Fix Ensure not using model definition alias

Author: mythz

src/ServiceStack.OrmLite/Expressions/SqlExpression.cs

@@ -615,6 +615,8 @@ protected SqlExpression<T> AppendToEnsure(Expression predicate)
             if (predicate == null)
                 return this;
 
+            Reset();
+
             var newExpr = WhereExpressionToString(Visit(predicate));
             return Ensure(newExpr);
         }

tests/ServiceStack.OrmLite.Tests/EnsureTests.cs

@@ -196,5 +196,22 @@ void assertEnsure(SqlExpression<Rockstar> q)
 
             assertEnsure(q);
         }
+        
+        [Test]
+        public void Ensure_does_use_aliases()
+        {
+            using var db = OpenDbConnection();
+            db.DropAndCreateTable<ModelWithAlias>();
+
+            db.Insert(new ModelWithAlias {
+                IntField = 1,
+            });
+
+            var q = db.From<ModelWithAlias>()
+                .Ensure(x => x.IntField > 0);
+
+            var results = db.Select(q);
+            Assert.That(results.Count, Is.EqualTo(1));
+        }
     }
 }

tests/ServiceStack.OrmLite.Tests/RowVersionTests.cs

@@ -50,6 +50,17 @@ public class ModelWithAliasedRowVersion
         public long Version { get; set; }
     }
 
+    [Alias("ModelAlias")]
+    public class ModelWithAlias
+    {
+        [Alias("ModelId")]
+        [AutoIncrement]
+        public int Id { get; set; }
+        
+        [Alias("IntAlias")]
+        public int IntField { get; set; }
+    }
+
     [Schema("Schema")]
     public class ModelWithSchemaAndRowVersionForInnerJoin
     {