Anonymous type create expressions: when all names can be inferred from the initializers, don't create NamedExpressions.

ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs

@@ -714,21 +714,40 @@ namespace ICSharpCode.Decompiler.Ast
 								return ace;
 							}
 						}
-						var oce = new Ast.ObjectCreateExpression();
 						if (declaringType.IsAnonymousType()) {
 							MethodDefinition ctor = ((MethodReference)operand).Resolve();
 							if (methodDef != null) {
-								oce.Initializer = new ArrayInitializerExpression();
+								AnonymousTypeCreateExpression atce = new AnonymousTypeCreateExpression();
+								bool allNamesCanBeInferred = true;
 								for (int i = 0; i < args.Count; i++) {
-									oce.Initializer.Elements.Add(
+									string inferredName;
-										new NamedExpression {
+									if (args[i] is IdentifierExpression)
-											Identifier = ctor.Parameters[i].Name,
+										inferredName = ((IdentifierExpression)args[i]).Identifier;
-											Expression = args[i]
+									else if (args[i] is MemberReferenceExpression)
-										});
+										inferredName = ((MemberReferenceExpression)args[i]).MemberName;
+									else
+										inferredName = null;
+									
+									if (inferredName != ctor.Parameters[i].Name) {
+										allNamesCanBeInferred = false;
+										break;
+									}
 								}
+								if (allNamesCanBeInferred) {
+									atce.Initializers.AddRange(args);
+								} else {
+									for (int i = 0; i < args.Count; i++) {
+										atce.Initializers.Add(
+											new NamedExpression {
+												Identifier = ctor.Parameters[i].Name,
+												Expression = args[i]
+											});
+									}
+								}
+								return atce;
 							}
-							return oce;
 						}
+						var oce = new Ast.ObjectCreateExpression();
 						oce.Type = AstBuilder.ConvertType(declaringType);
 						oce.Arguments.AddRange(args);
 						return oce.WithAnnotation(operand);

ICSharpCode.Decompiler/Ast/Transforms/CombineQueryExpressions.cs

@@ -78,11 +78,17 @@ namespace ICSharpCode.Decompiler.Ast.Transforms
 		}
 		
 		static readonly QuerySelectClause selectTransparentIdentifierPattern = new QuerySelectClause {
-			Expression = new ObjectCreateExpression {
+			Expression = new Choice {
-				Initializer = new ArrayInitializerExpression {
+				new AnonymousTypeCreateExpression {
-					Elements = {
+					Initializers = {
 						new NamedNode("nae1", new NamedExpression { Expression = new IdentifierExpression() }),
-						new NamedNode("nae2", new NamedExpression { Expression = new AnyNode() })
+						new NamedNode("nae2", new NamedExpression { Expression = new AnyNode("nae2Expr") })
+					}
+				},
+				new AnonymousTypeCreateExpression {
+					Initializers = {
+						new NamedNode("identifier", new IdentifierExpression()),
+						new AnyNode("nae2Expr")
 					}
 				}
 			}};
@@ -100,12 +106,13 @@ namespace ICSharpCode.Decompiler.Ast.Transforms
 			if (!match.Success)
 				return false;
 			QuerySelectClause selectClause = (QuerySelectClause)innerQuery.Clauses.Last();
-			NamedExpression nae1 = match.Get<NamedExpression>("nae1").Single();
+			NamedExpression nae1 = match.Get<NamedExpression>("nae1").SingleOrDefault();
-			NamedExpression nae2 = match.Get<NamedExpression>("nae2").Single();
+			NamedExpression nae2 = match.Get<NamedExpression>("nae2").SingleOrDefault();
-			if (nae1.Identifier != ((IdentifierExpression)nae1.Expression).Identifier)
+			if (nae1 != null && nae1.Identifier != ((IdentifierExpression)nae1.Expression).Identifier)
 				return false;
-			IdentifierExpression nae2IdentExpr = nae2.Expression as IdentifierExpression;
+			Expression nae2Expr = match.Get<Expression>("nae2Expr").Single();
-			if (nae2IdentExpr != null && nae2.Identifier == nae2IdentExpr.Identifier) {
+			IdentifierExpression nae2IdentExpr = nae2Expr as IdentifierExpression;
+			if (nae2IdentExpr != null && (nae2 == null || nae2.Identifier == nae2IdentExpr.Identifier)) {
 				// from * in (from x in ... select new { x = x, y = y }) ...
 				// =>
 				// from x in ... ...
@@ -127,7 +134,16 @@ namespace ICSharpCode.Decompiler.Ast.Transforms
 				foreach (var clause in innerQuery.Clauses) {
 					query.Clauses.InsertAfter(insertionPos, insertionPos = clause.Detach());
 				}
-				query.Clauses.InsertAfter(insertionPos, new QueryLetClause { Identifier = nae2.Identifier, Expression = nae2.Expression.Detach() });
+				string ident;
+				if (nae2 != null)
+					ident = nae2.Identifier;
+				else if (nae2Expr is IdentifierExpression)
+					ident = ((IdentifierExpression)nae2Expr).Identifier;
+				else if (nae2Expr is MemberReferenceExpression)
+					ident = ((MemberReferenceExpression)nae2Expr).MemberName;
+				else
+					throw new InvalidOperationException("Could not infer name from initializer in AnonymousTypeCreateExpression");
+				query.Clauses.InsertAfter(insertionPos, new QueryLetClause { Identifier = ident, Expression = nae2Expr.Detach() });
 			}
 			return true;
 		}

