Check if parameter reference is inside expression tree (fix #902) (RC…

…S1231)
dotnet · May 26, 2022 · e0c64de · e0c64de
1 parent 54c9b66
commit e0c64de
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Showing 2 changed files with 25 additions and 1 deletion.
diff --git a/src/Analyzers/CSharp/Analysis/RefReadOnlyParameterAnalyzer.cs b/src/Analyzers/CSharp/Analysis/RefReadOnlyParameterAnalyzer.cs
@@ -272,7 +272,8 @@ public override void VisitIdentifierName(IdentifierNameSyntax node)
                     && SymbolEqualityComparer.Default.Equals(parameterSymbol, SemanticModel.GetSymbol(node, CancellationToken)))
                 {
                     if (_localFunctionDepth > 0
-                        || _anonymousFunctionDepth > 0)
+                        || _anonymousFunctionDepth > 0
+                        || node.IsInExpressionTree(SemanticModel, CancellationToken))
                     {
                         Parameters.Remove(name);
                     }

diff --git a/src/Tests/Analyzers.Tests/RCS1231MakeParameterRefReadOnlyTests.cs b/src/Tests/Analyzers.Tests/RCS1231MakeParameterRefReadOnlyTests.cs
@@ -177,6 +177,29 @@ void M(bool value)
     {
     }
 }
+");
+        }
+
+        [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.MakeParameterRefReadOnly)]
+        public async Task TestNoDiagnostic_ExpressionTree()
+        {
+            await VerifyNoDiagnosticAsync(@"
+using System;
+using System.Linq;
+
+class C
+{
+    public void M(DateTime dt)
+    {
+        var items = default(IQueryable<C>);
+
+        var x = from item in items
+            where item.P <= dt
+            select item;
+    }
+
+    public DateTime P { get; set; }
+}
 ");
         }
     }