diff --git a/lib/private/DB/QueryBuilder/ExpressionBuilder/ExpressionBuilder.php b/lib/private/DB/QueryBuilder/ExpressionBuilder/ExpressionBuilder.php
index d4c1a9db88..ebc7f9fb77 100644
--- a/lib/private/DB/QueryBuilder/ExpressionBuilder/ExpressionBuilder.php
+++ b/lib/private/DB/QueryBuilder/ExpressionBuilder/ExpressionBuilder.php
@@ -33,6 +33,7 @@ use OC\DB\QueryBuilder\FunctionBuilder\FunctionBuilder;
 use OC\DB\QueryBuilder\Literal;
 use OC\DB\QueryBuilder\QueryFunction;
 use OC\DB\QueryBuilder\QuoteHelper;
+use OCP\DB\QueryBuilder\ICompositeExpression;
 use OCP\DB\QueryBuilder\IExpressionBuilder;
 use OCP\DB\QueryBuilder\ILiteral;
 use OCP\DB\QueryBuilder\IParameter;
@@ -80,7 +81,7 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 *
 	 * @return \OCP\DB\QueryBuilder\ICompositeExpression
 	 */
-	public function andX(...$x) {
+	public function andX(...$x): ICompositeExpression {
 		$compositeExpression = call_user_func_array([$this->expressionBuilder, 'andX'], $x);
 		return new CompositeExpression($compositeExpression);
 	}
@@ -99,7 +100,7 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 *
 	 * @return \OCP\DB\QueryBuilder\ICompositeExpression
 	 */
-	public function orX(...$x) {
+	public function orX(...$x): ICompositeExpression {
 		$compositeExpression = call_user_func_array([$this->expressionBuilder, 'orX'], $x);
 		return new CompositeExpression($compositeExpression);
 	}
@@ -115,7 +116,7 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 *
 	 * @return string
 	 */
-	public function comparison($x, $operator, $y, $type = null) {
+	public function comparison($x, string $operator, $y, $type = null): string {
 		$x = $this->helper->quoteColumnName($x);
 		$y = $this->helper->quoteColumnName($y);
 		return $this->expressionBuilder->comparison($x, $operator, $y);
@@ -138,7 +139,7 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 *
 	 * @return string
 	 */
-	public function eq($x, $y, $type = null) {
+	public function eq($x, $y, $type = null): string {
 		$x = $this->helper->quoteColumnName($x);
 		$y = $this->helper->quoteColumnName($y);
 		return $this->expressionBuilder->eq($x, $y);
@@ -160,7 +161,7 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 *
 	 * @return string
 	 */
-	public function neq($x, $y, $type = null) {
+	public function neq($x, $y, $type = null): string {
 		$x = $this->helper->quoteColumnName($x);
 		$y = $this->helper->quoteColumnName($y);
 		return $this->expressionBuilder->neq($x, $y);
@@ -182,7 +183,7 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 *
 	 * @return string
 	 */
-	public function lt($x, $y, $type = null) {
+	public function lt($x, $y, $type = null): string {
 		$x = $this->helper->quoteColumnName($x);
 		$y = $this->helper->quoteColumnName($y);
 		return $this->expressionBuilder->lt($x, $y);
@@ -204,7 +205,7 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 *
 	 * @return string
 	 */
-	public function lte($x, $y, $type = null) {
+	public function lte($x, $y, $type = null): string {
 		$x = $this->helper->quoteColumnName($x);
 		$y = $this->helper->quoteColumnName($y);
 		return $this->expressionBuilder->lte($x, $y);
@@ -226,7 +227,7 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 *
 	 * @return string
 	 */
-	public function gt($x, $y, $type = null) {
+	public function gt($x, $y, $type = null): string {
 		$x = $this->helper->quoteColumnName($x);
 		$y = $this->helper->quoteColumnName($y);
 		return $this->expressionBuilder->gt($x, $y);
@@ -248,7 +249,7 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 *
 	 * @return string
 	 */
-	public function gte($x, $y, $type = null) {
+	public function gte($x, $y, $type = null): string {
 		$x = $this->helper->quoteColumnName($x);
 		$y = $this->helper->quoteColumnName($y);
 		return $this->expressionBuilder->gte($x, $y);
@@ -257,11 +258,11 @@ class ExpressionBuilder implements IExpressionBuilder {
 	/**
 	 * Creates an IS NULL expression with the given arguments.
 	 *
-	 * @param string $x The field in string format to be restricted by IS NULL.
+	 * @param string|ILiteral|IParameter|IQueryFunction $x The field in string format to be restricted by IS NULL.
 	 *
 	 * @return string
 	 */
-	public function isNull($x) {
+	public function isNull($x): string {
 		$x = $this->helper->quoteColumnName($x);
 		return $this->expressionBuilder->isNull($x);
 	}
@@ -269,11 +270,11 @@ class ExpressionBuilder implements IExpressionBuilder {
 	/**
 	 * Creates an IS NOT NULL expression with the given arguments.
 	 *
-	 * @param string $x The field in string format to be restricted by IS NOT NULL.
+	 * @param string|ILiteral|IParameter|IQueryFunction $x The field in string format to be restricted by IS NOT NULL.
 	 *
 	 * @return string
 	 */
-	public function isNotNull($x) {
+	public function isNotNull($x): string {
 		$x = $this->helper->quoteColumnName($x);
 		return $this->expressionBuilder->isNotNull($x);
 	}
@@ -288,7 +289,7 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 *
 	 * @return string
 	 */
-	public function like($x, $y, $type = null) {
+	public function like($x, $y, $type = null): string {
 		$x = $this->helper->quoteColumnName($x);
 		$y = $this->helper->quoteColumnName($y);
 		return $this->expressionBuilder->like($x, $y);
@@ -305,7 +306,7 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 * @return string
 	 * @since 9.0.0
 	 */
-	public function iLike($x, $y, $type = null) {
+	public function iLike($x, $y, $type = null): string {
 		return $this->expressionBuilder->like($this->functionBuilder->lower($x), $this->functionBuilder->lower($y));
 	}
 
