Merge pull request #40281 from dotnet/merges/release/dev16.4-to-release/dev16.4-vs-deps

Merge release/dev16.4 to release/dev16.4-vs-deps

src/Compilers/CSharp/Portable/FlowAnalysis/NullableWalker.cs

@@ -3607,7 +3607,7 @@ protected override void VisitArguments(ImmutableArray<BoundExpression> arguments
                 }
             }
 
-            if (method is object && (method.FlowAnalysisAnnotations & FlowAnalysisAnnotations.DoesNotReturn) == FlowAnalysisAnnotations.DoesNotReturn)
+            if (!IsAnalyzingAttribute && method is object && (method.FlowAnalysisAnnotations & FlowAnalysisAnnotations.DoesNotReturn) == FlowAnalysisAnnotations.DoesNotReturn)
             {
                 SetUnreachable();
             }

src/Compilers/CSharp/Test/Semantic/Semantics/NullableReferenceTypesTests.cs

@@ -7235,6 +7235,31 @@ class C { }
                 );
         }
 
+        [Fact, WorkItem(40136, "https://github.com/dotnet/roslyn/issues/40136")]
+        public void SelfReferencingAttribute()
+        {
+            var source = @"
+using System;
+
+[AttributeUsage(AttributeTargets.All)]
+[ExplicitCrossPackageInternal(ExplicitCrossPackageInternalAttribute.s)]
+internal sealed class ExplicitCrossPackageInternalAttribute : Attribute
+{
+    internal const string s = """";
+
+    [ExplicitCrossPackageInternal(s)]
+    internal ExplicitCrossPackageInternalAttribute([ExplicitCrossPackageInternal(s)] string prop)
+    {
+    }
+
+    [return: ExplicitCrossPackageInternal(s)]
+    [ExplicitCrossPackageInternal(s)]
+    internal void Method() { }
+}";
+            var comp = CreateNullableCompilation(source);
+            comp.VerifyDiagnostics();
+        }
+
         [Fact]
         public void NullableAndConditionalOperators()
         {