VB: Define special error type symbol to represent a pointer type, enables...

VB: Define special error type symbol to represent a pointer type, enables accurate comparison of signatures of methods imported from metadata.
***NO_CI***
 (changeset 1383354)

Src/Compilers/VisualBasic/Portable/BasicCodeAnalysis.vbproj

@@ -689,6 +689,7 @@
     <Compile Include="Symbols\OverriddenMembersResult.vb" />
     <Compile Include="Symbols\ParameterSymbol.vb" />
     <Compile Include="Symbols\PEOrSourceOrMergedNamespaceSymbol.vb" />
+    <Compile Include="Symbols\PointerTypeSymbol.vb" />
     <Compile Include="Symbols\PreprocessingSymbol.vb" />
     <Compile Include="Symbols\PropertySignatureComparer.vb" />
     <Compile Include="Symbols\PropertySymbol.vb" />

Src/Compilers/VisualBasic/Portable/Symbols/ArrayTypeSymbol.vb

@@ -329,7 +329,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols
             ' And then hash that with the "T" type.
 
             Dim hashCode = 0
-            Dim current As ITypeSymbol = Me
+            Dim current As TypeSymbol = Me
             While (current.TypeKind = TypeKind.Array)
                 Dim cur = DirectCast(current, ArrayTypeSymbol)
                 hashCode = Hash.Combine(cur.Rank, hashCode)

Src/Compilers/VisualBasic/Portable/Symbols/Metadata/PE/MetadataDecoder.vb

@@ -230,7 +230,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols.Metadata.PE
         End Function
 
         Protected Overrides Function MakePointerTypeSymbol(type As TypeSymbol, customModifiers As ImmutableArray(Of ModifierInfo)) As TypeSymbol
-            Return GetUnsupportedMetadataTypeSymbol()
+            Return New PointerTypeSymbol(type, VisualBasicCustomModifier.Convert(customModifiers))
         End Function
 
         Protected Overrides Function SubstituteWithUnboundIfGeneric(type As TypeSymbol) As TypeSymbol

Src/Compilers/VisualBasic/Portable/Symbols/PointerTypeSymbol.vb

+Imports System.Collections.Immutable
+' Copyright (c) Microsoft Open Technologies, Inc.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols
+
+    ''' <summary>
+    ''' An error type symbol to represent a pointer type.
+    ''' Pointer types are not supported by VB language, but internally
+    ''' we need to be able to match them in signatures of methods 
+    ''' imported from metadata.
+    ''' </summary>
+    Friend NotInheritable Class PointerTypeSymbol
+        Inherits ErrorTypeSymbol
+
+        Private ReadOnly m_PointedAtType As TypeSymbol
+        Private ReadOnly m_CustomModifiers As ImmutableArray(Of CustomModifier)
+
+        Public Sub New(pointedAtType As TypeSymbol, customModifiers As ImmutableArray(Of CustomModifier))
+            Debug.Assert(pointedAtType IsNot Nothing)
+
+            m_PointedAtType = pointedAtType
+            m_CustomModifiers = customModifiers.NullToEmpty()
+        End Sub
+
+        Friend Overrides ReadOnly Property MangleName As Boolean
+            Get
+                Return False
+            End Get
+        End Property
+
+        Friend Overrides ReadOnly Property ErrorInfo As DiagnosticInfo
+            Get
+                Return ErrorFactory.ErrorInfo(ERRID.ERR_UnsupportedType1, String.Empty)
+            End Get
+        End Property
+
+        Public Overrides Function GetHashCode() As Integer
+            ' We don't want to blow the stack if we have a type like T***************...***,
+            ' so we do not recurse until we have a non-pointer. 
+
+            Dim indirections As Integer = 0
+            Dim current As PointerTypeSymbol = Me
+            Dim last As TypeSymbol
+
+            Do
+                indirections += 1
+                last = current.m_PointedAtType
+                current = TryCast(last, PointerTypeSymbol)
+            Loop While current IsNot Nothing
+
+            Return Hash.Combine(last, indirections)
+        End Function
+
+        Public Overrides Function Equals(obj As Object) As Boolean
+            If Me Is obj Then
+                Return True
+            End If
+
+            Dim other = TryCast(obj, PointerTypeSymbol)
+            Return other IsNot Nothing AndAlso other.m_PointedAtType.Equals(m_PointedAtType) AndAlso other.m_CustomModifiers.SequenceEqual(m_CustomModifiers)
+        End Function
+
+    End Class
+
+End Namespace

