Fall out from #36502

src/EFCore.Relational/Query/Internal/RelationalProjectionBindingExpressionVisitor.cs

@@ -371,8 +371,13 @@ protected override Expression VisitExtension(Expression extensionExpression)
 
                 _projectionMapping[_projectionMembers.Peek()] = projection;
 
-                return shaper.Update(
-                    new ProjectionBindingExpression(_selectExpression, _projectionMembers.Peek(), typeof(ValueBuffer)));
+                return shaper
+                    .Update(new ProjectionBindingExpression(_selectExpression, _projectionMembers.Peek(), typeof(ValueBuffer)))
+#pragma warning disable EF1001
+                    // This is to handle have correct type for the shaper expression. It is later fixed in MatchTypes.
+                    // This mirrors for structural types what we do for scalars.
+                    .MakeClrTypeNullable();
+#pragma warning restore EF1001
             }
 
             case IncludeExpression includeExpression:
@@ -658,7 +663,14 @@ private static Expression MatchTypes(Expression expression, Type targetType)
                 targetType.MakeNullable() == expression.Type,
                 $"expression has type {expression.Type.Name}, but must be nullable over {targetType.Name}");
 
-            expression = Expression.Convert(expression, targetType);
+            return expression switch
+            {
+#pragma warning disable EF1001
+                RelationalStructuralTypeShaperExpression structuralShaper => structuralShaper.MakeClrTypeNonNullable(),
+#pragma warning restore EF1001
+
+                _ =>  Expression.Convert(expression, targetType),
+            };
         }
 
         return expression;

src/EFCore.Relational/Query/RelationalSqlTranslatingExpressionVisitor.StructuralEquality.cs

@@ -333,12 +333,12 @@ bool TryRewriteComplexTypeEquality(bool collection, [NotNullWhen(true)] out SqlE
             // into complex properties to generate a flattened list of comparisons.
             // The moment we reach a a complex property that's mapped to JSON, we stop and generate a single comparison
             // for the whole complex type.
-            bool TryGenerateComparisons(
-                IComplexType type,
-                Expression left,
-                Expression right,
-                [NotNullWhen(true)] ref SqlExpression? comparisons)
+            bool TryGenerateComparisons(IComplexType complexType, Expression left, Expression right, [NotNullWhen(true)] ref SqlExpression? comparisons)
+                => TryGenerateComparisonsRec(complexType, left, right, ref comparisons, out _);
+            bool TryGenerateComparisonsRec(IComplexType type, Expression left, Expression right, [NotNullWhen(true)] ref SqlExpression? comparisons, out bool exitImmediately)
             {
+                exitImmediately = false;
+
                 if (type.IsMappedToJson())
                 {
                     var leftScalar = Process(left);
@@ -418,6 +418,17 @@ SqlParameterExpression parameter
                     {
                         var comparison = _sqlExpressionFactory.MakeBinary(nodeType, leftTranslation, rightTranslation, boolTypeMapping)!;
 
+                        // If we have a required property and one of the sides is a constant null,
+                        // we can use just that property and skip comparing the rest of properties.
+                        if (!property.IsNullable
+                            && (leftTranslation is SqlConstantExpression { Value: null }
+                                || rightTranslation is SqlConstantExpression { Value: null }))
+                        {
+                            comparisons = comparison;
+                            exitImmediately = true;
+                            return true;
+                        }
+
                         comparisons = comparisons is null
                             ? comparison
                             : nodeType == ExpressionType.Equal
@@ -447,10 +458,15 @@ SqlParameterExpression parameter
 
                     if (nestedLeft is null
                         || nestedRight is null
-                        || !TryGenerateComparisons(complexProperty.ComplexType, nestedLeft, nestedRight, ref comparisons))
+                        || !TryGenerateComparisonsRec(complexProperty.ComplexType, nestedLeft, nestedRight, ref comparisons, out exitImmediately))
                     {
                         return false;
                     }
+
+                    if (exitImmediately)
+                    {
+                        return true;
+                    }
                 }
 
                 return comparisons is not null;

src/EFCore.Relational/Query/RelationalStructuralTypeShaperExpression.cs

@@ -24,7 +24,7 @@ public class RelationalStructuralTypeShaperExpression : StructuralTypeShaperExpr
     /// <param name="valueBufferExpression">An expression of ValueBuffer to get values for properties of the entity.</param>
     /// <param name="nullable">A bool value indicating whether this entity instance can be null.</param>
     public RelationalStructuralTypeShaperExpression(ITypeBase structuralType, Expression valueBufferExpression, bool nullable)
-        : base(structuralType, valueBufferExpression, nullable, materializationCondition: null)
+        : base(structuralType, valueBufferExpression, nullable)
     {
     }
 
