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fix: Add unit tests and improve analyzers for handling generated code and diagnostics #399

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BenjaminMichaelis merged 4 commits into from
Mar 9, 2026
Merged

fix: Add unit tests and improve analyzers for handling generated code and diagnostics #399

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1a54f21
fix: Add unit tests and improve analyzers for handling generated code…
BenjaminMichaelis Feb 24, 2026
ddb1145
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BenjaminMichaelis Feb 24, 2026
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BenjaminMichaelis Feb 24, 2026
4af7808
refactor: Extract HasGeneratedCodeAttribute extension method; use raw…
BenjaminMichaelis Mar 9, 2026
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25 changes: 25 additions & 0 deletions IntelliTect.Analyzer/IntelliTect.Analyzer.Test/AttributesOnSeparateLinesTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -390,6 +390,31 @@ static void Main()
await VerifyCSharpFix(test, fixTest);
}

[TestMethod]
[Description("Analyzer should not report on generated code")]
public void AttributesOnSameLine_InGeneratedCode_NoDiagnostic()
{
string test = @"using System;
using System.CodeDom.Compiler;

namespace ConsoleApp
{
class AAttribute : Attribute { }
class BAttribute : Attribute { }

[GeneratedCode(""tool"", ""1.0"")]
class Program
{
[A][B]
static void Main()
{
}
}
}";
// Should NOT produce a diagnostic for attributes on same line inside generated code
VerifyCSharpDiagnostic(test);
}

private static DiagnosticResult GetExpectedDiagnosticResult(int line, int col)
{
return new DiagnosticResult
Expand Down
289 changes: 208 additions & 81 deletions IntelliTect.Analyzer/IntelliTect.Analyzer.Test/FavorEnumeratorDirectoryCallsTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -11,25 +11,27 @@ public class FavorEnumeratorDirectoryCallsTests : CodeFixVerifier
[TestMethod]
public void UsageOfDirectoryGetFiles_ProducesInfoMessage()
{
string source = @"using System;
using System.Diagnostics;
using System.IO;
string source = """
using System;
using System.Diagnostics;
using System.IO;

namespace ConsoleApp5
{
class Program
{
static void Main(string[] args)
{
string[] files = Directory.GetFiles(AppDomain.CurrentDomain.BaseDirectory);
namespace ConsoleApp5
{
class Program
{
static void Main(string[] args)
{
string[] files = Directory.GetFiles(AppDomain.CurrentDomain.BaseDirectory);

foreach (string file in files)
{
Console.WriteLine($""File found: ${file}"");
}
}
}
}";
foreach (string file in files)
{
Console.WriteLine($"File found: ${file}");
}
}
}
}
""";
VerifyCSharpDiagnostic(source,
new DiagnosticResult
{
Expand All @@ -46,26 +48,28 @@ static void Main(string[] args)
[TestMethod]
public void DeclarationOfOtherDirectoryGetFiles_ProducesNothing()
{
string source = @"using System;
using System.Diagnostics;
using System.IO;
string source = """
using System;
using System.Diagnostics;
using System.IO;

namespace ConsoleApp5
{
public static class Directory {
public static string[] GetFiles(string path) => Array.Empty<string>();
}
namespace ConsoleApp5
{
public static class Directory {
public static string[] GetFiles(string path) => Array.Empty<string>();
}


class Program
{
static void Main(string[] args)
{
string[] files = Directory.GetFiles(AppDomain.CurrentDomain.BaseDirectory);
class Program
{
static void Main(string[] args)
{
string[] files = Directory.GetFiles(AppDomain.CurrentDomain.BaseDirectory);

}
}
}";
}
}
}
""";
VerifyCSharpDiagnostic(source);
}

Expand All @@ -79,25 +83,27 @@ protected override DiagnosticAnalyzer GetCSharpDiagnosticAnalyzer()
[TestMethod]
public void UsageOfDirectoryGetDirectories_ProducesInfoMessage()
{
string source = @"using System;
using System.Diagnostics;
using System.IO;
string source = """
using System;
using System.Diagnostics;
using System.IO;

namespace ConsoleApp5
{
class Program
{
static void Main(string[] args)
{
string[] files = Directory.GetDirectories(AppDomain.CurrentDomain.BaseDirectory);
namespace ConsoleApp5
{
class Program
{
static void Main(string[] args)
{
string[] files = Directory.GetDirectories(AppDomain.CurrentDomain.BaseDirectory);

