Fix S1117 FP: Local variables declared in static context (#8937)

analyzers/its/expected/Nancy/S1117-Nancy-net452.json

@@ -1,40 +1,10 @@
 {
   "Issues": [
-    {
-      "Id": "S1117",
-      "Message": "Rename \u0027assemblies\u0027 which hides the field with the same name.",
-      "Uri": "https://github.com/SonarSource/sonar-dotnet/blob/master/analyzers/its/sources/Nancy/src/Nancy/AppDomainAssemblyCatalog.cs#L32",
-      "Location": "Line 32 Position 17-27"
-    },
-    {
-      "Id": "S1117",
-      "Message": "Rename \u0027assemblies\u0027 which hides the field with the same name.",
-      "Uri": "https://github.com/SonarSource/sonar-dotnet/blob/master/analyzers/its/sources/Nancy/src/Nancy/AppDomainAssemblyCatalog.cs#L41",
-      "Location": "Line 41 Position 17-27"
-    },
-    {
-      "Id": "S1117",
-      "Message": "Rename \u0027assemblies\u0027 which hides the field with the same name.",
-      "Uri": "https://github.com/SonarSource/sonar-dotnet/blob/master/analyzers/its/sources/Nancy/src/Nancy/AppDomainAssemblyCatalog.cs#L56",
-      "Location": "Line 56 Position 17-27"
-    },
     {
       "Id": "S1117",
       "Message": "Rename \u0027parameters\u0027 which hides the field with the same name.",
       "Uri": "https://github.com/SonarSource/sonar-dotnet/blob/master/analyzers/its/sources/Nancy/src/Nancy/HttpLink.cs#L230",
       "Location": "Line 230 Position 17-27"
-    },
-    {
-      "Id": "S1117",
-      "Message": "Rename \u0027prefix\u0027 which hides the field with the same name.",
-      "Uri": "https://github.com/SonarSource/sonar-dotnet/blob/master/analyzers/its/sources/Nancy/src/Nancy/HttpLinkRelation.cs#L152",
-      "Location": "Line 152 Position 21-27"
-    },
-    {
-      "Id": "S1117",
-      "Message": "Rename \u0027value\u0027 which hides the field with the same name.",
-      "Uri": "https://github.com/SonarSource/sonar-dotnet/blob/master/analyzers/its/sources/Nancy/src/Nancy/HttpLinkRelation.cs#L153",
-      "Location": "Line 153 Position 21-26"
     }
   ]
 }

analyzers/its/expected/Nancy/S1117-Nancy-netstandard2.0.json

@@ -5,18 +5,6 @@
       "Message": "Rename \u0027parameters\u0027 which hides the field with the same name.",
       "Uri": "https://github.com/SonarSource/sonar-dotnet/blob/master/analyzers/its/sources/Nancy/src/Nancy/HttpLink.cs#L230",
       "Location": "Line 230 Position 17-27"
-    },
-    {
-      "Id": "S1117",
-      "Message": "Rename \u0027prefix\u0027 which hides the field with the same name.",
-      "Uri": "https://github.com/SonarSource/sonar-dotnet/blob/master/analyzers/its/sources/Nancy/src/Nancy/HttpLinkRelation.cs#L152",
-      "Location": "Line 152 Position 21-27"
-    },
-    {
-      "Id": "S1117",
-      "Message": "Rename \u0027value\u0027 which hides the field with the same name.",
-      "Uri": "https://github.com/SonarSource/sonar-dotnet/blob/master/analyzers/its/sources/Nancy/src/Nancy/HttpLinkRelation.cs#L153",
-      "Location": "Line 153 Position 21-26"
     }
   ]
 }

analyzers/src/SonarAnalyzer.CSharp/Rules/VariableShadowsField.cs

@@ -90,7 +90,8 @@ private static List<ISymbol> GetContextSymbols(SonarSyntaxNodeReportingContext c
 