@@ -38,12 +38,14 @@ public RelationalStructuralTypeShaperExpression(ITypeBase structuralType, Expres
     ///     An expression of <see cref="Func{T,TResult}" /> to determine which entity type to
     ///     materialize.
     /// </param>
+    /// <param name="clrType">CLR type for this expression as returned from <see cref="Type"/>.</param>
     protected RelationalStructuralTypeShaperExpression(
         ITypeBase type,
         Expression valueBufferExpression,
         bool nullable,
-        LambdaExpression? materializationCondition)
-        : base(type, valueBufferExpression, nullable, materializationCondition)
+        LambdaExpression? materializationCondition,
+        Type clrType)
+        : base(type, valueBufferExpression, nullable, materializationCondition, clrType)
     {
     }
 
@@ -149,7 +151,7 @@ protected override LambdaExpression GenerateMaterializationCondition(ITypeBase t
     /// <inheritdoc />
     public override StructuralTypeShaperExpression WithType(ITypeBase type)
         => type != StructuralType
-            ? new RelationalStructuralTypeShaperExpression(type, ValueBufferExpression, IsNullable)
+            ? new RelationalStructuralTypeShaperExpression(type, ValueBufferExpression, IsNullable, materializationCondition: null, type.ClrType)
             : this;
 
     /// <inheritdoc />
@@ -175,12 +177,24 @@ public override StructuralTypeShaperExpression MakeNullable(bool nullable = true
         }
 
         // Marking nullable requires re-computation of Discriminator condition
-        return new RelationalStructuralTypeShaperExpression(StructuralType, newValueBufferExpression, true);
+        return new RelationalStructuralTypeShaperExpression(StructuralType, newValueBufferExpression, true, materializationCondition: null, Type);
     }
 
     /// <inheritdoc />
     public override StructuralTypeShaperExpression Update(Expression valueBufferExpression)
         => valueBufferExpression != ValueBufferExpression
-            ? new RelationalStructuralTypeShaperExpression(StructuralType, valueBufferExpression, IsNullable, MaterializationCondition)
+            ? new RelationalStructuralTypeShaperExpression(StructuralType, valueBufferExpression, IsNullable, MaterializationCondition, Type)
+            : this;
+
+    /// <inheritdoc />
+    public override StructuralTypeShaperExpression MakeClrTypeNullable()
+        => Type != Type.MakeNullable()
+            ? new RelationalStructuralTypeShaperExpression(StructuralType, ValueBufferExpression, IsNullable, MaterializationCondition, Type.MakeNullable())
+            : this;
+
+    /// <inheritdoc />
+    public override StructuralTypeShaperExpression MakeClrTypeNonNullable()
+        => Type != Type.UnwrapNullableType()
+            ? new RelationalStructuralTypeShaperExpression(StructuralType, ValueBufferExpression, IsNullable, MaterializationCondition, Type.UnwrapNullableType())
             : this;
 }

src/EFCore/Query/EntityMaterializerSourceParameters.cs

@@ -8,14 +8,14 @@ namespace Microsoft.EntityFrameworkCore.Query;
 /// </summary>
 /// <param name="StructuralType">The entity or complex type being materialized.</param>
 /// <param name="InstanceName">The name of the instance being materialized.</param>
-/// <param name="AllowNullable">Whether nullable result is allowed.</param>
+/// <param name="ClrType">CLR type of the result.</param>
 /// <param name="QueryTrackingBehavior">
 ///     The query tracking behavior, or <see langword="null" /> if this materialization is not from a query.
 /// </param>
 public readonly record struct StructuralTypeMaterializerSourceParameters(
     ITypeBase StructuralType,
     string InstanceName,
-    bool? AllowNullable,
+    Type ClrType,
     QueryTrackingBehavior? QueryTrackingBehavior);
 
 /// <summary>