Unexpected value 'FunctionType' of type 'Microsoft.CodeAnalysis.CSharp.ConversionKind' in .NET 6 RC1 (works in .NET 5.0)

**Version Used**: .NET 6 RC1

**Steps to Reproduce**:

1. Attempt to compile the following code:
```c#
using System.Linq.Expressions;
using System.Reflection;

public class Program
{
    public static void Main()
    {
        SomeMethod((Employee e) => e.Name);
    }

    public static void SomeMethod(Field field) { }

    public class Employee
    {
        public string Name {  get; set; }
    }

    public class Field
    {
        public static implicit operator Field(Expression expression) => null;
    }
}
```

**Expected Behavior**:
Builds without blowing up the csc compiler as it does in .NET 5.0

**Actual Behavior**:

```
Rebuild started...
1>------ Rebuild All started: Project: ConsoleApp1, Configuration: Debug Any CPU ------
Restored D:\Projects\ConsoleApp1\ConsoleApp1\ConsoleApp1.csproj (in 1 ms).
1>You are using a preview version of .NET. See: https://aka.ms/dotnet-core-preview
1>C:\Program Files\Microsoft Visual Studio\2022\Preview\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(75,5): error MSB6006: "csc.exe" exited with code -2146232797.
1>Done building project "ConsoleApp1.csproj" -- FAILED.
========== Rebuild All: 0 succeeded, 1 failed, 0 skipped ==========
```

