VB: Prevent SemanticModel from crashing on an invalid syntax used as a type parameter. Fixes #436.

***NO_CI***
 (changeset 1386442)

Src/Compilers/VisualBasic/Portable/Binding/DocumentationCommentCrefBinder.vb

@@ -293,7 +293,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
                                 End If
 
                             Case Else
-                                Throw ExceptionUtilities.UnexpectedValue(typeSyntax.Kind)
+                                ' An error case
                         End Select
                     Next
                 End If
@@ -309,11 +309,16 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             Dim parent As VisualBasicSyntaxNode = name.Parent
 
             ' Type parameter
-            If name.Kind = SyntaxKind.IdentifierName AndAlso parent IsNot Nothing AndAlso parent.Kind = SyntaxKind.TypeArgumentList Then
-                Dim identifier = DirectCast(name, IdentifierNameSyntax)
+            If parent IsNot Nothing AndAlso parent.Kind = SyntaxKind.TypeArgumentList Then
                 Dim ordinal As Integer = DirectCast(parent, TypeArgumentListSyntax).Arguments.IndexOf(name)
-                Return ImmutableArray.Create(Of Symbol)(
-                    New CrefTypeParameterSymbol(ordinal, identifier.Identifier.ValueText, identifier))
+
+                If name.Kind = SyntaxKind.IdentifierName Then
+                    Dim identifier = DirectCast(name, IdentifierNameSyntax)
+                    Return ImmutableArray.Create(Of Symbol)(New CrefTypeParameterSymbol(ordinal, identifier.Identifier.ValueText, identifier))
+                End If
+
+                ' An error case
+                Return ImmutableArray.Create(Of Symbol)(New CrefTypeParameterSymbol(ordinal, StringConstants.NamedSymbolErrorName, name))
             End If
 
             ' Names considered to be checked for color-color case are Identifier or Generic names which 
@@ -835,7 +840,9 @@ lAgain:
                         typeParameterSymbols(i) = created
 
                     Case Else
-                        Throw ExceptionUtilities.UnexpectedValue(typeSyntax.Kind)
+                        ' An error case
+                        created = New CrefTypeParameterSymbol(i, StringConstants.NamedSymbolErrorName, typeSyntax)
+                        typeParameterSymbols(i) = created
                 End Select
 
                 typeParameters(created.Name) = created

Src/Compilers/VisualBasic/Portable/Symbols/Source/CrefTypeParameterSymbol.vb

@@ -25,7 +25,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Symbols
         Private ReadOnly _name As String
         Private ReadOnly _syntaxReference As SyntaxReference
 
-        Public Sub New(ordinal As Integer, name As String, syntax As IdentifierNameSyntax)
+        Public Sub New(ordinal As Integer, name As String, syntax As TypeSyntax)
             Me._ordinal = ordinal
             Me._name = name
             Me._syntaxReference = syntax.GetReference()

Src/Compilers/VisualBasic/Test/Symbol/DocumentationComments/DocCommentTests.vb

@@ -12090,5 +12090,125 @@ xmlDoc)
         End Sub
 
 #End Region
+
+        <WorkItem(1087447, "DevDiv"), WorkItem(436, "CodePlex")>
+        <Fact>
+        Public Sub Bug1087447_01()
+            Dim compilation = CompileCheckDiagnosticsAndXmlDocument(
+<compilation name="EmptyCref">
+    <file name="a.vb">
+        <![CDATA[
+''' <summary>
+''' <see cref="C(Of Integer).f()"/>
+''' </summary>
+Class C(Of T)
+    Sub f()
+    End Sub
+End Class
+
+]]>
+    </file>
+</compilation>,
+<error><![CDATA[
+BC42309: XML comment has a tag with a 'cref' attribute 'C(Of Integer).f()' that could not be resolved.
+''' <see cref="C(Of Integer).f()"/>
+         ~~~~~~~~~~~~~~~~~~~~~~~~
+]]></error>,
+<xml>
+    <![CDATA[
+<?xml version="1.0"?>
+<doc>
+<assembly>
+<name>
+EmptyCref
+</name>
+</assembly>
+<members>
+<member name="T:C`1">
+ <summary>
+ <see cref="!:C(Of Integer).f()"/>
+ </summary>
+</member>
+</members>
+</doc>
+]]>
+</xml>)
+
+            Dim tree = compilation.SyntaxTrees(0)
+            Dim model = compilation.GetSemanticModel(tree)
+
+            Dim node1 = tree.GetRoot().DescendantNodes(descendIntoTrivia:=True).OfType(Of IdentifierNameSyntax)().Where(Function(n) n.Identifier.ValueText = "f").Single()
+
+            Dim symbolInfo1 = model.GetSymbolInfo(node1.Parent)
+
+            Assert.Equal("Sub C(Of ?).f()", symbolInfo1.Symbol.ToTestDisplayString())
+
+            Dim node = tree.GetRoot().DescendantNodes(descendIntoTrivia:=True).OfType(Of TypeSyntax)().Where(Function(n) n.ToString() = "Integer").Single()
+
+            Dim symbolInfo = model.GetSymbolInfo(node)
+
+            Assert.Equal("?", symbolInfo.Symbol.ToTestDisplayString())
+
+        End Sub
+
+        <WorkItem(1087447, "DevDiv"), WorkItem(436, "CodePlex")>
+        <Fact>
+        Public Sub Bug1087447_02()
+            Dim compilation = CompileCheckDiagnosticsAndXmlDocument(
+<compilation name="EmptyCref">
+    <file name="a.vb">
+        <![CDATA[
+''' <summary>
+''' <see cref="C(Of System.Int32).f()"/>
+''' </summary>
+Class C(Of T)
+    Sub f()
+    End Sub
+End Class
+
+]]>
+    </file>
+</compilation>,
+<error><![CDATA[
+BC42309: XML comment has a tag with a 'cref' attribute 'C(Of System.Int32).f()' that could not be resolved.
+''' <see cref="C(Of System.Int32).f()"/>
+         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+]]></error>,
+<xml>
+    <![CDATA[
+<?xml version="1.0"?>
+<doc>
+<assembly>
+<name>
+EmptyCref
+</name>
+</assembly>
+<members>
+<member name="T:C`1">
+ <summary>
+ <see cref="!:C(Of System.Int32).f()"/>
+ </summary>
+</member>
+</members>
+</doc>
+]]>
+</xml>)
+
+            Dim tree = compilation.SyntaxTrees(0)
+            Dim model = compilation.GetSemanticModel(tree)
+
+            Dim node1 = tree.GetRoot().DescendantNodes(descendIntoTrivia:=True).OfType(Of IdentifierNameSyntax)().Where(Function(n) n.Identifier.ValueText = "f").Single()
+
+            Dim symbolInfo1 = model.GetSymbolInfo(node1.Parent)
+
+            Assert.Equal("Sub C(Of ?).f()", symbolInfo1.Symbol.ToTestDisplayString())
+
+            Dim node = tree.GetRoot().DescendantNodes(descendIntoTrivia:=True).OfType(Of TypeSyntax)().Where(Function(n) n.ToString() = "System.Int32").Single()
+
+            Dim symbolInfo = model.GetSymbolInfo(node)
+
+            Assert.Equal("?", symbolInfo.Symbol.ToTestDisplayString())
+        End Sub
+
     End Class
 End Namespace