From b0a64e65d6c53b525a65b46ce9fce084b5ce5da7 Mon Sep 17 00:00:00 2001
From: Timur Kelman <Timur.Kelman@fecher.eu>
Date: Fri, 8 Dec 2023 12:06:01 +0100
Subject: [PATCH] add a workaround

It's only required until https://github.com/dotnet/roslyn/issues/71115 is fixed.
---
 CodeConverter/CSharp/CommonConversions.cs     |  2 +-
 .../CSharp/DataFlowAnalysisExtensions.cs      | 24 +++++++++++++++++++
 .../CSharp/DefiniteAssignmentAnalyzer.cs      |  2 +-
 3 files changed, 26 insertions(+), 2 deletions(-)
 create mode 100644 CodeConverter/CSharp/DataFlowAnalysisExtensions.cs

diff --git a/CodeConverter/CSharp/CommonConversions.cs b/CodeConverter/CSharp/CommonConversions.cs
index 7c5c9a2cf..f1e7229ff 100644
--- a/CodeConverter/CSharp/CommonConversions.cs
+++ b/CodeConverter/CSharp/CommonConversions.cs
@@ -598,7 +598,7 @@ public CSSyntax.IdentifierNameSyntax GetRetVariableNameOrNull(VBSyntax.MethodBlo
             var flow = SemanticModel.AnalyzeDataFlow(node.Statements.First(), node.Statements.Last());
 
             if (flow.Succeeded) {
-                assignsToMethodNameVariable = flow.ReadInside.Any(equalsMethodName) || flow.WrittenInside.Any(equalsMethodName);
+                assignsToMethodNameVariable = flow.ReadInsideSafe().Any(equalsMethodName) || flow.WrittenInside.Any(equalsMethodName);
             }
         }
 
diff --git a/CodeConverter/CSharp/DataFlowAnalysisExtensions.cs b/CodeConverter/CSharp/DataFlowAnalysisExtensions.cs
new file mode 100644
index 000000000..5557ff8fa
--- /dev/null
+++ b/CodeConverter/CSharp/DataFlowAnalysisExtensions.cs
@@ -0,0 +1,24 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace ICSharpCode.CodeConverter.CSharp;
+internal static class DataFlowAnalysisExtensions
+{
+    /// <summary>
+    /// Accesses the <see cref="DataFlowAnalysis.ReadInside" /> second time in case of exception.
+    /// This is a workaround for a bug present in Roslyn up to version 4.8.0
+    /// (https://github.com/dotnet/roslyn/issues/71115)
+    /// </summary>
+    public static System.Collections.Immutable.ImmutableArray<ISymbol> ReadInsideSafe(this DataFlowAnalysis dataFlow)
+    {
+        try
+        {
+            return dataFlow.ReadInside;
+        }
+        catch
+        {
+            return dataFlow.ReadInside;
+        }
+    }
+}
diff --git a/CodeConverter/CSharp/DefiniteAssignmentAnalyzer.cs b/CodeConverter/CSharp/DefiniteAssignmentAnalyzer.cs
index 931a68ac4..66def1f57 100644
--- a/CodeConverter/CSharp/DefiniteAssignmentAnalyzer.cs
+++ b/CodeConverter/CSharp/DefiniteAssignmentAnalyzer.cs
@@ -5,7 +5,7 @@ internal static class DefiniteAssignmentAnalyzer
 
     public static bool IsDefinitelyAssignedBeforeRead(ISymbol localSymbol, DataFlowAnalysis methodFlow)
     {
-        if (!methodFlow.ReadInside.Contains(localSymbol)) return true;
+        if (!methodFlow.ReadInsideSafe().Contains(localSymbol)) return true;
         var unassignedVariables = methodFlow.GetVbUnassignedVariables();
         return unassignedVariables != null && !unassignedVariables.Contains(localSymbol, SymbolEqualityComparer.IncludeNullability);
     }