Do not mark BoundBlock associated with ArrowExpressionClause as compiler...

Do not mark BoundBlock associated with ArrowExpressionClause as compiler generated. This ensures SemanticModel does proper caching for this node. (changeset 1362639)

Src/Compilers/CSharp/Portable/Binder/Binder_Statements.cs

@@ -3220,7 +3220,7 @@ private static bool IsValidStatementExpression(CSharpSyntaxNode syntax, BoundExp
             }
 
             // Need to attach the tree for when we generate sequence points.
-            return new BoundBlock(node, locals, ImmutableArray.Create(statement)) { WasCompilerGenerated = true };
+            return new BoundBlock(node, locals, ImmutableArray.Create(statement)) { WasCompilerGenerated = node.Kind != SyntaxKind.ArrowExpressionClause };
         }
 
         /// <summary>

Src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_Block.cs

@@ -11,7 +11,7 @@ internal sealed partial class LocalRewriter
     {
         public override BoundNode VisitBlock(BoundBlock node)
         {
-            if (node.WasCompilerGenerated || !this.GenerateDebugInfo)
+            if (node.WasCompilerGenerated || !this.GenerateDebugInfo || node.Syntax.Kind == SyntaxKind.ArrowExpressionClause)
             {
                 return node.Update(node.Locals, VisitList(node.Statements));
             }

Src/Compilers/CSharp/Test/Semantic/Semantics/ExpressionBodiedMemberTests.cs

@@ -3,6 +3,7 @@
 using Microsoft.CodeAnalysis.CSharp.Test.Utilities;
 using Microsoft.CodeAnalysis.CSharp.UnitTests;
 using Roslyn.Test.Utilities;
+using System.Linq;
 using Xunit;
 
 namespace Microsoft.CodeAnalysis.CSharp.Semantic.UnitTests.Semantics
@@ -304,5 +305,27 @@ static void Main()
 
             CompileAndVerify(source, expectedOutput: "GetAction 1");
         }
+
+        [Fact, WorkItem(1069421, "DevDiv")]
+        public void Bug1069421()
+        {
+            var comp = CreateCompilationWithMscorlib45(@"
+class Program
+{
+    private int x => () => { 
+}
+");
+
+            var tree = comp.SyntaxTrees[0];
+            var model = comp.GetSemanticModel(tree);
+
+            var node = tree.GetRoot().DescendantNodes().OfType<ParenthesizedLambdaExpressionSyntax>().Single();
+
+            var typeInfo1 = model.GetTypeInfo(node);
+            var typeInfo2 = model.GetTypeInfo(node);
+
+            Assert.Equal(typeInfo1.Type, typeInfo2.Type);
+        }
+
     }
 }