NRE at Microsoft.CodeAnalysis.SymbolKey.NonDeclarationSymbolKey`1.<EnumerateSymbols>

[mavasani]

I do not have a repro, but am hitting this NRE very often while typing. It seems to be from RenameTrackingTaggerProvider.

I have InstallDogfood bits from master which are a day old (1.03.0.60503)

Dump saved at: \\<%Internal_Share%>\public\dumps\11092\devenv.dmp

Message: Object reference not set to an instance of an object.

Call stack:

at Microsoft.CodeAnalysis.SymbolKey.NonDeclarationSymbolKey1.<EnumerateSymbols>d__5.MoveNext() at Microsoft.CodeAnalysis.SymbolKey.NonDeclarationSymbolKey1..ctor(TSymbol symbol, Visitor visitor)
at Microsoft.CodeAnalysis.SymbolKey.Visitor.VisitLocal(ILocalSymbol localSymbol)
at Microsoft.CodeAnalysis.CSharp.Symbols.LocalSymbol.Accept[TResult](SymbolVisitor`1 visitor)
at Microsoft.CodeAnalysis.SymbolKey.GetOrCreate(ISymbol symbol, Visitor visitor)
at Microsoft.CodeAnalysis.FindSymbols.SymbolFinder.d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.CodeAnalysis.Editor.Implementation.RenameTracking.RenameTrackingTaggerProvider.TrackingSession.d__22.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
at Microsoft.CodeAnalysis.Editor.Implementation.RenameTracking.RenameTrackingTaggerProvider.TrackingSession.d__20.MoveNext()

[mavasani]

I am hitting this frequently even with the latest InstallDogfood bits from master - I am marking this as urgency soon and rolling back to older Roslyn bits :-(

[mavasani]

FYI @dpoeschl

[mavasani]

Note that all the crashes seem to occur when there are errors in code being edited. I rolled back to Roslyn bits from 27th April and still hitting this crash. Rename tracking diagnostic is marked as NotConfigurable, so I guess it cannot be suppressed either.

[mavasani]

I rolled back to bits from the 26th April and haven't seen any more crashes. Probably something checked in during these 2 days that regressed this?

[mavasani]

Commented too soon - got the same exception on bits from 26th as well :-(

[jmarolf]

@mavasani ran into this just now.

   at Microsoft.CodeAnalysis.SymbolKey.NonDeclarationSymbolKey`1.<EnumerateSymbols>d__5.MoveNext()
   at Microsoft.CodeAnalysis.SymbolKey.NonDeclarationSymbolKey`1..ctor(TSymbol symbol, Visitor visitor)
   at Microsoft.CodeAnalysis.SymbolKey.Visitor.VisitLocal(ILocalSymbol localSymbol)
   at Microsoft.CodeAnalysis.CSharp.Symbols.LocalSymbol.Accept[TResult](SymbolVisitor`1 visitor)
   at Microsoft.CodeAnalysis.SymbolKey.GetOrCreate(ISymbol symbol, Visitor visitor)
   at Microsoft.CodeAnalysis.FindSymbols.SymbolFinder.<FindSourceDefinitionWorkerAsync>d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.CodeAnalysis.Editor.Implementation.RenameTracking.RenameTrackingTaggerProvider.TrackingSession.<DetermineIfRenamableSymbolAsync>d__22.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
   at Microsoft.CodeAnalysis.Editor.Implementation.RenameTracking.RenameTrackingTaggerProvider.TrackingSession.<DetermineIfRenamableIdentifierAsync>d__20.MoveNext()

Looks to be the same issue. I'll take a look.

[mavasani]

I have a consistent repro now:

1. Git clone roslyn-analyzers git repo and checkout the sources from 8th May
2. cibuild - to build the repo
3. Open src\Analyzers.sln
4. Open file: \src\Microsoft.QualityGuidelines.Analyzers\Core\UseLiteralsWhereAppropriate.cs
5. Go to line 73 and delete all text after 'fieldInitializerValue.Type' on that line in the if condition, including the && operator.
6. Enter '.SpecialType ==' after 'fieldInitializerValue.Type' and hit space - you should hit this crash

[mavasani]

Can we also consider making Rename tracking diagnostic configurable, so that it can be disabled if the user doesn't care about this feature?

[jmarolf]

@mavasani 's repro steps uncover a different crash. Filed as #11193

[jmarolf]

So here's whats happening:

public static SymbolKey GetSymbolKey(this ISymbol symbol)
{
    return SymbolKey.Create(symbol, null, CancellationToken.None);
}

We call symbol.GetSymbolKey() which calls SymbolKey.Create passing in a null compilation.

internal static SymbolKey Create(ISymbol symbol, CancellationToken cancellationToken = default(CancellationToken))
{
    return GetOrCreate(symbol, new Visitor(compilation, cancellationToken));
}

We create a new visitor object with a null compilation. Normally this would be the end of it but we crash due to this null compilation later.

private static SymbolKey GetOrCreate(ISymbol symbol, Visitor visitor)
{
    if (symbol == null)
    {
        return s_null;
    }

    SymbolKey result;
    if (!visitor.SymbolCache.TryGetValue(symbol, out result))
    {
>>      result = symbol.Accept(visitor);
        visitor.SymbolCache[symbol] = result;
    }

    return result;
}

The call to Accept will cause the visitor to be exercised. We jump through the visit methods until we arrive at

public override SymbolKey VisitLocal(ILocalSymbol localSymbol)
{
>>  return new NonDeclarationSymbolKey<ILocalSymbol>(localSymbol, this);
}

Which calls Enumerate Symbols

internal NonDeclarationSymbolKey(TSymbol symbol, Visitor visitor)
{
    var containingSymbol = symbol.ContainingSymbol;

    while (!containingSymbol.DeclaringSyntaxReferences.Any())
    {
        containingSymbol = containingSymbol.ContainingSymbol;
    }

    _containingKey = GetOrCreate(containingSymbol, visitor);
    _localName = symbol.Name;

>>  foreach (var possibleSymbol in EnumerateSymbols(visitor.Compilation, containingSymbol, _localName, visitor.CancellationToken))
    {
        if (possibleSymbol.Item1.Equals(symbol))
        {
            _ordinal = possibleSymbol.Item2;
            break;
        }
    }
}

In this case because of the visitation pattern we end up calling EnumerateSymbols and passing in a null compilation.
This will always crash if we end of visiting a local as part of creating a SymbolKey

[mavasani]

@jmarolf I have consistent repro for this now, and I verified that this time the exception is NRE from Microsoft.CodeAnalysis.SymbolKey.NonDeclarationSymbolKey

1. Checkout Roslyn code from my PR: Ensure that we suppress compilation diagnostics reported in generated… #11225 (commit 6f90c89) - I hope to merge this PR soon, so you may be able to skip this step.
2. Open Roslyn.sln and wait for solution load to complete.
3. Open file src/Compilers/Core/Portable/DiagnosticAnalyzer/AnalyzerDriver.cs and close all other documents.
4. Goto line 657:
   (if (!_lazyGeneratedCodeSymbolsMap.TryGetValue(tree, out existingGeneratedCodeSymbols)))
5. Save All and close the solution. Restart VS and open Roslyn.sln again - wait for solution load to complete.
6. Put the cursor at the end of existingGeneratedCodeSymbols, line 657, column 101 and type any character - you should hit this crash.