Skip to content

Add runtime NullReferenceException validation to foreach null iteration tests #80839

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
CyrusNajmabadi merged 3 commits into from
Oct 23, 2025
Merged

Add runtime NullReferenceException validation to foreach null iteration tests #80839

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
f41fcb4
Initial plan
Copilot Oct 21, 2025
06293f2
Update foreach null tests to validate runtime NullReferenceException
Copilot Oct 21, 2025
4dc5da8
Add VerifyDiagnostics() to CompileAndVerify calls
Copilot Oct 21, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
102 changes: 85 additions & 17 deletions src/Compilers/CSharp/Test/Semantic/Semantics/ForEachTests.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -92,14 +92,21 @@ class C
{
static void Main()
{
foreach (int x in default(int[]))
try
{
foreach (int x in default(int[]))
{
Copy link
Contributor

@AlekseyTs AlekseyTs Oct 22, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

{

I think it will be useful to observe that the loop didn't execute, consider printing something from the loop, or throw a different exception.

Copy link
Contributor

@AlekseyTs AlekseyTs Oct 23, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

@CyrusNajmabadi Did you see this comment?

Copy link
Member

@CyrusNajmabadi CyrusNajmabadi Oct 23, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

i did. I didn't think it was worthwhile enough, and didn't think the comment was blocking. So i went ahead with merging.

Copy link
Contributor

@AlekseyTs AlekseyTs Oct 23, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

i did. I didn't think it was worthwhile enough, and didn't think the comment was blocking. So i went ahead with merging.

Just making sure you saw it

}
}
catch (System.NullReferenceException)
{
System.Console.Write("NullReferenceException");
}
}
}
""";

CreateCompilation(source).VerifyEmitDiagnostics();
CompileAndVerify(source, expectedOutput: "NullReferenceException").VerifyDiagnostics();
}

[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/45616")]
Expand All @@ -110,14 +117,21 @@ class C
{
static void Main()
{
foreach (char c in default(string))
try
{
foreach (char c in default(string))
{
}
}
catch (System.NullReferenceException)
{
System.Console.Write("NullReferenceException");
}
}
}
""";

CreateCompilation(source).VerifyEmitDiagnostics();
CompileAndVerify(source, expectedOutput: "NullReferenceException").VerifyDiagnostics();
}

[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/45616")]
Expand All @@ -129,14 +143,21 @@ class C
{
static void Main()
{
foreach (var x in default(IEnumerable<int>))
try
{
foreach (var x in default(IEnumerable<int>))
{
}
}
catch (System.NullReferenceException)
{
System.Console.Write("NullReferenceException");
}
}
}
""";

CreateCompilation(source).VerifyEmitDiagnostics();
CompileAndVerify(source, expectedOutput: "NullReferenceException").VerifyDiagnostics();
}

[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/45616")]
Expand All @@ -148,14 +169,21 @@ class C
{
static void Main()
{
foreach (var x in (IEnumerable<int>)null)
try
{
foreach (var x in (IEnumerable<int>)null)
{
}
}
catch (System.NullReferenceException)
{
System.Console.Write("NullReferenceException");
}
}
}
""";

CreateCompilation(source).VerifyEmitDiagnostics();
CompileAndVerify(source, expectedOutput: "NullReferenceException").VerifyDiagnostics();
}

[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/45616")]
Expand All @@ -166,14 +194,21 @@ class C
{
static void Main()
{
foreach (int x in (int[])null)
try
{
foreach (int x in (int[])null)
{
}
}
catch (System.NullReferenceException)
{
System.Console.Write("NullReferenceException");
}
}
}
""";

CreateCompilation(source).VerifyEmitDiagnostics();
CompileAndVerify(source, expectedOutput: "NullReferenceException").VerifyDiagnostics();
}

[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/45616")]
Expand All @@ -184,14 +219,21 @@ class C
{
static void Main()
{
foreach (char c in (string)null)
try
{
foreach (char c in (string)null)
{
}
}
catch (System.NullReferenceException)
{
System.Console.Write("NullReferenceException");
}
}
}
""";

CreateCompilation(source).VerifyEmitDiagnostics();
CompileAndVerify(source, expectedOutput: "NullReferenceException").VerifyDiagnostics();
}

[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/45616")]
Expand Down Expand Up @@ -366,14 +408,21 @@ class C
{
static void Main()
{
foreach (var x in (dynamic)null)
try
{
foreach (var x in (dynamic)null)
{
}
}
catch (System.NullReferenceException)
{
System.Console.Write("NullReferenceException");
}
}
}
""";

CreateCompilation(source, targetFramework: TargetFramework.StandardAndCSharp).VerifyEmitDiagnostics();
CompileAndVerify(source, targetFramework: TargetFramework.StandardAndCSharp, expectedOutput: "NullReferenceException").VerifyDiagnostics();
}

[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/45616")]
Expand All @@ -384,14 +433,21 @@ class C
{
static void Main()
{
foreach (int x in (int[,])null)
try
{
foreach (int x in (int[,])null)
{
}
}
catch (System.NullReferenceException)
{
System.Console.Write("NullReferenceException");
}
}
}
""";

CreateCompilation(source).VerifyEmitDiagnostics();
CompileAndVerify(source, expectedOutput: "NullReferenceException").VerifyDiagnostics();
}

[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/45616")]
Expand Down Expand Up @@ -451,6 +507,18 @@ public void ForeachOnNullCastToConstrainedTypeParameter()
using System.Collections.Generic;
class C
{
static void Main()
{
try
{
M<List<int>>();
}
catch (System.NullReferenceException)
{
System.Console.Write("NullReferenceException");
}
}

static void M<T>() where T : class, IEnumerable<int>
{
foreach (var x in (T)null)
Expand All @@ -460,7 +528,7 @@ static void M<T>() where T : class, IEnumerable<int>
}
""";

CreateCompilation(source).VerifyEmitDiagnostics();
CompileAndVerify(source, expectedOutput: "NullReferenceException").VerifyDiagnostics();
}

[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/45616")]
Expand Down