Fix LINQ chain diagnostics (#287)

Author: marinasundstrom

CHANGELOG.md

@@ -8,6 +8,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Fixed
+
+- PR [#287](https://github.com/marinasundstrom/CheckedExceptions/pull/287) Fix LINQ chain diagnostics
+
 ## [2.1.2] - 2025-08-22
 
 ### Added

CheckedExceptions.Tests/CheckedExceptionsAnalyzerTests.Linq.cs

@@ -104,8 +104,8 @@ await Verifier.VerifyAnalyzerAsync(test, setup: o =>
     }
 
     [Fact]
-    public async Task PassDelegateByVariable()
-    {
+    public async Task PassDelegateByVariable()
+    {
         var test = /* lang=c#-test */ """
             #nullable enable
             using System;
@@ -124,11 +124,38 @@ public async Task PassDelegateByVariable()
         var expected2 = Verifier.UnhandledException("OverflowException")
             .WithSpan(9, 22, 9, 27);
 
-        await Verifier.VerifyAnalyzerAsync(test, setup: o =>
-        {
-            o.ExpectedDiagnostics.AddRange(expected, expected2);
-        }, executable: true);
-    }
+        await Verifier.VerifyAnalyzerAsync(test, setup: o =>
+        {
+            o.ExpectedDiagnostics.AddRange(expected, expected2);
+        }, executable: true);
+    }
+
+    [Fact]
+    public async Task PassDelegateByVariable_Chained()
+    {
+        var test = /* lang=c#-test */ """
+            #nullable enable
+            using System;
+            using System.Collections.Generic;
+            using System.Linq;
+
+            IEnumerable<int> items = [];
+            Func<int, bool> pred = [Throws(typeof(FormatException), typeof(OverflowException))] (z) => int.Parse("10") == z;
+            var query = items.Where(pred).Where(x => x is 0);
+            foreach (var item in query) { }
+            """;
+
+        var expected = Verifier.UnhandledException("FormatException")
+            .WithSpan(9, 22, 9, 27);
+
+        var expected2 = Verifier.UnhandledException("OverflowException")
+            .WithSpan(9, 22, 9, 27);
+
+        await Verifier.VerifyAnalyzerAsync(test, setup: o =>
+        {
+            o.ExpectedDiagnostics.AddRange(expected, expected2);
+        }, executable: true);
+    }
 
     [Fact]
     public async Task CastOperator()
@@ -156,17 +183,11 @@ public async Task CastOperator()
         var expected3 = Verifier.UnhandledException("InvalidCastException")
             .WithSpan(11, 22, 11, 27);
 
-        var expected4 = Verifier.UnhandledException("FormatException")
-            .WithSpan(8, 6, 8, 94);
-
-        var expected5 = Verifier.UnhandledException("OverflowException")
-            .WithSpan(8, 6, 8, 94);
-
-        await Verifier.VerifyAnalyzerAsync(test, setup: o =>
-        {
-            o.ExpectedDiagnostics.AddRange(expected, expected2, expected3, expected4, expected5);
-        }, executable: true);
-    }
+        await Verifier.VerifyAnalyzerAsync(test, setup: o =>
+        {
+            o.ExpectedDiagnostics.AddRange(expected, expected2, expected3);
+        }, executable: true);
+    }
 
     [Fact]
     public async Task QueryAsArgument()

CheckedExceptions/CheckedExceptionsAnalyzer.Linq.cs

@@ -28,6 +28,15 @@ private static void CollectLinqExceptions(
 
         if (!isTerminal)
         {
+            // If this invocation is the source in a chained LINQ call (e.g., xs.Where(...).Where(...)),
+            // defer handling until the outermost call is analyzed.
+            if (invocationSyntax.Parent is MemberAccessExpressionSyntax { Parent: InvocationExpressionSyntax outer } &&
+                semanticModel.GetOperation(outer, ct) is IInvocationOperation outerOp &&
+                IsLinqExtension(outerOp.TargetMethod))
+            {
+                return;
+            }
+
             // Deferred invocation inside an argument/return is handled at the boundary.
             if (invocationSyntax.FirstAncestorOrSelf<ReturnStatementSyntax>() is not null)
                 return;