Enhancement to EFCore analyzer

Vogen.sln.DotSettings

@@ -31,6 +31,7 @@
 	<s:String x:Key="/Default/CodeStyle/CodeFormatting/CSharpCodeStyle/ARGUMENTS_LITERAL/@EntryValue">Named</s:String>
 	<s:Boolean x:Key="/Default/CodeStyle/CodeFormatting/CSharpFormat/WRAP_AFTER_INVOCATION_LPAR/@EntryValue">True</s:Boolean>
 	<s:String x:Key="/Default/CodeStyle/CodeFormatting/CSharpFormat/WRAP_ARGUMENTS_STYLE/@EntryValue">CHOP_IF_LONG</s:String>
+	<s:String x:Key="/Default/CodeStyle/CSharpVarKeywordUsage/ForOtherTypes/@EntryValue">UseVarWhenEvident</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/PredefinedNamingRules/=PrivateConstants/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="_" Suffix="" Style="aaBb" /&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/PredefinedNamingRules/=PrivateStaticReadonly/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="_" Suffix="" Style="aaBb" /&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/UserRules/=15b5b1f1_002D457c_002D4ca6_002Db278_002D5615aedc07d3/@EntryIndexedValue">&lt;Policy&gt;&lt;Descriptor Staticness="Static" AccessRightKinds="Private" Description="Static readonly fields (private)"&gt;&lt;ElementKinds&gt;&lt;Kind Name="READONLY_FIELD" /&gt;&lt;/ElementKinds&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" Prefix="_" Suffix="" Style="aaBb" /&gt;&lt;/Policy&gt;</s:String>

src/Vogen/Rules/DoNotCompareWithPrimitivesInEfCoreAnalyzer.cs

@@ -11,7 +11,8 @@ namespace Vogen.Rules;
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
 public class DoNotCompareWithPrimitivesInEfCoreAnalyzer : DiagnosticAnalyzer
 {
-    private static readonly ImmutableHashSet<string> _knownNames = new[] { "Where", "Single", "SkipWhile", "TakeWhile", "Select" }.ToImmutableHashSet();
+    private static readonly ImmutableHashSet<string> _knownNames =
+        new[] { "Where", "Single", "SkipWhile", "TakeWhile", "Select" }.ToImmutableHashSet();
 
     // ReSharper disable once ArrangeObjectCreationWhenTypeEvident - current bug in Roslyn analyzer means it
     // won't find this and will report:
@@ -36,46 +37,62 @@ public override void Initialize(AnalysisContext context)
         context.EnableConcurrentExecution();
 
         context.RegisterSyntaxNodeAction(AnalyzeInvocation, SyntaxKind.InvocationExpression);
-        context.RegisterSyntaxNodeAction(AnalyzeQieryExpression, SyntaxKind.QueryExpression);
+        context.RegisterSyntaxNodeAction(AnalyzeQueryExpression, SyntaxKind.QueryExpression);
     }
 
     private static void AnalyzeInvocation(SyntaxNodeAnalysisContext context)
     {
         var invocationExpr = (InvocationExpressionSyntax) context.Node;
-        if (invocationExpr.Expression is not MemberAccessExpressionSyntax memberAccessExpr) return;
+        if (invocationExpr.Expression is not MemberAccessExpressionSyntax memberAccessExpr)
+        {
+            return;
+        }
 
         if (!_knownNames.Contains(memberAccessExpr.Name.Identifier.Text))
         {
             return;
         }
 
-        if (!IsAMemberOfDbSet(context, memberAccessExpr.Expression)) return;
+        ExpressionSyntax expressionSyntax = memberAccessExpr.Expression;
+
+        if (!IsAMemberOfDbSet(context, expressionSyntax))
+        {
+            return;
+        }
 
-        foreach (ArgumentSyntax eachArgument in invocationExpr.ArgumentList.Arguments.Where(e => e.Expression is LambdaExpressionSyntax))
+        foreach (ArgumentSyntax eachArgument in
+                 invocationExpr.ArgumentList.Arguments.Where(e => e.Expression is LambdaExpressionSyntax))
         {
             foreach (BinaryExpressionSyntax eachBinaryExpression in eachArgument.DescendantNodes().OfType<BinaryExpressionSyntax>())
             {
                 ITypeSymbol? left = context.SemanticModel.GetTypeInfo(eachBinaryExpression.Left).Type;
                 ITypeSymbol? right = context.SemanticModel.GetTypeInfo(eachBinaryExpression.Right).Type;
 