![image](https://user-images.githubusercontent.com/282584/133381737-f5dad1e9-9857-4789-a6ce-ca86901e1bd4.png)

```
StreamJsonRpc.RemoteInvocationException: Unexpected value 'FunctionType' of type 'Microsoft.CodeAnalysis.CSharp.ConversionKind'
   at StreamJsonRpc.JsonRpc.<InvokeCoreAsync>d__139`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.CodeAnalysis.Remote.BrokeredServiceConnection`1.<TryInvokeAsync>d__16`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception exceptionObject)
RPC server exception:
System.InvalidOperationException: Unexpected value 'FunctionType' of type 'Microsoft.CodeAnalysis.CSharp.ConversionKind'
      at Microsoft.CodeAnalysis.CSharp.ConversionsBase.IsEncompassingImplicitConversionKind(ConversionKind kind)
      at Microsoft.CodeAnalysis.CSharp.ConversionsBase.<ComputeApplicableUserDefinedImplicitConversionSet>g__addCandidatesFromType|136_0(TypeParameterSymbol constrainedToTypeOpt, NamedTypeSymbol declaringType, BoundExpression sourceExpression, TypeSymbol source, TypeSymbol target, ArrayBuilder`1 u, CompoundUseSiteInfo`1& useSiteInfo, Boolean allowAnyTarget)
      at Microsoft.CodeAnalysis.CSharp.ConversionsBase.ComputeApplicableUserDefinedImplicitConversionSet(BoundExpression sourceExpression, TypeSymbol source, TypeSymbol target, ArrayBuilder`1 d, ArrayBuilder`1 u, CompoundUseSiteInfo`1& useSiteInfo, Boolean allowAnyTarget)
      at Microsoft.CodeAnalysis.CSharp.ConversionsBase.AnalyzeImplicitUserDefinedConversions(BoundExpression sourceExpression, TypeSymbol source, TypeSymbol target, CompoundUseSiteInfo`1& useSiteInfo)
      at Microsoft.CodeAnalysis.CSharp.ConversionsBase.ClassifyImplicitConversionFromExpression(BoundExpression sourceExpression, TypeSymbol destination, CompoundUseSiteInfo`1& useSiteInfo)
      at Microsoft.CodeAnalysis.CSharp.OverloadResolution.CheckArgumentForApplicability(Symbol candidate, BoundExpression argument, RefKind argRefKind, TypeSymbol parameterType, RefKind parRefKind, Boolean ignoreOpenTypes, CompoundUseSiteInfo`1& useSiteInfo, Boolean forExtensionMethodThisArg, Boolean hasInterpolatedStringRefMismatch)
      at Microsoft.CodeAnalysis.CSharp.OverloadResolution.IsApplicable(Symbol candidate, EffectiveParameters parameters, AnalyzedArguments arguments, ImmutableArray`1 argsToParameters, Boolean isVararg, Boolean hasAnyRefOmittedArgument, Boolean ignoreOpenTypes, Boolean completeResults, CompoundUseSiteInfo`1& useSiteInfo)
      at Microsoft.CodeAnalysis.CSharp.OverloadResolution.IsApplicable[TMember](TMember member, TMember leastOverriddenMember, ArrayBuilder`1 typeArgumentsBuilder, AnalyzedArguments arguments, EffectiveParameters originalEffectiveParameters, EffectiveParameters constructedEffectiveParameters, ImmutableArray`1 argsToParamsMap, Boolean hasAnyRefOmittedArgument, Boolean inferWithDynamic, Boolean completeResults, CompoundUseSiteInfo`1& useSiteInfo)
      at Microsoft.CodeAnalysis.CSharp.OverloadResolution.IsMemberApplicableInNormalForm[TMember](TMember member, TMember leastOverriddenMember, ArrayBuilder`1 typeArguments, AnalyzedArguments arguments, Boolean isMethodGroupConversion, Boolean allowRefOmittedArguments, Boolean inferWithDynamic, Boolean completeResults, CompoundUseSiteInfo`1& useSiteInfo)
      at Microsoft.CodeAnalysis.CSharp.OverloadResolution.AddMemberToCandidateSet[TMember](TMember member, ArrayBuilder`1 results, ArrayBuilder`1 members, ArrayBuilder`1 typeArguments, BoundExpression receiverOpt, AnalyzedArguments arguments, Boolean completeResults, Boolean isMethodGroupConversion, Boolean allowRefOmittedArguments, Dictionary`2 containingTypeMapOpt, Boolean inferWithDynamic, CompoundUseSiteInfo`1& useSiteInfo, Boolean allowUnexpandedForm)
      at Microsoft.CodeAnalysis.CSharp.OverloadResolution.PerformMemberOverloadResolution[TMember](ArrayBuilder`1 results, ArrayBuilder`1 members, ArrayBuilder`1 typeArguments, BoundExpression receiver, AnalyzedArguments arguments, Boolean completeResults, Boolean isMethodGroupConversion, RefKind returnRefKind, TypeSymbol returnType, Boolean allowRefOmittedArguments, Boolean isFunctionPointerResolution, CallingConventionInfo& callingConventionInfo, CompoundUseSiteInfo`1& useSiteInfo, Boolean inferWithDynamic, Boolean allowUnexpandedForm)