@@ -319,7 +320,7 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 *
 	 * @return string
 	 */
-	public function notLike($x, $y, $type = null) {
+	public function notLike($x, $y, $type = null): string {
 		$x = $this->helper->quoteColumnName($x);
 		$y = $this->helper->quoteColumnName($y);
 		return $this->expressionBuilder->notLike($x, $y);
@@ -335,7 +336,7 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 *
 	 * @return string
 	 */
-	public function in($x, $y, $type = null) {
+	public function in($x, $y, $type = null): string {
 		$x = $this->helper->quoteColumnName($x);
 		$y = $this->helper->quoteColumnNames($y);
 		return $this->expressionBuilder->in($x, $y);
@@ -351,7 +352,7 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 *
 	 * @return string
 	 */
-	public function notIn($x, $y, $type = null) {
+	public function notIn($x, $y, $type = null): string {
 		$x = $this->helper->quoteColumnName($x);
 		$y = $this->helper->quoteColumnNames($y);
 		return $this->expressionBuilder->notIn($x, $y);
@@ -360,22 +361,22 @@ class ExpressionBuilder implements IExpressionBuilder {
 	/**
 	 * Creates a $x = '' statement, because Oracle needs a different check
 	 *
-	 * @param string $x The field in string format to be inspected by the comparison.
+	 * @param string|ILiteral|IParameter|IQueryFunction $x The field in string format to be inspected by the comparison.
 	 * @return string
 	 * @since 13.0.0
 	 */
-	public function emptyString($x) {
+	public function emptyString($x): string {
 		return $this->eq($x, $this->literal('', IQueryBuilder::PARAM_STR));
 	}
 
 	/**
 	 * Creates a `$x <> ''` statement, because Oracle needs a different check
 	 *
-	 * @param string $x The field in string format to be inspected by the comparison.
+	 * @param string|ILiteral|IParameter|IQueryFunction $x The field in string format to be inspected by the comparison.
 	 * @return string
 	 * @since 13.0.0
 	 */
-	public function nonEmptyString($x) {
+	public function nonEmptyString($x): string {
 		return $this->neq($x, $this->literal('', IQueryBuilder::PARAM_STR));
 	}
 
