Fix crash in...

Fix crash in VisualBasic.Binder.MemberLookup.AddLookupSymbolsInfoInTypeParameter when it is called with Cref TypeParameter. (#21586)

Fixes https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_workitems?id=410932.

The fix mimics the way C# compiler handles Cref TypeParameters in the similar API.

src/Compilers/CSharp/Test/Symbol/DocumentationComments/CrefTests.cs

@@ -6599,5 +6599,35 @@ private static Symbol[] GetCrefOriginalDefinitions(SemanticModel model, IEnumera
         {
             return crefs.Select(syntax => model.GetSymbolInfo(syntax).Symbol).Select(symbol => (object)symbol == null ? null : (Symbol)symbol.OriginalDefinition).ToArray();
         }
+
+        [Fact]
+        [WorkItem(410932, "https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_workitems?id=410932")]
+        public void LookupOnCrefTypeParameter()
+        {
+            var source = @"
+class Test
+{
+    T F<T>()
+    {
+    }
+
+    /// <summary>
+    /// <see cref=""F{U}()""/>
+    /// </summary>
+    void S()
+    { }
+}
+";
+
+            var compilation = CreateCompilationWithMscorlibAndDocumentationComments(source);
+            var tree = compilation.SyntaxTrees[0];
+            var model = compilation.GetSemanticModel(tree);
+            var crefSyntax = (NameMemberCrefSyntax)GetCrefSyntaxes(compilation).Single();
+
+            var name = ((GenericNameSyntax)crefSyntax.Name).TypeArgumentList.Arguments.Single();
+            Assert.Equal("U", name.ToString());
+            var typeParameter = (TypeParameterSymbol)model.GetSymbolInfo(name).Symbol;
+            Assert.Empty(model.LookupSymbols(name.SpanStart, typeParameter, "GetAwaiter"));
+        }
     }
 }

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

@@ -1995,6 +1995,10 @@ ExitForFor:
                                                                     typeParameter As TypeParameterSymbol,
                                                                     options As LookupOptions,
                                                                     binder As Binder)
+                If typeParameter.TypeParameterKind = TypeParameterKind.Cref Then
+                    Return
+                End If
+
                 AddLookupSymbolsInfoInTypeParameterNoExtensionMethods(nameSet, typeParameter, options, binder)
 
                 ' Search for extension methods.

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

@@ -12410,5 +12410,40 @@ DashDash
                 stringMapper:=Function(o) StringReplace(o, System.IO.Path.Combine(TestHelpers.AsXmlCommentText(path), "- - -.xml"), "**FILE**"), ensureEnglishUICulture:=True)
         End Sub
 
+        <Fact>
+        <WorkItem(410932, "https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_workitems?id=410932")>
+        Public Sub LookupOnCrefTypeParameter()
+
+            Dim sources =
+<compilation>
+    <file name="a.vb">
+        <![CDATA[
+Public Class Test
+    Function F(Of T)() As T
+    End Function
+
+    ''' <summary>
+    ''' <see cref="F(Of U)()"/>
+    ''' </summary>
+    Public Sub S()
+    End Sub
+End Class
+]]>
+    </file>
+</compilation>
+
+            Dim compilation = CreateCompilationWithMscorlibAndVBRuntime(
+                sources,
+                options:=TestOptions.ReleaseDll)
+
+
+            Dim tree = compilation.SyntaxTrees(0)
+            Dim model = compilation.GetSemanticModel(tree)
+
+            Dim name = FindNodesOfTypeFromText(Of NameSyntax)(tree, "U").Single()
+            Dim typeParameter = DirectCast(model.GetSymbolInfo(name).Symbol, TypeParameterSymbol)
+            Assert.Empty(model.LookupSymbols(name.SpanStart, typeParameter, "GetAwaiter"))
+        End Sub
+
     End Class
 End Namespace

src/EditorFeatures/CSharpTest/QuickInfo/SemanticQuickInfoSourceTests.cs

@@ -4992,5 +4992,28 @@ static void Main(string[] args)
 }",
                 MainDescription($"({FeaturesResources.local_variable}) ref int i"));
         }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.QuickInfo)]
+        [WorkItem(410932, "https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_workitems?id=410932")]
+        public async Task TestGenericMethodInDocComment()
+        {
+            await TestAsync(
+@"
+class Test
+{
+    T F<T>()
+    {
+        F<T>();
+    }
+
+    /// <summary>
+    /// <see cref=""F$${T}()""/>
+    /// </summary>
+    void S()
+    { }
+}
+",
+            MainDescription("T Test.F<T>()"));
+        }
     }
 }

src/EditorFeatures/VisualBasicTest/QuickInfo/SemanticQuickInfoSourceTests.vb

@@ -2089,5 +2089,25 @@ End Class
 ",
                  Documentation("String http://microsoft.com Nothing cat"))
         End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.QuickInfo)>
+        <WorkItem(410932, "https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_workitems?id=410932")>
+        Public Async Function TestGenericMethodInDocComment() As Task
+            Await TestWithImportsAsync(<Text><![CDATA[
+Public Class Test
+    Function F(Of T)() As T
+        F(Of T)()
+    End Function
+
+    ''' <summary>
+    ''' <see cref="F$$(Of T)()"/>
+    ''' </summary>
+    Public Sub S()
+    End Sub
+End Class
+                ]]></Text>.NormalizedValue,
+             MainDescription("Function Test.F(Of T)() As T"))
+        End Function
+
     End Class
 End Namespace