/project.json

 {
   "dependencies": {
-    "Microsoft.VisualStudio.Debugger.Engine": "14.3.25422",
+    "Microsoft.VisualStudio.Debugger.Engine": "15.0.25824-RC",
     "Microsoft.DiaSymReader": "1.1.0",
     "xunit": "2.2.0-beta4-build3444",
     "xunit.runner.console": "2.2.0-beta4-build3444",

src/ExpressionEvaluator/VisualBasic/Test/ResultProvider/FullNameTests.vb

@@ -3,6 +3,8 @@
 Imports System.Collections.Immutable
 Imports Microsoft.CodeAnalysis.ExpressionEvaluator
 Imports Microsoft.CodeAnalysis.VisualBasic.UnitTests
+Imports Microsoft.VisualStudio.Debugger.Clr
+Imports Microsoft.VisualStudio.Debugger.ComponentInterfaces
 Imports Microsoft.VisualStudio.Debugger.Evaluation
 Imports Roslyn.Test.Utilities
 Imports Xunit
@@ -11,6 +13,60 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.ExpressionEvaluator.UnitTests
 
     Public Class FullNameTests : Inherits VisualBasicResultProviderTestBase
 
+        <Fact>
+        Public Sub Null()
+            Dim fullNameProvider As IDkmClrFullNameProvider = New VisualBasicFormatter()
+            Dim inspectionContext = CreateDkmInspectionContext()
+            Assert.Equal("Nothing", fullNameProvider.GetClrExpressionForNull(inspectionContext))
+        End Sub
+
+        <Fact>
+        Public Sub This()
+            Dim fullNameProvider As IDkmClrFullNameProvider = New VisualBasicFormatter()
+            Dim inspectionContext = CreateDkmInspectionContext()
+            Assert.Equal("Me", fullNameProvider.GetClrExpressionForThis(inspectionContext))
+        End Sub
+
+        <Fact>
+        Public Sub ArrayIndex()
+            Dim fullNameProvider As IDkmClrFullNameProvider = New VisualBasicFormatter()
+            Dim inspectionContext = CreateDkmInspectionContext()
+            Assert.Equal("()", fullNameProvider.GetClrArrayIndexExpression(inspectionContext, {}))
+            Assert.Equal("()", fullNameProvider.GetClrArrayIndexExpression(inspectionContext, {""}))
+            Assert.Equal("( )", fullNameProvider.GetClrArrayIndexExpression(inspectionContext, {" "}))
+            Assert.Equal("(1)", fullNameProvider.GetClrArrayIndexExpression(inspectionContext, {"1"}))
+            Assert.Equal("((), 2, 3)", fullNameProvider.GetClrArrayIndexExpression(inspectionContext, {"()", "2", "3"}))
+            Assert.Equal("(, , )", fullNameProvider.GetClrArrayIndexExpression(inspectionContext, {"", "", ""}))
+        End Sub
+
+        <Fact>
+        Public Sub Cast()
+            Const source =
+"Class C
+End Class"
+            Dim runtime = New DkmClrRuntimeInstance(ReflectionUtilities.GetMscorlibAndSystemCore(GetAssembly(source)))
+            Using runtime.Load()
+                Dim fullNameProvider As IDkmClrFullNameProvider = New VisualBasicFormatter()
+                Dim inspectionContext = CreateDkmInspectionContext()
+                Dim type = runtime.GetType("C")
+
+                Assert.Equal("DirectCast(o, C)", fullNameProvider.GetClrCastExpression(inspectionContext, "o", type, Nothing, DkmClrCastExpressionOptions.None))
+                Assert.Equal("TryCast(o, C)", fullNameProvider.GetClrCastExpression(inspectionContext, "o", type, Nothing, DkmClrCastExpressionOptions.ConditionalCast))
+                Assert.Equal("DirectCast((o), C)", fullNameProvider.GetClrCastExpression(inspectionContext, "o", type, Nothing, DkmClrCastExpressionOptions.ParenthesizeArgument))
+                Assert.Equal("TryCast((o), C)", fullNameProvider.GetClrCastExpression(inspectionContext, "o", type, Nothing, DkmClrCastExpressionOptions.ParenthesizeArgument Or DkmClrCastExpressionOptions.ConditionalCast))
+                Assert.Equal("DirectCast(o, C)", fullNameProvider.GetClrCastExpression(inspectionContext, "o", type, Nothing, DkmClrCastExpressionOptions.ParenthesizeEntireExpression))
+                Assert.Equal("TryCast(o, C)", fullNameProvider.GetClrCastExpression(inspectionContext, "o", type, Nothing, DkmClrCastExpressionOptions.ParenthesizeEntireExpression Or DkmClrCastExpressionOptions.ConditionalCast))
+                Assert.Equal("DirectCast((o), C)", fullNameProvider.GetClrCastExpression(inspectionContext, "o", type, Nothing, DkmClrCastExpressionOptions.ParenthesizeEntireExpression Or DkmClrCastExpressionOptions.ParenthesizeArgument))
+                Assert.Equal("TryCast((o), C)", fullNameProvider.GetClrCastExpression(inspectionContext, "o", type, Nothing, DkmClrCastExpressionOptions.ParenthesizeEntireExpression Or DkmClrCastExpressionOptions.ParenthesizeArgument Or DkmClrCastExpressionOptions.ConditionalCast))
+
+                ' Some of the same tests with "..." as the expression ("..." is used
+                ' by the debugger when the expression cannot be determined).
+                Assert.Equal("DirectCast(..., C)", fullNameProvider.GetClrCastExpression(inspectionContext, "...", type, Nothing, DkmClrCastExpressionOptions.None))
+                Assert.Equal("TryCast(..., C)", fullNameProvider.GetClrCastExpression(inspectionContext, "...", type, Nothing, DkmClrCastExpressionOptions.ConditionalCast))
+                Assert.Equal("TryCast(..., C)", fullNameProvider.GetClrCastExpression(inspectionContext, "...", type, Nothing, DkmClrCastExpressionOptions.ParenthesizeEntireExpression Or DkmClrCastExpressionOptions.ConditionalCast))
+            End Using
+        End Sub
+
         <Fact>
         Public Sub RootComment()
             Dim source = "