Src/Compilers/VisualBasic/Portable/Symbols/TypeSymbolExtensions.vb

@@ -207,7 +207,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols
 
                 If Not t1IsDefinition Then ' This is a generic instantiation
 
-                    If t1.OriginalDefinition IsNot t2.OriginalDefinition Then
+                    If t1.OriginalDefinition <> t2.OriginalDefinition Then
                         Return False ' different definition
                     End If
 

Src/Compilers/VisualBasic/Test/Symbol/SymbolsTests/Metadata/PE/LoadCustomModifiers.vb

@@ -93,7 +93,8 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.UnitTests.Symbols.Metadata.PE
 
             Dim p6Type As TypeSymbol = p6.Type
 
-            Assert.IsType(Of UnsupportedMetadataTypeSymbol)(p6Type)
+            Assert.IsType(Of PointerTypeSymbol)(p6Type)
+            Assert.Equal(ERRID.ERR_UnsupportedType1, p6Type.GetUseSiteErrorInfo().Code)
 
             Assert.False(m7.IsSub)
             Assert.Equal(1, m7.ReturnTypeCustomModifiers.Length)

Src/Compilers/VisualBasic/Test/Symbol/SymbolsTests/Source/OverridesTests.vb

@@ -6824,6 +6824,85 @@ BC31417: 'Friend Overrides Property Set r(Value As Object)' cannot override 'Fri
 
         End Sub
 
-    End Class
+        <WorkItem(1067044, "DevDiv")>
+        <Fact>
+        Sub Bug1067044()
+            Dim il = <![CDATA[
+.class public abstract auto ansi beforefieldinit C1
+       extends [mscorlib]System.Object
+{
+  .method public hidebysig newslot abstract virtual 
+          instance int32*  M1() cil managed
+  {
+  } // end of method C1::M1
+
+  .method family hidebysig specialname rtspecialname 
+          instance void  .ctor() cil managed
+  {
+    // Code size       8 (0x8)
+    .maxstack  8
+    IL_0000:  ldarg.0
+    IL_0001:  call       instance void [mscorlib]System.Object::.ctor()
+    IL_0006:  nop
+    IL_0007:  ret
+  } // end of method C1::.ctor
+
+} // end of class C1
 
+.class public abstract auto ansi beforefieldinit C2
+       extends C1
+{
+  .method public hidebysig virtual instance int32* 
+          M1() cil managed
+  {
+    // Code size       8 (0x8)
+    .maxstack  1
+    .locals init (int32* V_0)
+    IL_0000:  nop
+    IL_0001:  ldc.i4.0
+    IL_0002:  conv.u
+    IL_0003:  stloc.0
+    IL_0004:  br.s       IL_0006
+
+    IL_0006:  ldloc.0
+    IL_0007:  ret
+  } // end of method C2::M1
+
+  .method public hidebysig newslot abstract virtual 
+          instance void  M2() cil managed
+  {
+  } // end of method C2::M2
+
+  .method family hidebysig specialname rtspecialname 
+          instance void  .ctor() cil managed
+  {
+    // Code size       8 (0x8)
+    .maxstack  8
+    IL_0000:  ldarg.0
+    IL_0001:  call       instance void C1::.ctor()
+    IL_0006:  nop
+    IL_0007:  ret
+  } // end of method C2::.ctor
+
+} // end of class C2
+]]>
+
+            Dim source =
+               <compilation>
+                   <file name="a.vb">
+Public Class C3
+    Inherits C2
+
+    Public Overrides Sub M2()
+    End Sub
+End Class
+                    </file>
+               </compilation>
+
+            Dim compilation = CreateCompilationWithCustomILSource(source, il.Value, options:=TestOptions.DebugDll)
+
+            CompileAndVerify(compilation)
+        End Sub
+
+    End Class
 End Namespace