feat: add support for switch expressions

Author: Meir017

Diff for: src/DendroDocs.Tool/Analyzers/BranchingAnalyzer.cs

@@ -57,6 +57,26 @@ public override void VisitSwitchStatement(SwitchStatementSyntax node)
         }
     }
 
+    public override void VisitSwitchExpression(SwitchExpressionSyntax node)
+    {
+        var switchStatement = new Switch();
+        statements.Add(switchStatement);
+
+        switchStatement.Expression = node.GoverningExpression.ToString();
+
+        foreach (var arm in node.Arms)
+        {
+            var switchSection = new SwitchSection();
+            switchStatement.Sections.Add(switchSection);
+
+            var label = $"{arm.Pattern}{(arm.WhenClause?.Condition is not null ? $" when {arm.WhenClause.Condition}" : string.Empty)}";
+            switchSection.Labels.Add(label);
+
+            var invocationAnalyzer = new InvocationsAnalyzer(semanticModel, switchSection.Statements);
+            invocationAnalyzer.Visit(arm.Expression);
+        }
+    }
+
     private static string Label(SwitchLabelSyntax label)
     {
         return label switch

Diff for: src/DendroDocs.Tool/Analyzers/InvocationsAnalyzer.cs

@@ -36,6 +36,12 @@ public override void VisitSwitchStatement(SwitchStatementSyntax node)
         branchingAnalyzer.Visit(node);
     }
 
+    public override void VisitSwitchExpression(SwitchExpressionSyntax node)
+    {
+        var branchingAnalyzer = new BranchingAnalyzer(semanticModel, statements);
+        branchingAnalyzer.Visit(node);
+    }
+
     public override void VisitIfStatement(IfStatementSyntax node)
     {
         var branchingAnalyzer = new BranchingAnalyzer(semanticModel, statements);

Diff for: tests/DendroDocs.Tool.Tests/Analyzers/BranchingAnalyzerTests.cs

@@ -79,4 +79,44 @@ private static IEnumerable<object[]> GetSwitchStatements()
         yield return new object[] { "switch (Something) { case 1 when true: break; }", 1, new[] { new[] { "1 when true" } } };
         yield return new object[] { "switch (Something) { case int value: break; }", 1, new[] { new[] { "int value" } } };
     }
+
+    [DynamicData(nameof(GetSwitchExpressions), DynamicDataSourceType.Method)]
+    [TestMethod]
+    public void ShouldParseSwitchExpressionsCorrectly(string code, int sections, string[][] conditions)
+    {
+        // Assign
+        var source = @$"
+        public class Test
+        {{
+            public int Something;
+            object Method()
+            {{
+                {code}
+            }}
+        }}
+        ";
+
+        // Act
+        var types = TestHelper.VisitSyntaxTree(source, "CS8509");
+
+        // Assert
+        types[0].Methods[0].Statements[0].Should().BeOfType<ReturnDescription>();
+        var @switch = types[0].Methods[0].Statements[1].Should().BeOfType<Switch>().Subject;
+        @switch.Sections.Should().HaveCount(sections);
+
+        for (var i = 0; i < @switch.Sections.Count; i++)
+        {
+            @switch.Sections[i].Labels.Should().Equal(conditions[i]);
+        }
+    }
+
+    private static IEnumerable<object[]> GetSwitchExpressions()
+    {
+        yield return new object[] { "return Something switch { _ => false };", 1, new[] { new[] { "_" } } };
+        yield return new object[] { "return Something switch { 1 => true };", 1, new[] { new[] { "1" } } };
+        yield return new object[] { "return Something switch { 1 or 2 => true };", 1, new[] { new[] { "1 or 2" } } };
+        yield return new object[] { "return Something switch { 1 => true, 2 => true };", 2, new[] { new[] { "1" }, new[] { "2" } } };
+        yield return new object[] { "return Something switch { 1 when true => true, _ => false };", 2, new[] { new[] { "1 when true" }, new[] { "_" } } };
+        yield return new object[] { "return Something switch { int value => false };", 1, new[] { new[] { "int value" } } };
+    }
 }