feat: support proprties of objects (#211)

* reproduce flow with failing test

* reproduce flow with failing test

* reproduce flow with failing test

* feat: support assertions on property of object

* feat: support assertions on property of object

* revert rename refactoring

Author: Meir017

src/FluentAssertions.Analyzers.Tests/Tips/SanityTests.cs

@@ -1,8 +1,5 @@
 using FluentAssertions.Analyzers.Xunit;
 using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.CSharp;
-using Microsoft.CodeAnalysis.CSharp.Syntax;
-using Microsoft.CodeAnalysis.Text;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 
 namespace FluentAssertions.Analyzers.Tests
@@ -314,5 +311,48 @@ public static void True(bool input)
                 Locations = new[] { new DiagnosticResultLocation("Test0.cs", 7, 9) }
             });
         }
+
+        [TestMethod]
+        [Implemented(Reason = "https://github.com/fluentassertions/fluentassertions.analyzers/issues/207")]
+        public void PropertiesOfTypes()
+        {
+            const string source = @"
+using Xunit;
+using FluentAssertions;
+using FluentAssertions.Extensions;
+using System.Collections.Generic;
+using System.Linq;
+public class TestClass
+{
+    public static void Main()
+    {
+        var x = new TestType1();
+        x.Prop1.Prop2.List.Any().Should().BeTrue();
+        x.Prop1.Prop2.Count.Should().BeGreaterThan(10);
+    }
+}
+
+public class TestType1
+{
+    public TestType2 Prop1 { get; set; }
+}
+public class TestType2
+{
+    public TestType3 Prop2 { get; set; }
+}
+public class TestType3
+{
+    public List<int> List { get; set; }
+    public int Count { get; set; }
+}";
+
+            DiagnosticVerifier.VerifyCSharpDiagnosticUsingAllAnalyzers(new[] { source }, new DiagnosticResult()
+            {
+                Id = CollectionShouldNotBeEmptyAnalyzer.DiagnosticId,
+                Message = CollectionShouldNotBeEmptyAnalyzer.Message,
+                Severity = DiagnosticSeverity.Info,
+                Locations = new[] { new DiagnosticResultLocation("Test0.cs", 12, 9) }
+            });
+        }
     }
 }

src/FluentAssertions.Analyzers/Utilities/FluentAssertionsAnalyzer.cs

@@ -62,9 +62,11 @@ protected virtual Diagnostic AnalyzeExpression(ExpressionSyntax expression, Sema
             var variableNameExtractor = new VariableNameExtractor(semanticModel);
             expression.Accept(variableNameExtractor);
 
-            if (variableNameExtractor.VariableIdentifierName == null) return null;
-            var typeInfo = semanticModel.GetTypeInfo(variableNameExtractor.VariableIdentifierName);
-            if (!ShouldAnalyzeVariableTypeCore(typeInfo.Type, semanticModel)) return null;
+            if (variableNameExtractor.PropertiesAccessed
+                .ConvertAll(identifier => semanticModel.GetTypeInfo(identifier))
+                .TrueForAll(typeInfo => !ShouldAnalyzeVariableTypeCore(typeInfo.Type, semanticModel))) {
+                return null;
+            }
 
             foreach (var visitor in Visitors)
             {

src/FluentAssertions.Analyzers/Utilities/VariableNameExtractor.cs

@@ -1,15 +1,18 @@
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis;
+using System.Collections.Generic;
 
 namespace FluentAssertions.Analyzers
 {
     public class VariableNameExtractor : CSharpSyntaxWalker
     {
         private readonly SemanticModel _semanticModel;
 
-        public string VariableName { get; private set; }
-        public IdentifierNameSyntax VariableIdentifierName { get; private set; }
+        public string VariableName => VariableIdentifierName?.Identifier.Text;
+        public IdentifierNameSyntax VariableIdentifierName => PropertiesAccessed.Count > 0 ? PropertiesAccessed[0] : null;
+
+        public List<IdentifierNameSyntax> PropertiesAccessed { get; } = new List<IdentifierNameSyntax>();
 
         public VariableNameExtractor(SemanticModel semanticModel = null)
         {
@@ -20,17 +23,7 @@ public override void VisitIdentifierName(IdentifierNameSyntax node)
         {
             if (IsVariable(node))
             {
-                VariableName = node.Identifier.Text;
-                VariableIdentifierName = node;
-            }
-        }
-
-        public override void Visit(SyntaxNode node)
-        {
-            // the first identifier encountered will be the one at the bottom of the syntax tree
-            if (VariableName == null)
-            {
-                base.Visit(node);
+                PropertiesAccessed.Add(node);
             }
         }