Compilation of this example with VS in .net8 hanging

[Kozinaka]

.NET 8.0
VisualStudio.17.Release/17.14.13+36414.22.-august.2025-
Microsoft .NET Framework
Version 4.8.09037
Installed Version: Professional
C# Tools 4.14.0-3.25412.6+c167adef821b9ba2f1c44c227a5e79ca11876461

My test project compiles successfully in net6, but in net8 it causes the Roslyn analyzer and compilation to hang.

To reproduce:

1. Open solution from attached source-code: Net8CodeAnalysisHangingExample.zip
2. Start solution building

Expected Behavior: Successful solution build.

Actual Behavior: Compilation hanging.

[CyrusNajmabadi]

Looks to be a hang in 'points-to' analysis:

The line (groupLeft, groupRight) = (groupRight, groupLeft); is likely causing an infinite loop due to the swapping of variables. I have no idea how points-to is supposed to work. So someone with more knowledge will likely need to look into this.

Callstack:

Microsoft.CodeAnalysis.NetAnalyzers.dll!Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.AnalysisEntityDataFlowOperationVisitor<Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisData, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisContext, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisResult, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAbstractValue>.TransferValueTypeInstanceAnalysisDataForAssignment(Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.AnalysisEntity targetAnalysisEntity, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.AnalysisEntity valueAnalysisEntity, Microsoft.CodeAnalysis.IOperation assignedValueOperation) Line 306	C#
 	Microsoft.CodeAnalysis.NetAnalyzers.dll!Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.AnalysisEntityDataFlowOperationVisitor<Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisData, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisContext, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisResult, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAbstractValue>.SetAbstractValueForAssignment(Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.AnalysisEntity targetAnalysisEntity, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.AnalysisEntity assignedValueEntity, Microsoft.CodeAnalysis.IOperation assignedValueOperation, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAbstractValue assignedValue) Line 222	C#
 	Microsoft.CodeAnalysis.NetAnalyzers.dll!Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.AnalysisEntityDataFlowOperationVisitor<Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisData, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisContext, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisResult, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAbstractValue>.HandleDeconstructionAssignment(Microsoft.CodeAnalysis.IOperation target, System.Collections.Immutable.ImmutableHashSet<Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.AnalysisEntity> childEntities) Line 659	C#
 	Microsoft.CodeAnalysis.NetAnalyzers.dll!Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.AnalysisEntityDataFlowOperationVisitor<Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisData, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisContext, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisResult, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAbstractValue>.VisitDeconstructionAssignment(Microsoft.CodeAnalysis.Operations.IDeconstructionAssignmentOperation operation, object argument) Line 632	C#
>	Microsoft.CodeAnalysis.dll!Microsoft.CodeAnalysis.Operations.DeconstructionAssignmentOperation.Accept<object, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAbstractValue>(Microsoft.CodeAnalysis.Operations.OperationVisitor<object, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAbstractValue> visitor, object argument) Line 7426	C#
 	Microsoft.CodeAnalysis.NetAnalyzers.dll!Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.DataFlowOperationVisitor<Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisData, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisContext, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisResult, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAbstractValue>.VisitCore(Microsoft.CodeAnalysis.IOperation operation, object argument) Line 2162	C#
 	Microsoft.CodeAnalysis.NetAnalyzers.dll!Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.DataFlowOperationVisitor<Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisData, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisContext, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisResult, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAbstractValue>.Visit(Microsoft.CodeAnalysis.IOperation operation, object argument) Line 2120	C#
 	Microsoft.CodeAnalysis.NetAnalyzers.dll!Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.DataFlowOperationVisitor<Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisData, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisContext, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisResult, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAbstractValue>.VisitArray(System.Collections.Generic.IEnumerable<Microsoft.CodeAnalysis.IOperation> operations, object argument) Line 2111	C#
 	Microsoft.CodeAnalysis.NetAnalyzers.dll!Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysis.PointsToDataFlowOperationVisitor.DefaultVisit(Microsoft.CodeAnalysis.IOperation operation, object argument) Line 879	C#
 	Microsoft.CodeAnalysis.dll!Microsoft.CodeAnalysis.Operations.OperationVisitor<object, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAbstractValue>.VisitExpressionStatement(Microsoft.CodeAnalysis.Operations.IExpressionStatementOperation operation, object argument) Line 11569	C#
 	Microsoft.CodeAnalysis.dll!Microsoft.CodeAnalysis.Operations.ExpressionStatementOperation.Accept<object, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAbstractValue>(Microsoft.CodeAnalysis.Operations.OperationVisitor<object, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAbstractValue> visitor, object argument) Line 4914	C#
 	Microsoft.CodeAnalysis.NetAnalyzers.dll!Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.DataFlowOperationVisitor<Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisData, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisContext, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisResult, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAbstractValue>.VisitCore(Microsoft.CodeAnalysis.IOperation operation, object argument) Line 2162	C#
 	Microsoft.CodeAnalysis.NetAnalyzers.dll!Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.DataFlowOperationVisitor<Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisData, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisContext, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisResult, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAbstractValue>.Visit(Microsoft.CodeAnalysis.IOperation operation, object argument) Line 2120	C#
 	Microsoft.CodeAnalysis.NetAnalyzers.dll!Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysis.PointsToDataFlowOperationVisitor.Flow(Microsoft.CodeAnalysis.IOperation statement, Microsoft.CodeAnalysis.FlowAnalysis.BasicBlock block, Microsoft.CodeAnalysis.FlowAnalysis.DataFlow.PointsToAnalysis.PointsToAnalysisData input) Line 372	C#

[Kozinaka]

The hang resolves with any of these actions:

1. Remove AssemblyInfo.cs from the LibA project
2. Move all .cs sources to LibB
3. Remove any part of the code around the commented line

[jjonescz]

Looks like the problem is inside Microsoft.CodeAnalysis.NetAnalyzers which lives in the sdk repo, I will move this issue there.