         private static void ReportOnVariableMatchingField(SonarSyntaxNodeReportingContext context, IEnumerable<ISymbol> members, SyntaxToken identifier)
         {
-            if (members.FirstOrDefault(x => x.Name == identifier.ValueText) is { } matchingMember)
+            if (members.FirstOrDefault(x => x.Name == identifier.ValueText
+                && (x.IsStatic || !identifier.Parent.EnclosingScope().GetModifiers().Any(x => x.Kind() == SyntaxKind.StaticKeyword))) is { } matchingMember)
             {
                 context.ReportIssue(Diagnostic.Create(Rule, identifier.GetLocation(), identifier.Text, GetSymbolName(matchingMember)));
             }

analyzers/tests/SonarAnalyzer.Test/TestCases/VariableShadowsField.CSharp12.cs

@@ -37,18 +37,13 @@ void MyMethod()
 // Reproducer for https://github.com/SonarSource/sonar-dotnet/issues/8260
 class Repro_8260(int primaryCtorParam)
 {
-    private int instanceField = 1;
-    private int instanceProperty { get; set; } = 1;
-    private static int staticField = 1;
-    private static int staticProperty = 1;
-
     public static void StaticMethod()
     {
-        var instanceField = 2; // Noncompliant FP (instance field is not accessible from static method)
-        var instanceProperty = 2; // Noncompliant FP (instance property is not accessible from static method)
-        var primaryCtorParam = 2; // Noncompliant FP (primary ctor parameter is not accessible from static method)
+        var primaryCtorParam = 42;      // Compliant (primary ctor parameter is not accessible from static method)
+    }
 
-        var staticField = 2; // Noncompliant
-        var staticProperty = 2; // Noncompliant
+    public void NonStaticMethod()
+    {
+        var primaryCtorParam = 42;      // Noncompliant
     }
 }

analyzers/tests/SonarAnalyzer.Test/TestCases/VariableShadowsField.cs

@@ -159,4 +159,59 @@ public void OutParameter(out object parameter)
             parameter = null;
         }
     }
+
+    public class Base
+    {
+        private int privateInstanceField = 1;
+        private int privateInstanceProperty { get; set; } = 1;
+        private static int privateStaticField = 1;
+        private static int privateStaticProperty = 1;
+
+        protected int protectedInstanceField = 1;
+        protected int protectedInstanceProperty { get; set; } = 1;
+        protected static int protectedStaticField = 1;
+        protected static int protectedStaticProperty = 1;
+
+        public static void BaseStaticMethod()
+        {
+            var privateInstanceField = 2;       // Compliant (instance field is not accessible from static method)
+            var privateInstanceProperty = 2;    // Compliant (instance property is not accessible from static method)
+
+            var privateStaticField = 2;         // Noncompliant
+            var privateStaticProperty = 2;      // Noncompliant
+        }
+
+        public void BaseInstanceMethod()
+        {
+            var privateInstanceField = 2;       // Noncompliant
+            var privateInstanceProperty = 2;    // Noncompliant
+
+            var privateStaticField = 2;         // Noncompliant
+            var privateStaticProperty = 2;      // Noncompliant
+        }
+    }
+
+    public class Derived : Base
+    {
+        public static void DerivedStaticMethod()
+        {
+            var privateStaticField = 2;         // Compliant (private field from the base class is not accessible in the derived class)
+            var privateStaticProperty = 2;      // Compliant (private property from the base class is not accessible in the derived class)
+
+            var protectedInstanceField = 2;     // Compliant (instance field is not accessible from static method)
+            var protectedInstanceProperty = 2;  // Compliant (instance property is not accessible from static method)
+
+            var protectedStaticField = 2;       // FN - members from the base class are not checked
+            var protectedStaticProperty = 2;    // FN
+        }
+
+        public void DerivedInstanceMethod()
+        {
+            var protectedInstanceField = 2;     // FN
+            var protectedInstanceProperty = 2;  // FN
+
+            var protectedStaticField = 2;       // FN
+            var protectedStaticProperty = 2;    // FN
+        }
+    }
 }