Fix ElementAt suggestion with field reference (#68)

* Fix ElementAt suggestion with field reference
* Fix copy and paste error in NumericTests

Author: cbersch

src/AwesomeAssertions.Analyzers.Tests/Tips/CollectionTests.cs

@@ -846,20 +846,22 @@ public void CollectionShouldHaveElementAt_AccessPropertyOfIndexedValue_TestNoAna
             DiagnosticVerifier.VerifyCSharpDiagnosticUsingAllAnalyzers(GenerateCode.GenericIListCodeBlockAssertion(assertion));
 
         [TestMethod]
+        [DataRow("List<Value>")]
+        [DataRow("Value[]")]
         [Implemented]
-        public void CollectionShouldHaveElementAt_AccessObjectPropertyOfIndexedValue_TestNoAnalyzer()
+        public void CollectionShouldHaveElementAt_AccessObjectPropertyOfIndexedValue_TestNoAnalyzer(string collectionType)
         {
             // I cannot see the relevant difference to CollectionShouldHaveElementAt_AccessPropertyOfIndexedValue_TestNoAnalyzer,
             // but it makes a difference.
-            string source = """
+            string source = $$"""
                 using System.Collections.Generic;
                 using AwesomeAssertions;
 
                 public record Value(object InstanceValue);
 
                 public sealed class TestClass
                 {
-                    public void TestMethod(List<Value> list)
+                    public void TestMethod({{collectionType}} list)
                     {
                         list[0].InstanceValue.Should().Be(1);
                     }
@@ -868,6 +870,29 @@ public void TestMethod(List<Value> list)
             DiagnosticVerifier.VerifyCSharpDiagnosticUsingAllAnalyzers(source);
         }
 
+        [TestMethod]
+        [DataRow("List<Value>")]
+        [DataRow("Value[]")]
+        [Implemented]
+        public void CollectionShouldHaveElementAt_AccessObjectFieldOfIndexedValue_TestNoAnalyzer(string collectionType)
+        {
+            string source = $$"""
+                using System.Collections.Generic;
+                using AwesomeAssertions;
+
+                using Value = System.ValueTuple<object>;
+
+                public sealed class TestClass
+                {
+                    public void TestMethod({{collectionType}} list)
+                    {
+                        list[0].Item1.Should().Be(1);
+                    }
+                }
+                """;
+            DiagnosticVerifier.VerifyCSharpDiagnosticUsingAllAnalyzers(source);
+        }
+
         [TestMethod]
         [Implemented]
         public void CollectionShouldHaveElementAt_ClassDoesNotImplementIList_TestNoAnalyzer()

src/AwesomeAssertions.Analyzers.Tests/Tips/NumericTests.cs

@@ -53,7 +53,7 @@ public class NumericTests
 
         [TestMethod]
         [DataRow("actual.Should().BeLessThanOrEqualTo(upper, \"because reason 1\").And.BeGreaterThanOrEqualTo(lower, \"because reason 2\");")]
-        [DataRow("actual.Should().BeLessThanOrEqualTo(upper, \"because reason 1\").And.BeGreaterThanOrEqualTo(lower, \"because reason 2\");")]
+        [DataRow("actual.Should().BeGreaterThanOrEqualTo(lower, \"because reason 1\").And.BeLessThanOrEqualTo(upper, \"because reason 2\");")]
         [Implemented]
         public void NumericShouldBeInRange_BeLessThanOrEqualToAndBeGreaterThanOrEqualTo_WithMessagesInBothAssertions_TestAnalyzer(string assertion)
         {

src/AwesomeAssertions.Analyzers/Tips/AwesomeAssertionsAnalyzer.cs

@@ -388,16 +388,12 @@ private static void AnalyzeInvocation(OperationAnalysisContext context, AwesomeA
                         }
                     }
 
-                    if (subject.TryGetSingleChildOrSelf<IPropertyReferenceOperation>(out var propertyReference) && !propertyReference.Property.IsIndexer)
-                    {
-                        return;
-                    }
-                    else if (subject.TryGetFirstDescendent<IArrayElementReferenceOperation>(out _))
-                    {
-                        context.ReportDiagnostic(CreateDiagnostic(assertion, DiagnosticMetadata.CollectionShouldHaveElementAt_IndexerShouldBe));
-                    }
-                    else if (subject.TryGetFirstDescendentOrSelf(out propertyReference) && propertyReference.Property.IsIndexer && 
-                        (propertyReference.Instance.Type.ImplementsOrIsInterface(metadata.IListOfT) || propertyReference.Instance.Type.ImplementsOrIsInterface(metadata.IReadonlyListOfT)))
+                    subject = subject.UnwrapConversion();
+
+                    bool isListIndexer = subject is IPropertyReferenceOperation propertyReference && propertyReference.Property.IsIndexer &&
+                        (propertyReference.Instance.Type.ImplementsOrIsInterface(metadata.IListOfT) || propertyReference.Instance.Type.ImplementsOrIsInterface(metadata.IReadonlyListOfT));
+
+                    if (subject is IArrayElementReferenceOperation || isListIndexer)
                     {
                         context.ReportDiagnostic(CreateDiagnostic(assertion, DiagnosticMetadata.CollectionShouldHaveElementAt_IndexerShouldBe));
                     }

src/AwesomeAssertions.Analyzers/Utilities/OperationExtensions.cs

@@ -7,49 +7,6 @@ namespace AwesomeAssertions.Analyzers;
 
 internal static class OperationExtensions
 {
-    /// <summary>
-    /// Tries to get the parent operation or its first child if it's of the requested type.
-    /// <typeparamref name="TOperation"/>.
-    /// </summary>
-    public static bool TryGetSingleChildOrSelf<TOperation>(this IOperation parent, out TOperation operation) where TOperation : IOperation
-    {
-        if (parent is TOperation op)
-        {
-            operation = op;
-            return true;
-        }
-        return parent.TryGetSingleChild(out operation);
-    }
-
-    /// <summary>
-    /// Tries to get the first child of the parent operation if it's of the requested type
-    /// <typeparamref name="TOperation"/>.
-    /// </summary>
-    public static bool TryGetSingleChild<TOperation>(this IOperation parent, out TOperation operation) where TOperation : IOperation
-    {
-        if (parent.ChildOperations.Count == 1 && parent.ChildOperations.First() is TOperation op)
-        {
-            operation = op;
-            return true;
-        }
-
-        operation = default;
-        return false;
-    }
-
-    /// <summary>
-    /// Tries to get the first descendent of the parent operation or the parent operation itself. where each operation has only one child.
-    /// </summary>
-    public static bool TryGetFirstDescendentOrSelf<TOperation>(this IOperation parent, out TOperation operation) where TOperation : IOperation
-    {
-        if (parent is TOperation op)
-        {
-            operation = op;
-            return true;
-        }
-        return parent.TryGetFirstDescendent(out operation);
-    }
-
     /// <summary>
     /// Tries to get the first descendent of the parent operation. where each operation has only one child.
     /// </summary>