foreach (string file in files)
{
Console.WriteLine($""File found: ${file}"");
}
}
}
}";
foreach (string file in files)
{
Console.WriteLine($"File found: ${file}");
}
}
}
}
""";
VerifyCSharpDiagnostic(source,
new DiagnosticResult
{
Expand All @@ -114,52 +120,173 @@ static void Main(string[] args)
[TestMethod]
public void DeclarationOfOtherDirectoryGetDirectories_ProducesNothing()
{
string source = @"using System;
using System.Diagnostics;
using System.IO;
string source = """
using System;
using System.Diagnostics;
using System.IO;

namespace ConsoleApp5
{
public static class Directory {
public static string[] GetDirectories(string path) => Array.Empty<string>();
}
namespace ConsoleApp5
{
public static class Directory {
public static string[] GetDirectories(string path) => Array.Empty<string>();
}


class Program
{
static void Main(string[] args)
{
string[] files = Directory.GetDirectories(AppDomain.CurrentDomain.BaseDirectory);
class Program
{
static void Main(string[] args)
{
string[] files = Directory.GetDirectories(AppDomain.CurrentDomain.BaseDirectory);

}
}
}";
}
}
}
""";
VerifyCSharpDiagnostic(source);
}

[TestMethod]
[Description("Issue 53")]
public void Diagnostic_HandlesMemberAccess()
{
string source = @"
using System;
string source = """

namespace Namespace
{
class Program
{
static void Main(string[] args)
using System;

namespace Namespace
{
class Program
{
static void Main(string[] args)
{
int selection;
if (!int.TryParse(Console.ReadLine(), out selection))
{
selection = 0;
}
}
}
}
""";
VerifyCSharpDiagnostic(source);
}

[TestMethod]
[Description("Cast<IdentifierNameSyntax>() throws InvalidCastException on generic method calls")]
public void GenericMethodCallOnDirectory_DoesNotThrow()
{
int selection;
if (!int.TryParse(Console.ReadLine(), out selection))
{
selection = 0;
}
// memberAccess.ChildNodes().Cast<IdentifierNameSyntax>() will throw
// if any child node is not IdentifierNameSyntax (e.g. GenericNameSyntax).
// This test uses a generic method call on a class named Directory.
string source = """

using System;
using System.Collections.Generic;

namespace ConsoleApp
{
public static class Directory
{
public static List<T> GetItems<T>() => new List<T>();
}

class Program
{
static void Main(string[] args)
{
var items = Directory.GetItems<string>();
}
}
}
""";
VerifyCSharpDiagnostic(source);
}
}
}
";

[TestMethod]
[Description("Analyzer should not report when symbol is unresolved (compile error)")]
public void UnresolvableDirectoryType_NoDiagnostic()
{
// When symbol.Symbol is null it means the code has a compile error,
// not that it's System.IO.Directory. Should not produce a false positive.
string source = """

namespace ConsoleApp
{
class Program
{
static void Main(string[] args)
{
var files = Directory.GetFiles(".");
}
}
}
""";
// No 'using System.IO' so Directory is unresolvable — should NOT produce diagnostic
VerifyCSharpDiagnostic(source);
}

[TestMethod]
[Description("Detect fully-qualified System.IO.Directory.GetFiles()")]
public void FullyQualifiedDirectoryGetFiles_ProducesInfoMessage()
{
string source = """

using System;

namespace ConsoleApp
{
class Program
{
static void Main(string[] args)
{
string[] files = System.IO.Directory.GetFiles(AppDomain.CurrentDomain.BaseDirectory);
}
}
}
""";
VerifyCSharpDiagnostic(source,
new DiagnosticResult
{
Id = "INTL0301",
Severity = DiagnosticSeverity.Info,
Message = "Favor using the method `EnumerateFiles` over the `GetFiles` method",
Locations =
[
new DiagnosticResultLocation("Test0.cs", 10, 30)
]
});
}

[TestMethod]
[Description("Detect fully-qualified System.IO.Directory.GetDirectories()")]
public void FullyQualifiedDirectoryGetDirectories_ProducesInfoMessage()
{
string source = """

using System;

namespace ConsoleApp
{
class Program
{
static void Main(string[] args)
{
string[] dirs = System.IO.Directory.GetDirectories(AppDomain.CurrentDomain.BaseDirectory);
}
}
}
""";
VerifyCSharpDiagnostic(source,
new DiagnosticResult
{
Id = "INTL0302",
Severity = DiagnosticSeverity.Info,
Message = "Favor using the method `EnumerateDirectories` over the `GetDirectories` method",
Locations =
[
new DiagnosticResultLocation("Test0.cs", 10, 29)
]
});
}
}
}
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