@@ -387,7 +388,7 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 * @return IQueryFunction
 	 * @since 12.0.0
 	 */
-	public function bitwiseAnd($x, $y) {
+	public function bitwiseAnd($x, int $y): IQueryFunction {
 		return new QueryFunction($this->connection->getDatabasePlatform()->getBitAndComparisonExpression(
 			$this->helper->quoteColumnName($x),
 			$y
@@ -402,7 +403,7 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 * @return IQueryFunction
 	 * @since 12.0.0
 	 */
-	public function bitwiseOr($x, $y) {
+	public function bitwiseOr($x, int $y): IQueryFunction {
 		return new QueryFunction($this->connection->getDatabasePlatform()->getBitOrComparisonExpression(
 			$this->helper->quoteColumnName($x),
 			$y
@@ -417,7 +418,7 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 *
 	 * @return ILiteral
 	 */
-	public function literal($input, $type = null) {
+	public function literal($input, $type = null): ILiteral {
 		return new Literal($this->expressionBuilder->literal($input, $type));
 	}
 
@@ -426,9 +427,9 @@ class ExpressionBuilder implements IExpressionBuilder {
 	 *
 	 * @param string $column
 	 * @param mixed $type One of IQueryBuilder::PARAM_*
-	 * @return string
+	 * @return IQueryFunction
 	 */
-	public function castColumn($column, $type) {
+	public function castColumn(string $column, $type): IQueryFunction {
 		return new QueryFunction(
 			$this->helper->quoteColumnName($column)
 		);
diff --git a/lib/private/DB/QueryBuilder/ExpressionBuilder/MySqlExpressionBuilder.php b/lib/private/DB/QueryBuilder/ExpressionBuilder/MySqlExpressionBuilder.php
index 3e4119bb11..86f7cf4350 100644
--- a/lib/private/DB/QueryBuilder/ExpressionBuilder/MySqlExpressionBuilder.php
+++ b/lib/private/DB/QueryBuilder/ExpressionBuilder/MySqlExpressionBuilder.php
@@ -46,7 +46,7 @@ class MySqlExpressionBuilder extends ExpressionBuilder {
 	/**
 	 * @inheritdoc
 	 */
-	public function iLike($x, $y, $type = null) {
+	public function iLike($x, $y, $type = null): string {
 		$x = $this->helper->quoteColumnName($x);
 		$y = $this->helper->quoteColumnName($y);
 		return $this->expressionBuilder->comparison($x, ' COLLATE ' . $this->charset . '_general_ci LIKE', $y);
diff --git a/lib/private/DB/QueryBuilder/ExpressionBuilder/OCIExpressionBuilder.php b/lib/private/DB/QueryBuilder/ExpressionBuilder/OCIExpressionBuilder.php
index f41242fdc6..86212c577a 100644
--- a/lib/private/DB/QueryBuilder/ExpressionBuilder/OCIExpressionBuilder.php
+++ b/lib/private/DB/QueryBuilder/ExpressionBuilder/OCIExpressionBuilder.php
@@ -49,7 +49,7 @@ class OCIExpressionBuilder extends ExpressionBuilder {
 	/**
 	 * @inheritdoc
 	 */
-	public function comparison($x, $operator, $y, $type = null) {
+	public function comparison($x, string $operator, $y, $type = null): string {
 		$x = $this->prepareColumn($x, $type);
 		$y = $this->prepareColumn($y, $type);
 
@@ -59,7 +59,7 @@ class OCIExpressionBuilder extends ExpressionBuilder {
 	/**
 	 * @inheritdoc
 	 */
-	public function eq($x, $y, $type = null) {
+	public function eq($x, $y, $type = null): string {
 		$x = $this->prepareColumn($x, $type);
 		$y = $this->prepareColumn($y, $type);
 
@@ -69,7 +69,7 @@ class OCIExpressionBuilder extends ExpressionBuilder {
 	/**
 	 * @inheritdoc
 	 */
-	public function neq($x, $y, $type = null) {
+	public function neq($x, $y, $type = null): string {
 		$x = $this->prepareColumn($x, $type);
 		$y = $this->prepareColumn($y, $type);
 
@@ -79,7 +79,7 @@ class OCIExpressionBuilder extends ExpressionBuilder {
 	/**
 	 * @inheritdoc
 	 */
-	public function lt($x, $y, $type = null) {
+	public function lt($x, $y, $type = null): string {
 		$x = $this->prepareColumn($x, $type);
 		$y = $this->prepareColumn($y, $type);
 
