Remove unaccessible local symbols (#797)

Author: meziantou

src/Meziantou.Analyzer/Internals/OperationExtensions.cs

@@ -1,4 +1,4 @@
-using System.Collections.Generic;
+using System.Collections.Generic;
 using System.Linq;
 using System.Threading;
 using Meziantou.Analyzer.Internals;
@@ -270,6 +270,12 @@ static bool IsValid(Location location, int operationLocation, int? staticContext
 
                 if (isInInitializer)
                     continue;
+
+                // Cannot use variables declared in top-level statements when not in this context
+                if (symbol.ContainingSymbol?.IsTopLevelStatement(cancellationToken) is true && operation.GetContainingMethod(cancellationToken)?.IsTopLevelStatement(cancellationToken) is not true)
+                {
+                    continue;
+                }
             }
 
             yield return symbol;

src/Meziantou.Analyzer/Rules/UseAnOverloadThatHasCancellationTokenAnalyzer.cs

@@ -309,7 +309,6 @@ public void AnalyzeLoop(OperationAnalysisContext context)
 
         private string[] FindCancellationTokens(IOperation operation, CancellationToken cancellationToken)
         {
-
             var availableSymbols = new List<NameAndType>();
 
             foreach (var symbol in operation.LookupAvailableSymbols(cancellationToken))

tests/Meziantou.Analyzer.Test/Rules/UseAnOverloadThatHasCancellationTokenAnalyzerTests.cs

@@ -1,4 +1,4 @@
-using System.Threading.Tasks;
+using System.Threading.Tasks;
 using Meziantou.Analyzer.Rules;
 using Meziantou.Analyzer.Test.Helpers;
 using TestHelper;
@@ -1271,4 +1271,29 @@ class Sample
               .ShouldReportDiagnosticWithMessage("Use an overload with a CancellationToken, available tokens: Xunit.TestContext.Current.CancellationToken")
               .ValidateAsync();
     }
+
+    [Fact]
+    public async Task TopLevelStatements()
+    {
+        await CreateProjectBuilder()
+              .WithSourceCode("""
+                using System.Threading;
+                using System.Threading.Tasks;
+
+                var cancellationToken = CancellationToken.None;
+
+                class Sample
+                {
+                    void Foo()
+                    {
+                        {|MA0032:Repro()|};
+                    }
+
+                    public static void Repro() => throw null;
+                    public static void Repro(CancellationToken cancellationToken) => throw null;
+                }
+                """)
+              .WithOutputKind(Microsoft.CodeAnalysis.OutputKind.ConsoleApplication)
+              .ValidateAsync();
+    }
 }