fix and test

src/Common/CSharp/Analysis/UseConstantInsteadOfFieldAnalysis.cs

@@ -2,6 +2,7 @@
 
 using System;
 using System.Diagnostics;
+using System.Linq;
 using System.Threading;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
@@ -69,7 +70,7 @@ internal static class UseConstantInsteadOfFieldAnalysis
 
         if (!fieldSymbol.Type.SupportsConstantValue())
             return false;
-
+        
         foreach (VariableDeclaratorSyntax declarator in declarators)
         {
             ExpressionSyntax value = declarator.Initializer?.Value;
@@ -82,6 +83,18 @@ internal static class UseConstantInsteadOfFieldAnalysis
 
             if (!semanticModel.HasConstantValue(value, cancellationToken))
                 return false;
+
+            // Changing a static field to a constant changes the meaning of that symbol in the declerators.
+            foreach (var identifierName in value.DescendantNodesAndSelf().OfType<IdentifierNameSyntax>())
+            {
+                if (identifierName.Identifier.ValueText != fieldSymbol.Name)
+                    continue;
+
+                if (identifierName.Parent is MemberAccessExpressionSyntax memberAccessExpression && memberAccessExpression.Name == identifierName)
+                    continue;
+
+                return false;
+            }
         }
 
         foreach (IMethodSymbol constructorSymbol in fieldSymbol.ContainingType.StaticConstructors)

src/Tests/Analyzers.Tests/RCS1187UseConstantInsteadOfFieldTests.cs

@@ -86,6 +86,19 @@ static void M(in int value)
     {
     }
 }
+");
+    }
+
+    [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.UseConstantInsteadOfField)]
+    public async Task TestNoDiagnostic_SelfReference()
+    {
+        await VerifyNoDiagnosticAsync(@"
+using System;
+
+class C
+{
+    private static readonly Double Double = Double.Epsilon; 
+}
 ");
     }
 }