@@ -89,7 +89,7 @@ class OCIExpressionBuilder extends ExpressionBuilder {
 	/**
 	 * @inheritdoc
 	 */
-	public function lte($x, $y, $type = null) {
+	public function lte($x, $y, $type = null): string {
 		$x = $this->prepareColumn($x, $type);
 		$y = $this->prepareColumn($y, $type);
 
@@ -99,7 +99,7 @@ class OCIExpressionBuilder extends ExpressionBuilder {
 	/**
 	 * @inheritdoc
 	 */
-	public function gt($x, $y, $type = null) {
+	public function gt($x, $y, $type = null): string {
 		$x = $this->prepareColumn($x, $type);
 		$y = $this->prepareColumn($y, $type);
 
@@ -109,7 +109,7 @@ class OCIExpressionBuilder extends ExpressionBuilder {
 	/**
 	 * @inheritdoc
 	 */
-	public function gte($x, $y, $type = null) {
+	public function gte($x, $y, $type = null): string {
 		$x = $this->prepareColumn($x, $type);
 		$y = $this->prepareColumn($y, $type);
 
@@ -119,7 +119,7 @@ class OCIExpressionBuilder extends ExpressionBuilder {
 	/**
 	 * @inheritdoc
 	 */
-	public function in($x, $y, $type = null) {
+	public function in($x, $y, $type = null): string {
 		$x = $this->prepareColumn($x, $type);
 		$y = $this->prepareColumn($y, $type);
 
@@ -129,7 +129,7 @@ class OCIExpressionBuilder extends ExpressionBuilder {
 	/**
 	 * @inheritdoc
 	 */
-	public function notIn($x, $y, $type = null) {
+	public function notIn($x, $y, $type = null): string {
 		$x = $this->prepareColumn($x, $type);
 		$y = $this->prepareColumn($y, $type);
 
@@ -139,22 +139,22 @@ class OCIExpressionBuilder extends ExpressionBuilder {
 	/**
 	 * Creates a $x = '' statement, because Oracle needs a different check
 	 *
-	 * @param string $x The field in string format to be inspected by the comparison.
+	 * @param string|ILiteral|IParameter|IQueryFunction $x The field in string format to be inspected by the comparison.
 	 * @return string
 	 * @since 13.0.0
 	 */
-	public function emptyString($x) {
+	public function emptyString($x): string {
 		return $this->isNull($x);
 	}
 
 	/**
 	 * Creates a `$x <> ''` statement, because Oracle needs a different check
 	 *
-	 * @param string $x The field in string format to be inspected by the comparison.
+	 * @param string|ILiteral|IParameter|IQueryFunction $x The field in string format to be inspected by the comparison.
 	 * @return string
 	 * @since 13.0.0
 	 */
-	public function nonEmptyString($x) {
+	public function nonEmptyString($x): string {
 		return $this->isNotNull($x);
 	}
 
@@ -165,7 +165,7 @@ class OCIExpressionBuilder extends ExpressionBuilder {
 	 * @param mixed $type One of IQueryBuilder::PARAM_*
 	 * @return IQueryFunction
 	 */
-	public function castColumn($column, $type) {
+	public function castColumn(string $column, $type): IQueryFunction {
 		if ($type === IQueryBuilder::PARAM_STR) {
 			$column = $this->helper->quoteColumnName($column);
 			return new QueryFunction('to_char(' . $column . ')');
@@ -181,14 +181,14 @@ class OCIExpressionBuilder extends ExpressionBuilder {
 	/**
 	 * @inheritdoc
 	 */
-	public function like($x, $y, $type = null) {
+	public function like($x, $y, $type = null): string {
 		return parent::like($x, $y, $type) . " ESCAPE '\\'";
 	}
 