      at Microsoft.CodeAnalysis.CSharp.Binder.ResolveDefaultMethodGroup(BoundMethodGroup node, AnalyzedArguments analyzedArguments, Boolean isMethodGroupConversion, CompoundUseSiteInfo`1& useSiteInfo, Boolean inferWithDynamic, Boolean allowUnexpandedForm, RefKind returnRefKind, TypeSymbol returnType, Boolean isFunctionPointerResolution, CallingConventionInfo& callingConvention)
      at Microsoft.CodeAnalysis.CSharp.Binder.ResolveMethodGroupInternal(BoundMethodGroup methodGroup, SyntaxNode expression, String methodName, AnalyzedArguments analyzedArguments, Boolean isMethodGroupConversion, CompoundUseSiteInfo`1& useSiteInfo, Boolean inferWithDynamic, Boolean allowUnexpandedForm, RefKind returnRefKind, TypeSymbol returnType, Boolean isFunctionPointerResolution, CallingConventionInfo& callingConvention)
      at Microsoft.CodeAnalysis.CSharp.Binder.ResolveMethodGroup(BoundMethodGroup node, SyntaxNode expression, String methodName, AnalyzedArguments analyzedArguments, Boolean isMethodGroupConversion, CompoundUseSiteInfo`1& useSiteInfo, Boolean inferWithDynamic, Boolean allowUnexpandedForm, RefKind returnRefKind, TypeSymbol returnType, Boolean isFunctionPointerResolution, CallingConventionInfo& callingConventionInfo)
      at Microsoft.CodeAnalysis.CSharp.Binder.BindMethodGroupInvocation(SyntaxNode syntax, SyntaxNode expression, String methodName, BoundMethodGroup methodGroup, AnalyzedArguments analyzedArguments, BindingDiagnosticBag diagnostics, CSharpSyntaxNode queryClause, Boolean allowUnexpandedForm, Boolean& anyApplicableCandidates)
      at Microsoft.CodeAnalysis.CSharp.Binder.BindInvocationExpression(SyntaxNode node, SyntaxNode expression, String methodName, BoundExpression boundExpression, AnalyzedArguments analyzedArguments, BindingDiagnosticBag diagnostics, CSharpSyntaxNode queryClause, Boolean allowUnexpandedForm)
      at Microsoft.CodeAnalysis.CSharp.Binder.BindInvocationExpression(InvocationExpressionSyntax node, BindingDiagnosticBag diagnostics)
      at Microsoft.CodeAnalysis.CSharp.Binder.BindExpressionInternal(ExpressionSyntax node, BindingDiagnosticBag diagnostics, Boolean invoked, Boolean indexed)
      at Microsoft.CodeAnalysis.CSharp.Binder.BindExpression(ExpressionSyntax node, BindingDiagnosticBag diagnostics, Boolean invoked, Boolean indexed)
      at Microsoft.CodeAnalysis.CSharp.Binder.BindExpressionStatement(CSharpSyntaxNode node, ExpressionSyntax syntax, Boolean allowsAnyExpression, BindingDiagnosticBag diagnostics)
      at Microsoft.CodeAnalysis.CSharp.Binder.BindStatement(StatementSyntax node, BindingDiagnosticBag diagnostics)
      at Microsoft.CodeAnalysis.CSharp.Binder.BindSimpleProgramCompilationUnit(CompilationUnitSyntax compilationUnit, SynthesizedSimpleProgramEntryPointSymbol simpleProgram, BindingDiagnosticBag diagnostics)
      at Microsoft.CodeAnalysis.CSharp.MemberSemanticModel.EnsureNullabilityAnalysisPerformedIfNecessary()
      at Microsoft.CodeAnalysis.CSharp.MemberSemanticModel.GetRemappedSymbol[T](T originalSymbol)
      at Microsoft.CodeAnalysis.CSharp.MemberSemanticModel.GetDeclaredLocalFunction(LocalFunctionStatementSyntax declarationSyntax)
      at Microsoft.CodeAnalysis.CSharp.MemberSemanticModel.GetDeclaredSymbol(LocalFunctionStatementSyntax declarationSyntax, CancellationToken cancellationToken)
      at Microsoft.CodeAnalysis.CSharp.SyntaxTreeSemanticModel.GetDeclaredSymbol(LocalFunctionStatementSyntax declarationSyntax, CancellationToken cancellationToken)
      at Microsoft.CodeAnalysis.CSharp.CSharpSemanticModel.GetDeclaredSymbolCore(SyntaxNode node, CancellationToken cancellationToken)
      at Microsoft.CodeAnalysis.CSharp.CSharpSemanticModel.GetDeclaredSymbolsCore(SyntaxNode declaration, CancellationToken cancellationToken)
      at Microsoft.CodeAnalysis.Diagnostics.SuppressMessageAttributeState.IsDiagnosticSuppressed(Diagnostic diagnostic, SuppressMessageInfo& info)
      at Microsoft.CodeAnalysis.Diagnostics.SuppressMessageAttributeState.ApplySourceSuppressions(Diagnostic diagnostic)
      at Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver.FilterDiagnosticsSuppressedInSource(ImmutableArray`1 diagnostics, Compilation compilation, SuppressMessageAttributeState suppressMessageState)
      at Microsoft.CodeAnalysis.Diagnostics.AnalysisResultBuilder.ApplySuppressionsAndStoreAnalysisResult(AnalysisScope analysisScope, AnalyzerDriver driver, Compilation compilation, Func`2 getAnalyzerActionCounts, Boolean fullAnalysisResultForAnalyzersInScope)