-                if (left is null || right is null) continue;
+                if (left is null || right is null)
+                {
+                    continue;
+                }
 
                 // Check if left is ValueObject and right is integer
                 if (IsValueObject(left) && right.SpecialType == SpecialType.System_Int32)
                 {
-                    context.ReportDiagnostic(DiagnosticsCatalogue.BuildDiagnostic(_rule, left.Name, eachBinaryExpression.GetLocation()));
+                    context.ReportDiagnostic(
+                        DiagnosticsCatalogue.BuildDiagnostic(_rule, left.Name, eachBinaryExpression.GetLocation()));
                 }
             }
         }
     }
 
-    private static void AnalyzeQieryExpression(SyntaxNodeAnalysisContext context)
+    private static void AnalyzeQueryExpression(SyntaxNodeAnalysisContext context)
     {
         var queryExpr = (QueryExpressionSyntax) context.Node;
         var whereClauses = queryExpr.Body.DescendantNodes().OfType<WhereClauseSyntax>();
         var fromClause = queryExpr.FromClause;
 
-        if (!IsAMemberOfDbSet(context, fromClause.Expression)) return;
+        if (!IsAMemberOfDbSet(context, fromClause.Expression))
+        {
+            return;
+        }
 
         foreach (var eachArgument in whereClauses)
         {
@@ -84,12 +101,16 @@ private static void AnalyzeQieryExpression(SyntaxNodeAnalysisContext context)
                 ITypeSymbol? left = context.SemanticModel.GetTypeInfo(eachBinaryExpression.Left).Type;
                 ITypeSymbol? right = context.SemanticModel.GetTypeInfo(eachBinaryExpression.Right).Type;
 
-                if (left is null || right is null) continue;
+                if (left is null || right is null)
+                {
+                    continue;
+                }
 
                 // Check if left is ValueObject and right is integer
                 if (IsValueObject(left) && right.SpecialType == SpecialType.System_Int32)
                 {
-                    context.ReportDiagnostic(DiagnosticsCatalogue.BuildDiagnostic(_rule, left.Name, eachBinaryExpression.GetLocation()));
+                    context.ReportDiagnostic(
+                        DiagnosticsCatalogue.BuildDiagnostic(_rule, left.Name, eachBinaryExpression.GetLocation()));
                 }
             }
         }
@@ -99,20 +120,44 @@ private static bool IsAMemberOfDbSet(SyntaxNodeAnalysisContext context, Expressi
     {
         var symbolInfo = context.SemanticModel.GetSymbolInfo(expressionSyntax);
 
-        if (symbolInfo.Symbol is not IPropertySymbol ps) return false;
+        ITypeSymbol? typeSymbol = null;
+
+        if (symbolInfo.Symbol is IPropertySymbol ps)
+        {
+            typeSymbol = ps.Type;
+        }
+
+        if (symbolInfo.Symbol is ILocalSymbol ls)
+        {
+            typeSymbol = ls.Type;
+        }
+
+        if (typeSymbol is null)
+        {
+            return false;
+        }
 
         var dbSetType = context.SemanticModel.Compilation.GetTypeByMetadataName("Microsoft.EntityFrameworkCore.DbSet`1");
-
-        if (dbSetType is null) return false;
 
-        return InheritsFrom(ps.Type, dbSetType);
+        if (dbSetType is null)
+        {
+            return false;
+        }
+
+        return InheritsFrom(typeSymbol, dbSetType);
     }
 
-    private static bool IsValueObject(ITypeSymbol type) => 
+
+    private static bool IsValueObject(ITypeSymbol type) =>
         type is INamedTypeSymbol symbol && VoFilter.IsTarget(symbol);
 
-    private static bool InheritsFrom(ITypeSymbol? type, INamedTypeSymbol baseType)
+    private static bool InheritsFrom(ITypeSymbol? type, INamedTypeSymbol? baseType)
     {
+        if (baseType is null)
+        {
+            return false;
+        }
+
         while (type != null)
         {
             if (SymbolEqualityComparer.Default.Equals(type.OriginalDefinition, baseType))

src/Vogen/Vogen.csproj

@@ -61,6 +61,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" PrivateAssets="all"/>
+    <PackageReference Include="Microsoft.CodeAnalysis.AnalyzerUtilities" Version="3.3.4" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp" PrivateAssets="all" />
   </ItemGroup>
 

tests/AnalyzerTests/DoNotCompareWithPrimitivesInEfCoreAnalyzerTests.cs

@@ -104,6 +104,53 @@ await Run(
                 WithDiagnostics("VOG034", DiagnosticSeverity.Error, "Age", 0));
         }
 