 	/**
 	 * @inheritdoc
 	 */
-	public function iLike($x, $y, $type = null) {
+	public function iLike($x, $y, $type = null): string {
 		return $this->like($this->functionBuilder->lower($x), $this->functionBuilder->lower($y));
 	}
 }
diff --git a/lib/private/DB/QueryBuilder/ExpressionBuilder/PgSqlExpressionBuilder.php b/lib/private/DB/QueryBuilder/ExpressionBuilder/PgSqlExpressionBuilder.php
index 141a93ff75..3e8cdd698b 100644
--- a/lib/private/DB/QueryBuilder/ExpressionBuilder/PgSqlExpressionBuilder.php
+++ b/lib/private/DB/QueryBuilder/ExpressionBuilder/PgSqlExpressionBuilder.php
@@ -26,6 +26,7 @@ namespace OC\DB\QueryBuilder\ExpressionBuilder;
 
 use OC\DB\QueryBuilder\QueryFunction;
 use OCP\DB\QueryBuilder\IQueryBuilder;
+use OCP\DB\QueryBuilder\IQueryFunction;
 
 class PgSqlExpressionBuilder extends ExpressionBuilder {
 
@@ -34,9 +35,9 @@ class PgSqlExpressionBuilder extends ExpressionBuilder {
 	 *
 	 * @param string $column
 	 * @param mixed $type One of IQueryBuilder::PARAM_*
-	 * @return string
+	 * @return IQueryFunction
 	 */
-	public function castColumn($column, $type) {
+	public function castColumn($column, $type): IQueryFunction {
 		switch ($type) {
 			case IQueryBuilder::PARAM_INT:
 				return new QueryFunction('CAST(' . $this->helper->quoteColumnName($column) . ' AS INT)');
@@ -50,7 +51,7 @@ class PgSqlExpressionBuilder extends ExpressionBuilder {
 	/**
 	 * @inheritdoc
 	 */
-	public function iLike($x, $y, $type = null) {
+	public function iLike($x, $y, $type = null): string {
 		$x = $this->helper->quoteColumnName($x);
 		$y = $this->helper->quoteColumnName($y);
 		return $this->expressionBuilder->comparison($x, 'ILIKE', $y);
diff --git a/lib/private/DB/QueryBuilder/ExpressionBuilder/SqliteExpressionBuilder.php b/lib/private/DB/QueryBuilder/ExpressionBuilder/SqliteExpressionBuilder.php
index 1fa0d79663..92f1d9ed3b 100644
--- a/lib/private/DB/QueryBuilder/ExpressionBuilder/SqliteExpressionBuilder.php
+++ b/lib/private/DB/QueryBuilder/ExpressionBuilder/SqliteExpressionBuilder.php
@@ -27,11 +27,11 @@ class SqliteExpressionBuilder extends ExpressionBuilder {
 	/**
 	 * @inheritdoc
 	 */
-	public function like($x, $y, $type = null) {
+	public function like($x, $y, $type = null): string {
 		return parent::like($x, $y, $type) . " ESCAPE '\\'";
 	}
 
-	public function iLike($x, $y, $type = null) {
+	public function iLike($x, $y, $type = null): string {
 		return $this->like($this->functionBuilder->lower($x), $this->functionBuilder->lower($y), $type);
 	}
 }
diff --git a/lib/public/DB/QueryBuilder/IExpressionBuilder.php b/lib/public/DB/QueryBuilder/IExpressionBuilder.php
index aebc4bde9c..dcba559a96 100644
--- a/lib/public/DB/QueryBuilder/IExpressionBuilder.php
+++ b/lib/public/DB/QueryBuilder/IExpressionBuilder.php
@@ -78,7 +78,7 @@ interface IExpressionBuilder {
 	 *
 	 * @psalm-taint-sink sql $x
 	 */
-	public function andX(...$x);
+	public function andX(...$x): ICompositeExpression;
 
 	/**
 	 * Creates a disjunction of the given boolean expressions.
@@ -97,7 +97,7 @@ interface IExpressionBuilder {
 	 *
 	 * @psalm-taint-sink sql $x
 	 */
-	public function orX(...$x);
+	public function orX(...$x): ICompositeExpression;
 
 	/**
 	 * Creates a comparison expression.
@@ -116,7 +116,7 @@ interface IExpressionBuilder {
 	 * @psalm-taint-sink sql $y
 	 * @psalm-taint-sink sql $type
 	 */
-	public function comparison($x, $operator, $y, $type = null);
+	public function comparison($x, string $operator, $y, $type = null): string;
 
 	/**
 	 * Creates an equality comparison expression with the given arguments.
@@ -140,7 +140,7 @@ interface IExpressionBuilder {
 	 * @psalm-taint-sink sql $y
 	 * @psalm-taint-sink sql $type
 	 */
-	public function eq($x, $y, $type = null);
+	public function eq($x, $y, $type = null): string;
 
