Tests to showcase problem with semantic model

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

@@ -1297,6 +1297,28 @@ x = x               'BIND1:"x"
             Assert.Equal("System.Object", typeInfo.Type.ToTestDisplayString)
         End Sub
 
+        <Fact()>
+        Public Sub CompilerTest21662()
+            Dim compilation = CompilationUtils.CreateCompilation(
+    <compilation name="CompilerTest21662">
+        <file name="a.vb">
+Imports System
+Module Module1
+    Sub Main()
+        Dim product = (id:=1, [DateTime]:=DateTime.Now.ToString())
+    End Sub
+End Module
+        </file>
+    </compilation>, parseOptions:=TestOptions.Script)
+
+            Dim model = GetSemanticModel(compilation, "a.vb")
+            Dim tree = compilation.SyntaxTrees(0)
+
+            Dim node = FindNodeFromText(tree, "[DateTime]")
+            Dim dateTimeNameInfo = model.GetSymbolInfo(node)
+            Assert.Null(dateTimeNameInfo.Symbol)
+        End Sub
+
         <Fact()>
         Public Sub BindingModuleMemberInQualifiedExpressionWithGlobal()
             Dim compilation = CompilationUtils.CreateCompilationWithMscorlib40(

src/EditorFeatures/VisualBasicTest/SimplifyTypeNames/SimplifyTypeNamesTests.vb

@@ -2561,5 +2561,23 @@ Module Module1
 End Module",
                 options:=PreferIntrinsicTypeInMemberAccess())
         End Function
+
+        <WorkItem(15996, "https://github.com/dotnet/roslyn/issues/15996")>
+        <Fact(), Trait(Traits.Feature, Traits.Features.CodeActionsSimplifyTypeNames)>
+        Public Async Function TestMemberOfBuiltInType32() As Task
+            Await TestInRegularAndScriptAsync(
+"Imports System
+Module Module1
+    Sub Main()
+        Dim product = (id:=1, [[|DateTime|]]:=DateTime.Now.ToString())
+    End Sub
+End Module",
+"Imports System
+Module Module1
+    Sub Main()
+        Dim product = (id:=1, [DateTime]:=DateTime.Now.ToString())
+    End Sub
+End Module")
+        End Function
     End Class
 End Namespace