      at Microsoft.CodeAnalysis.Diagnostics.CompilationWithAnalyzers.<ComputeAnalyzerDiagnosticsCoreAsync>d__72.MoveNext()
   --- End of stack trace from previous location where exception was thrown ---
      at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
      at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception exceptionObject)
   --- End of stack trace from previous location where exception was thrown ---
      at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
      at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
      at Microsoft.CodeAnalysis.Diagnostics.CompilationWithAnalyzers.<>c__DisplayClass67_1.<<ComputeAnalyzerDiagnosticsAsync>b__1>d.MoveNext()
   --- End of stack trace from previous location where exception was thrown ---
      at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
      at Microsoft.CodeAnalysis.Diagnostics.CompilationWithAnalyzers.<ComputeAnalyzerDiagnosticsAsync>d__67.MoveNext()
   --- End of stack trace from previous location where exception was thrown ---
      at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
      at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
      at Microsoft.CodeAnalysis.Diagnostics.CompilationWithAnalyzers.<ComputeAnalyzerSyntaxDiagnosticsAsync>d__59.MoveNext()
   --- End of stack trace from previous location where exception was thrown ---
      at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
      at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
      at Microsoft.CodeAnalysis.Diagnostics.CompilationWithAnalyzers.<GetAnalysisResultCoreAsync>d__57.MoveNext()
   --- End of stack trace from previous location where exception was thrown ---
      at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
      at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
      at Microsoft.CodeAnalysis.Diagnostics.Extensions.<GetAnalysisResultAsync>d__12.MoveNext()
   --- End of stack trace from previous location where exception was thrown ---
      at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
      at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
      at Microsoft.CodeAnalysis.Diagnostics.Extensions.<GetAnalysisResultAsync>d__11.MoveNext()
   --- End of stack trace from previous location where exception was thrown ---
      at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
      at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
      at Microsoft.CodeAnalysis.Remote.Diagnostics.DiagnosticComputer.<AnalyzeAsync>d__9.MoveNext()
   --- End of stack trace from previous location where exception was thrown ---
      at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
      at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
      at Microsoft.CodeAnalysis.Remote.Diagnostics.DiagnosticComputer.<GetDiagnosticsAsync>d__8.MoveNext()
   --- End of stack trace from previous location where exception was thrown ---
      at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
      at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
      at Microsoft.CodeAnalysis.Remote.RemoteDiagnosticAnalyzerService.<>c__DisplayClass3_0.<<CalculateDiagnosticsAsync>b__0>d.MoveNext()
   --- End of stack trace from previous location where exception was thrown ---
      at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
      at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
      at Microsoft.CodeAnalysis.Remote.BrokeredServiceBase.<RunServiceImplAsync>d__12`1.MoveNext()
   --- End of stack trace from previous location where exception was thrown ---
      at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
      at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception exceptionObject)
```

Relates to test plan #52192

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Unexpected value 'FunctionType' of type 'Microsoft.CodeAnalysis.CSharp.ConversionKind' in .NET 6 RC1 (works in .NET 5.0) #56407

Metadata

Assignees

Labels

Type

Fields

Projects

Milestone

Relationships

Development

Unexpected value 'FunctionType' of type 'Microsoft.CodeAnalysis.CSharp.ConversionKind' in .NET 6 RC1 (works in .NET 5.0) #56407

Description

Metadata

Metadata

Assignees

Labels

Type

Fields

Projects

Milestone

Relationships

Development

Issue actions