diff --git a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/ColumnType.kt b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/ColumnType.kt
index 2e96cb7385..dcc71027c4 100644
--- a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/ColumnType.kt
+++ b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/ColumnType.kt
@@ -63,7 +63,7 @@ interface IColumnType {
 
     /** Sets the [value] at the specified [index] into the [stmt]. */
     fun setParameter(stmt: PreparedStatementApi, index: Int, value: Any?) {
-        if (value == null || value == Op.NULL) {
+        if (value == null || value is Op.NULL) {
             stmt.setNull(index, this)
         } else {
             stmt[index] = value
@@ -722,7 +722,7 @@ class BlobColumnType : ColumnType() {
     override fun setParameter(stmt: PreparedStatementApi, index: Int, value: Any?) {
         when (val toSetValue = (value as? ExposedBlob)?.bytes?.inputStream() ?: value) {
             is InputStream -> stmt.setInputStream(index, toSetValue)
-            null, Op.NULL -> stmt.setNull(index, this)
+            null, is Op.NULL -> stmt.setNull(index, this)
             else -> super.setParameter(stmt, index, toSetValue)
         }
     }
diff --git a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Op.kt b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Op.kt
index e6ce637ed5..1fa7a39415 100644
--- a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Op.kt
+++ b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Op.kt
@@ -12,7 +12,7 @@ abstract class Op<T> : Expression<T>() {
         /** Builds a new operator using provided [op]. */
         inline fun <T> build(op: SqlExpressionBuilder.() -> Op<T>): Op<T> = SqlExpressionBuilder.op()
 
-        fun <T> nullOp() : Op<T> = NULL as Op<T>
+        fun <T> nullOp(): Op<T> = NULL as Op<T>
     }
 
     internal interface OpBoolean
diff --git a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/SQLExpressionBuilder.kt b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/SQLExpressionBuilder.kt
index dbc93be5c0..eb84d714bc 100644
--- a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/SQLExpressionBuilder.kt
+++ b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/SQLExpressionBuilder.kt
@@ -168,8 +168,8 @@ interface ISqlExpressionBuilder {
     infix fun <T> ExpressionWithColumnType<T>.neq(other: T): Op<Boolean> = if (other == null) isNotNull() else NeqOp(this, wrap(other))
 
     /** Checks if this expression is not equals to some [other] expression. */
-    infix fun <T, S1 : T?, S2 : T?> Expression<in S1>.neq(other: Expression<in S2>): Op<Boolean> = when {
-        other.equals(Op.NULL) -> isNotNull()
+    infix fun <T, S1 : T?, S2 : T?> Expression<in S1>.neq(other: Expression<in S2>): Op<Boolean> = when (other as Expression<*>) {
+        is Op.NULL -> isNotNull()
         else -> NeqOp(this, other)
     }
 
diff --git a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/statements/UpdateBuilder.kt b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/statements/UpdateBuilder.kt
index 00cfd3a9cb..d9c9e74562 100644
--- a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/statements/UpdateBuilder.kt
+++ b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/statements/UpdateBuilder.kt
@@ -27,7 +27,7 @@ abstract class UpdateBuilder<out T>(type: StatementType, targets: List<Table>) :
     }
 
     open operator fun <S> set(column: Column<S>, value: S) {
-        require(column.columnType.nullable || (value != null && value != Op.NULL)) {
+        require(column.columnType.nullable || (value != null && value !is Op.NULL)) {
             "Trying to set null to not nullable column $column"
         }
 
@@ -43,7 +43,7 @@ abstract class UpdateBuilder<out T>(type: StatementType, targets: List<Table>) :
 
     @JvmName("setWithEntityIdExpression")
     operator fun <S : Any?, ID : EntityID<S>, E : Expression<S>> set(column: Column<ID>, value: E) {
-        require(column.columnType.nullable || value != Op.NULL) {
+        require(column.columnType.nullable || value !is Op.NULL) {
             "Trying to set null to not nullable column $column"
         }
         checkThatExpressionWasNotSetInPreviousBatch(column)