+        [Fact]
+        public async Task Triggers_when_found_in_IQueryableOfDbSet_in_separate_expression()
+        {
+            var source = _source + """
+
+                                   public static class Test
+                                   {
+                                       public static void FilterItems()
+                                       {
+                                           using var ctx = new DbContext();
+                                           
+                                           DbSet<EmployeeEntity> step1 = ctx.Entities;
+                                           var entities = step1.Where(e => {|#0:e.Age == 50|});
+                                       }
+                                   }
+                                   """;
+            var sources = await CombineUserAndGeneratedSource(source);
+
+            await Run(
+                sources,
+                WithDiagnostics("VOG034", DiagnosticSeverity.Error, "Age", 0));
+        }
+
+        [Fact(Skip = "It would be nice if this did work, but I couldn't get it working. Please see the thread at https://github.com/SteveDunn/Vogen/issues/684")]
+        public async Task Triggers_when_found_in_IQueryableOfDbSet_in_separate_expression_twice_removed()
+        {
+            var source = _source + """
+
+                                   public static class Test
+                                   {
+                                       public static void FilterItems()
+                                       {
+                                           using var ctx = new DbContext();
+                                           
+                                           DbSet<EmployeeEntity> step1 = ctx.Entities;
+                                           var step2 = step1.Take(4);
+                                           var entities = step2.Where(e => {|#0:e.Age == 50|});
+                                       }
+                                   }
+                                   """;
+            var sources = await CombineUserAndGeneratedSource(source);
+
+            await Run(
+                sources,
+                WithDiagnostics("VOG034", DiagnosticSeverity.Error, "Age", 0));
+        }
+
         [Fact]
         public async Task Triggers_when_found_using_query_syntax()
         {

tests/Testbench/EfCoreTest/EfCoreScenario.cs

@@ -0,0 +1,75 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Query.Internal;
+
+namespace Vogen.EfCoreTest;
+
+public static class EfCoreScenario
+{
+    public static void Run()
+    {
+        using var context = new MyContext();
+        //context.Database.Migrate();
+
+        AddAndSaveItems(amount: 10);
+        AddAndSaveItems(amount: 10);
+
+        PrintItems();
+
+        FilterItems();
+
+        return;
+
+        static void AddAndSaveItems(int amount)
+        {
+            using var context = new MyContext();
+
+            for (int i = 0; i < amount; i++)
+            {
+                var entity = new EmployeeEntity
+                {
+                    Name = Name.From("Fred #" + i),
+                    Age = Age.From(42 + i),
+                    Department = Department.From("Quarry"),
+                    HireDate = HireDate.From(new DateOnly(1066, 12, 13))
+                };
+
+                context.Entities.Add(entity);
+            }
+
+            context.SaveChanges();
+        }
+
+        static void PrintItems()
+        {
+            using var ctx = new MyContext();
+
+            var entities = ctx.Entities.ToList();
+            Console.WriteLine(string.Join(Environment.NewLine, entities.Select(e => $"ID: {e.Id.Value}, Name: {e.Name}, Age: {e.Age}")));
+        }
+
+        static void FilterItems()
+        {
+            Console.WriteLine();
+            Console.WriteLine("FILTERING ITEMS...");
+            using var ctx = new MyContext();
+
+            int age = 50;
+            // var entities = from e in ctx.Entities where e != null && e.Age == age select e;
+            // var entities2 = ctx.Entities.Where(e => e != null && e.Age == age);
+
+            DbSet<EmployeeEntity> step1 = ctx.Entities;
+            //IQueryable<EmployeeEntity> step2 = step1.Take(4);
+            var step3 = step1.Where(e => e.Age == age);
+
+
+
+//            Console.WriteLine(string.Join(Environment.NewLine, entities.Select(e => $"ID: {e.Id.Value}, Name: {e.Name}, Age: {e.Age}")));
+
+        }
+    }
+
+}