dotnet#1638: use SpecialType for checking parameter type string

thanks @mavasani for the hint.

src/Microsoft.CodeQuality.Analyzers/Core/ApiDesignGuidelines/StringBuilderAppendShouldNotTakeSubstring.cs

@@ -89,7 +89,7 @@ private void Action(OperationAnalysisContext context)
                     && invokedMethod.Name == nameof(StringBuilder.Append))
                 {
                     var parameters = invokedMethod.Parameters;
-                    if (parameters.Length == 1 && parameters[0].Type.Name == nameof(String))
+                    if (parameters.Length == 1 && parameters[0].Type.SpecialType == SpecialType.System_String)
                     {
                         IArgumentOperation argument = invocation.Arguments.FirstOrDefault();
                         if (argument.Value is IInvocationOperation invocationExpression

src/Microsoft.CodeQuality.Analyzers/UnitTests/ApiDesignGuidelines/StringBuilderAppendShouldNotTakeSubstringTests.Fixer.cs

@@ -1,16 +1,12 @@
 using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.CodeFixes;
 using Microsoft.CodeAnalysis.Diagnostics;
 using Test.Utilities;
 using Xunit;
 
 namespace Microsoft.CodeQuality.Analyzers.ApiDesignGuidelines.UnitTests
 {
-    public class StringBuilderAppendShouldNotTakeSubstringFixerTests : CodeFixTestBase
+    public class StringBuilderAppendShouldNotTakeSubstringFixerTestsCsharp : CodeFixTestBase
     {
         protected override DiagnosticAnalyzer GetCSharpDiagnosticAnalyzer()
         {
@@ -24,12 +20,12 @@ protected override DiagnosticAnalyzer GetBasicDiagnosticAnalyzer()
 
         protected override CodeFixProvider GetCSharpCodeFixProvider()
         {
-            return new StringBuilderAppendShouldNotTakeSubstringFixer();
+            return new StringBuilderAppendShouldNotTakeSubstringCsharpFixer();
         }
 
         protected override CodeFixProvider GetBasicCodeFixProvider()
         {
-            return new StringBuilderAppendShouldNotTakeSubstringFixer();
+            throw new NotSupportedException();
         }
 
         [Fact]
@@ -62,34 +58,6 @@ public string Append(string text)
             VerifyCSharpFix(Code, FixedCode);
         }
 
-        [Fact]
-        public void FixesExample1FromTicketBasic()
-        {
-            const string Code = @"
-Imports System.Text
-
-Public Class C
-    Public Function Append(ByVal text As String) As String
-        Dim sb = New StringBuilder()
-        sb.Append(text.Substring(0, 6))
-        Return sb.ToString()
-    End Function
-End Class
-";
-            const string FixedCode = @"
-Imports System.Text
-
-Public Class C
-    Public Function Append(ByVal text As String) As String
-        Dim sb = New StringBuilder()
-        sb.Append(text, 0, 6)
-        Return sb.ToString()
-    End Function
-End Class
-";
-            VerifyBasicFix(Code, FixedCode);
-        }
-
         [Fact]
         public void FixesExample2FromTicket()
         {
@@ -120,34 +88,6 @@ public string Append(string text)
             VerifyCSharpFix(Code, FixedCode);
         }
 
-        [Fact]
-        public void FixesExample2FromTicketBasic()
-        {
-            const string Code = @"
-Imports System.Text
-
-Public Class C
-    Public Function Append(ByVal text As String) As String
-        Dim sb = New StringBuilder()
-        sb.Append(text.Substring(2))
-        Return sb.ToString()
-    End Function
-End Class
-";
-            const string FixedCode = @"
-Imports System.Text
-
-Public Class C
-    Public Function Append(ByVal text As String) As String
-        Dim sb = New StringBuilder()
-        sb.Append(text, 2, text.Length - 2)
-        Return sb.ToString()
-    End Function
-End Class
-";
-            VerifyBasicFix(Code, FixedCode);
-        }
-
         [Fact(Skip = "not working yet")]
         public void FixesAllExamplesFromTicket()
         {
@@ -180,6 +120,85 @@ public string Append(string text)
 }";
             VerifyCSharpFixAll(Code, FixedCode);
         }
+    }
+
+    public class StringBuilderAppendShouldNotTakeSubstringFixerTestsBasic : CodeFixTestBase
+    {
+        protected override DiagnosticAnalyzer GetCSharpDiagnosticAnalyzer()
+        {
+            return new StringBuilderAppendShouldNotTakeSubstring();
+        }
+
+        protected override DiagnosticAnalyzer GetBasicDiagnosticAnalyzer()
+        {
+            return new StringBuilderAppendShouldNotTakeSubstring();
+        }
+
+        protected override CodeFixProvider GetCSharpCodeFixProvider()
+        {
+            throw new NotSupportedException();
+        }
+
+        protected override CodeFixProvider GetBasicCodeFixProvider()
+        {
+            return new StringBuilderAppendShouldNotTakeSubstringBasicFixer();
+        }
+
+        [Fact]
+        public void FixesExample1FromTicket()
+        {
+            const string Code = @"
+Imports System.Text
+
+Public Class C
+    Public Function Append(ByVal text As String) As String
+        Dim sb = New StringBuilder()
+        sb.Append(text.Substring(0, 6))
+        Return sb.ToString()
+    End Function
+End Class
+";
+            const string FixedCode = @"
+Imports System.Text
+
+Public Class C
+    Public Function Append(ByVal text As String) As String
+        Dim sb = New StringBuilder()
+        sb.Append(text, 0, 6)
+        Return sb.ToString()
+    End Function
+End Class
+";
+            VerifyBasicFix(Code, FixedCode);
+        }
+
+        [Fact]
+        public void FixesExample2FromTicketBasic()
+        {
+            const string Code = @"
+Imports System.Text
+
+Public Class C
+    Public Function Append(ByVal text As String) As String
+        Dim sb = New StringBuilder()
+        sb.Append(text.Substring(2))
+        Return sb.ToString()
+    End Function
+End Class
+";
+            const string FixedCode = @"
+Imports System.Text
+
+Public Class C
+    Public Function Append(ByVal text As String) As String
+        Dim sb = New StringBuilder()
+        sb.Append(text, 2, text.Length - 2)
+        Return sb.ToString()
+    End Function
+End Class
+";
+            VerifyBasicFix(Code, FixedCode);
+        }
 
         [Fact(Skip = "not working yet")]
         public void FixesAllExamplesFromTicketBasic()
@@ -212,4 +231,5 @@ End Class
             VerifyBasicFixAll(Code, FixedCode);
         }
     }
+
 }