ICSharpCode.Decompiler/Tests/QueryExpressions.cs

@@ -35,7 +35,7 @@ public class QueryExpressions
 	{
 		public int OrderID;
 		public DateTime OrderDate;
-		public Customer Customer;
+		public QueryExpressions.Customer Customer;
 		public int CustomerID;
 		public decimal Total;
 		public IEnumerable<QueryExpressions.OrderDetail> Details;
@@ -54,7 +54,7 @@ public class QueryExpressions
 	{
 		return
 			from c in this.customers
-			where c.Orders.Count() > 10
+			where c.Orders.Count<QueryExpressions.Order>() > 10
 			where c.Country == "DE"
 			select c;
 	}
@@ -64,7 +64,12 @@ public class QueryExpressions
 		return
 			from c in this.customers
 			from o in c.Orders
-			select new { c.Name, o.OrderID, o.Total };
+			select new
+			{
+				c.Name,
+				o.OrderID,
+				o.Total
+			};
 	}
 	
 	public object SelectManyFollowedByOrderBy()
@@ -73,7 +78,12 @@ public class QueryExpressions
 			from c in this.customers
 			from o in c.Orders
 			orderby o.Total descending
-			select new { c.Name, o.OrderID, o.Total };
+			select new
+			{
+				c.Name,
+				o.OrderID,
+				o.Total
+			};
 	}
 	
 	public object MultipleSelectManyFollowedBySelect()
@@ -82,7 +92,12 @@ public class QueryExpressions
 			from c in this.customers
 			from o in c.Orders
 			from d in o.Details
-			select new { c.Name, o.OrderID, d.Quantity };
+			select new
+			{
+				c.Name,
+				o.OrderID,
+				d.Quantity
+			};
 	}
 	
 	public object MultipleSelectManyFollowedByLet()
@@ -92,16 +107,25 @@ public class QueryExpressions
 			from o in c.Orders
 			from d in o.Details
 			let x = d.Quantity * d.UnitPrice
-			select new { c.Name, o.OrderID, x };
+			select new
+			{
+				c.Name,
+				o.OrderID,
+				x
+			};
 	}
 	
 	public object FromLetWhereSelect()
 	{
 		return
 			from o in this.orders
-			let t = o.Details.Sum(d => d.UnitPrice * d.Quantity)
+			let t = o.Details.Sum((QueryExpressions.OrderDetail d) => d.UnitPrice * d.Quantity)
-			where t >= 1000
+			where t >= 1000m
-			select new { o.OrderID, Total = t };
+			select new
+			{
+				OrderID = o.OrderID,
+				Total = t
+			};
 	}
 	
 	public object MultipleLet()
@@ -116,25 +140,34 @@ public class QueryExpressions
 	public object Join()
 	{
 		return
-			from c in customers
+			from c in this.customers
-			join o in orders on c.CustomerID equals o.CustomerID
+			join o in this.orders on c.CustomerID equals o.CustomerID
-			select new { c.Name, o.OrderDate, o.Total };
+			select new
+			{
+				c.Name,
+				o.OrderDate,
+				o.Total
+			};
 	}
 	
 	public object JoinInto()
 	{
 		return
-			from c in customers
+			from c in this.customers
-			join o in orders on c.CustomerID equals o.CustomerID into co
+			join o in this.orders on c.CustomerID equals o.CustomerID into co
-			let n = co.Count()
+			let n = co.Count<QueryExpressions.Order>()
 			where n >= 10
-			select new { c.Name, OrderCount = n };
+			select new
+			{
+				Name = c.Name,
+				OrderCount = n
+			};
 	}
 	
 	public object OrderBy()
 	{
 		return
-			from o in orders
+			from o in this.orders
 			orderby o.Customer.Name, o.Total descending
 			select o;
 	}
@@ -142,14 +175,14 @@ public class QueryExpressions
 	public object GroupBy()
 	{
 		return
-			from c in customers
+			from c in this.customers
 			group c.Name by c.Country;
 	}
 	
 	public object ExplicitType()
 	{
 		return
-			from Customer c in customers
+			from QueryExpressions.Customer c in this.customers
 			where c.City == "London"
 			select c;
 	}
@@ -157,8 +190,12 @@ public class QueryExpressions
 	public object QueryContinuation()
 	{
 		return
-			from c in customers
+			from c in this.customers
 			group c by c.Country into g
-			select new { Country = g.Key, CustCount = g.Count() };
+			select new
+			{
+				Country = g.Key,
+				CustCount = g.Count<QueryExpressions.Customer>()
+			};
 	}
 }

ICSharpCode.Decompiler/Tests/TestRunner.cs

@@ -112,7 +112,7 @@ namespace ICSharpCode.Decompiler.Tests
 			TestFile(@"..\..\Tests\PropertiesAndEvents.cs");
 		}
 		
-		[Test, Ignore("Formatting differences in anonymous method create expressions")]
+		[Test]
 		public void QueryExpressions()
 		{
 			TestFile(@"..\..\Tests\QueryExpressions.cs");