Fix RCS1235

ChangeLog.md

@@ -23,6 +23,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fix ([RCS1077](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1077.md)) ([#1023](https://github.com/josefpihrt/roslynator/pull/1023)).
 - Fix ([RCS1097](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1097.md)) ([#1037](https://github.com/JosefPihrt/Roslynator/pull/1037)).
 - Do not report ([RCS1170](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1170.md)) when `Microsoft.AspNetCore.Components.InjectAttribute` is used ([#1046](https://github.com/JosefPihrt/Roslynator/pull/1046)).
+- Fix ([RCS1235](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1235.md)) ([#1047](https://github.com/JosefPihrt/Roslynator/pull/1047)).
 
 ## [4.2.0] - 2022-11-27
 

src/Analyzers/CSharp/Analysis/OptimizeMethodCallAnalysis.cs

@@ -9,6 +9,7 @@
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.Diagnostics;
 using Roslynator.CSharp.Syntax;
+using Roslynator.CSharp.SyntaxWalkers;
 
 namespace Roslynator.CSharp.Analysis;
 
@@ -357,11 +358,27 @@ public static void OptimizeAdd(SyntaxNodeAnalysisContext context, in SimpleMembe
                         && (block is null
                             || SyntaxTriviaAnalysis.IsExteriorTriviaEmptyOrWhitespace(block.OpenBraceToken)))
                     {
-                        DiagnosticHelpers.ReportDiagnostic(
-                            context,
-                            DiagnosticRules.OptimizeMethodCall,
-                            invocationInfo.Name,
-                            "Add");
+                        var forEachVariableSymbol = context.SemanticModel.GetDeclaredSymbol(forEachStatement, context.CancellationToken) as ILocalSymbol;
+
+                        if (forEachVariableSymbol is not null)
+                        {
+                            ContainsLocalOrParameterReferenceWalker walker = ContainsLocalOrParameterReferenceWalker.GetInstance(forEachVariableSymbol, context.SemanticModel, context.CancellationToken);
+
+                            walker.Visit(invocationInfo.Expression);
+
+                            bool containsReference = walker.Result;
+
+                            ContainsLocalOrParameterReferenceWalker.Free(walker);
+
+                            if (!containsReference)
+                            {
+                                DiagnosticHelpers.ReportDiagnostic(
+                                    context,
+                                    DiagnosticRules.OptimizeMethodCall,
+                                    invocationInfo.Name,
+                                    "Add");
+                            }
+                        }
 
                         break;
                     }

src/Tests/Analyzers.Tests/RCS1235OptimizeMethodCallTests.cs

@@ -601,6 +601,30 @@ void M()
         string s = string.Join(""x"", new object[] { """" });
     }
 }
+");
+    }
+
+    [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.OptimizeMethodCall)]
+    public async Task TestNoDiagnostic_ForEachVariableUsedInExpression()
+    {
+        await VerifyNoDiagnosticAsync(@"
+using System.Collections.Generic;
+
+class C
+{
+    (List<int>, List<int>) M(List<int> list)
+    {
+        var positive = new List<int>();
+        var negative = new List<int>();
+
+        foreach (int i in list)
+        {
+            ((i >= 0) ? positive : negative).Add(i);
+        }
+
+        return (positive, negative);
+    }
+}
 ");
     }
 }