Improve expression debugging

* Add [DebuggerDisplay] to non-SqlExpressions too (OrderingExpression,
  ProjectionExpression).
* For SelectExpression, show the SQL in [DebuggerDisplay] and add a
  DebugView for long/short versions; this is easier than manually
  calling ExpressionPrinter in the debugger.

src/EFCore.Relational/Query/SqlExpressions/OrderingExpression.cs

@@ -12,6 +12,9 @@ namespace Microsoft.EntityFrameworkCore.Query.SqlExpressions;
 ///         not used in application code.
 ///     </para>
 /// </summary>
+#if DEBUG
+[DebuggerDisplay("{Microsoft.EntityFrameworkCore.Query.ExpressionPrinter.Print(this), nq}")]
+#endif
 public class OrderingExpression : Expression, IPrintableExpression
 {
     /// <summary>

src/EFCore.Relational/Query/SqlExpressions/ProjectionExpression.cs

@@ -12,6 +12,9 @@ namespace Microsoft.EntityFrameworkCore.Query.SqlExpressions;
 ///     application or provider, then please file an issue at
 ///     <see href="https://github.com/dotnet/efcore">github.com/dotnet/efcore</see>.
 /// </remarks>
+#if DEBUG
+[DebuggerDisplay("{Microsoft.EntityFrameworkCore.Query.ExpressionPrinter.Print(this), nq}")]
+#endif
 public sealed class ProjectionExpression : Expression, IPrintableExpression
 {
     internal ProjectionExpression(SqlExpression expression, string alias)
@@ -57,6 +60,7 @@ public ProjectionExpression Update(SqlExpression expression)
     void IPrintableExpression.Print(ExpressionPrinter expressionPrinter)
     {
         expressionPrinter.Visit(Expression);
+
         if (Alias != string.Empty
             && !(Expression is ColumnExpression column
                 && column.Name == Alias))

src/EFCore.Relational/Query/SqlExpressions/SelectExpression.cs

@@ -21,6 +21,7 @@ namespace Microsoft.EntityFrameworkCore.Query.SqlExpressions;
 ///     an issue at <see href="https://github.com/dotnet/efcore">github.com/dotnet/efcore</see>.
 /// </remarks>
 // Class is sealed because there are no public/protected constructors. Can be unsealed if this is changed.
+[DebuggerDisplay("{PrintShortSql(), nq}")]
 public sealed partial class SelectExpression : TableExpressionBase
 {
     private const string DiscriminatorColumnAlias = "Discriminator";
@@ -4561,6 +4562,13 @@ public override IEnumerable<IAnnotation> GetAnnotations()
 
     /// <inheritdoc />
     protected override void Print(ExpressionPrinter expressionPrinter)
+    {
+        PrintProjections(expressionPrinter);
+        expressionPrinter.AppendLine();
+        PrintSql(expressionPrinter);
+    }
+
+    private void PrintProjections(ExpressionPrinter expressionPrinter)
     {
         if (_clientProjections.Count > 0)
         {
@@ -4588,12 +4596,16 @@ protected override void Print(ExpressionPrinter expressionPrinter)
                 }
             }
         }
+    }
 
-        expressionPrinter.AppendLine();
-
-        foreach (var tag in Tags)
+    private void PrintSql(ExpressionPrinter expressionPrinter, bool withTags = true)
+    {
+        if (withTags)
         {
-            expressionPrinter.Append($"-- {tag}");
+            foreach (var tag in Tags)
+            {
+                expressionPrinter.Append($"-- {tag}");
+            }
         }
 
         IDisposable? indent = null;
@@ -4682,6 +4694,26 @@ protected override void Print(ExpressionPrinter expressionPrinter)
         }
     }
 
+    private string PrintShortSql()
+    {
+        var expressionPrinter = new ExpressionPrinter();
+        PrintSql(expressionPrinter, withTags: false);
+        return expressionPrinter.ToString();
+    }
+
+    /// <summary>
+    ///     <para>
+    ///         Expand this property in the debugger for a human-readable representation of this <see cref="SelectExpression" />.
+    ///     </para>
+    ///     <para>
+    ///         Warning: Do not rely on the format of the debug strings.
+    ///         They are designed for debugging only and may change arbitrarily between releases.
+    ///     </para>
+    /// </summary>
+    [EntityFrameworkInternal]
+    public DebugView DebugView
+        => new(PrintShortSql, () => this.Print());
+
     /// <inheritdoc />
     public override bool Equals(object? obj)
         => obj != null

src/EFCore.Relational/Query/SqlExpressions/SqlExpression.cs

@@ -13,7 +13,7 @@ namespace Microsoft.EntityFrameworkCore.Query.SqlExpressions;
 ///     </para>
 /// </summary>
 #if DEBUG
-[DebuggerDisplay("{new Microsoft.EntityFrameworkCore.Query.ExpressionPrinter().PrintExpression(this), nq}")]
+[DebuggerDisplay("{Microsoft.EntityFrameworkCore.Query.ExpressionPrinter.Print(this), nq}")]
 #endif
 public abstract class SqlExpression : Expression, IPrintableExpression
 {

src/EFCore.Relational/Query/SqlExpressions/TableExpressionBase.cs

@@ -12,6 +12,9 @@ namespace Microsoft.EntityFrameworkCore.Query.SqlExpressions;
 ///         not used in application code.
 ///     </para>
 /// </summary>
+#if DEBUG
+[DebuggerDisplay("{Microsoft.EntityFrameworkCore.Query.ExpressionPrinter.Print(this), nq}")]
+#endif
 public abstract class TableExpressionBase : Expression, IPrintableExpression
 {
     private readonly IReadOnlyDictionary<string, IAnnotation>? _annotations;

src/EFCore/Query/ExpressionPrinter.cs

@@ -166,16 +166,22 @@ private string PrintCore(Expression expression, int? characterLimit = null, bool
 
         Visit(expression);
 
-        var queryPlan = PostProcess(_stringBuilder.ToString());
+        return ToString();
+    }
+
+    /// <inheritdoc />
+    public override string ToString()
+    {
+        var printed = PostProcess(_stringBuilder.ToString());
 
-        if (characterLimit is > 0)
+        if (CharacterLimit is > 0)
         {
-            queryPlan = queryPlan.Length > characterLimit
-                ? queryPlan[..characterLimit.Value] + "..."
-                : queryPlan;
+            printed = printed.Length > CharacterLimit
+                ? printed[..CharacterLimit.Value] + "..."
+                : printed;
         }
 
-        return queryPlan;
+        return printed;
     }
 
     /// <summary>