Fix RCS1187 (#1150)

Co-authored-by: Josef Pihrt <josef@pihrt.net>

ChangeLog.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- Fix [RCS1187](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1187.md) ([#1150](https://github.com/JosefPihrt/Roslynator/pull/1150)).
 - Fix [RCS1056](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1056.md) ([#1154](https://github.com/JosefPihrt/Roslynator/pull/1154)).
 
 ## [4.4.0] - 2023-08-01

src/Common/CSharp/Analysis/UseConstantInsteadOfFieldAnalysis.cs

@@ -82,6 +82,21 @@ 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 decorators.
+            foreach (SyntaxNode node in value.DescendantNodesAndSelf())
+            {
+                if (node is not IdentifierNameSyntax identifierName)
+                    continue;
+
+                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; 
+}
 ");
     }
 }