 	/**
 	 * Creates a non equality comparison expression with the given arguments.
@@ -163,7 +163,7 @@ interface IExpressionBuilder {
 	 * @psalm-taint-sink sql $y
 	 * @psalm-taint-sink sql $type
 	 */
-	public function neq($x, $y, $type = null);
+	public function neq($x, $y, $type = null): string;
 
 	/**
 	 * Creates a lower-than comparison expression with the given arguments.
@@ -186,7 +186,7 @@ interface IExpressionBuilder {
 	 * @psalm-taint-sink sql $y
 	 * @psalm-taint-sink sql $type
 	 */
-	public function lt($x, $y, $type = null);
+	public function lt($x, $y, $type = null): string;
 
 	/**
 	 * Creates a lower-than-equal comparison expression with the given arguments.
@@ -209,7 +209,7 @@ interface IExpressionBuilder {
 	 * @psalm-taint-sink sql $y
 	 * @psalm-taint-sink sql $type
 	 */
-	public function lte($x, $y, $type = null);
+	public function lte($x, $y, $type = null): string;
 
 	/**
 	 * Creates a greater-than comparison expression with the given arguments.
@@ -232,7 +232,7 @@ interface IExpressionBuilder {
 	 * @psalm-taint-sink sql $y
 	 * @psalm-taint-sink sql $type
 	 */
-	public function gt($x, $y, $type = null);
+	public function gt($x, $y, $type = null): string;
 
 	/**
 	 * Creates a greater-than-equal comparison expression with the given arguments.
@@ -255,31 +255,31 @@ interface IExpressionBuilder {
 	 * @psalm-taint-sink sql $y
 	 * @psalm-taint-sink sql $type
 	 */
-	public function gte($x, $y, $type = null);
+	public function gte($x, $y, $type = null): string;
 
 	/**
 	 * Creates an IS NULL expression with the given arguments.
 	 *
-	 * @param string $x The field in string format to be restricted by IS NULL.
+	 * @param string|ILiteral|IParameter|IQueryFunction $x The field in string format to be restricted by IS NULL.
 	 *
 	 * @return string
 	 * @since 8.2.0
 	 *
 	 * @psalm-taint-sink sql $x
 	 */
-	public function isNull($x);
+	public function isNull($x): string;
 
 	/**
 	 * Creates an IS NOT NULL expression with the given arguments.
 	 *
-	 * @param string $x The field in string format to be restricted by IS NOT NULL.
+	 * @param string|ILiteral|IParameter|IQueryFunction $x The field in string format to be restricted by IS NOT NULL.
 	 *
 	 * @return string
 	 * @since 8.2.0
 	 *
 	 * @psalm-taint-sink sql $x
 	 */
-	public function isNotNull($x);
+	public function isNotNull($x): string;
 
 	/**
 	 * Creates a LIKE() comparison expression with the given arguments.
@@ -296,7 +296,7 @@ interface IExpressionBuilder {
 	 * @psalm-taint-sink sql $y
 	 * @psalm-taint-sink sql $type
 	 */
-	public function like($x, $y, $type = null);
+	public function like($x, $y, $type = null): string;
 
 	/**
 	 * Creates a NOT LIKE() comparison expression with the given arguments.
@@ -313,7 +313,7 @@ interface IExpressionBuilder {
 	 * @psalm-taint-sink sql $y
 	 * @psalm-taint-sink sql $type
 	 */
-	public function notLike($x, $y, $type = null);
+	public function notLike($x, $y, $type = null): string;
 
 	/**
 	 * Creates a ILIKE() comparison expression with the given arguments.
@@ -330,7 +330,7 @@ interface IExpressionBuilder {
 	 * @psalm-taint-sink sql $y
 	 * @psalm-taint-sink sql $type
 	 */
-	public function iLike($x, $y, $type = null);
+	public function iLike($x, $y, $type = null): string;
 
 	/**
 	 * Creates a IN () comparison expression with the given arguments.
@@ -347,7 +347,7 @@ interface IExpressionBuilder {
 	 * @psalm-taint-sink sql $y
 	 * @psalm-taint-sink sql $type
 	 */
-	public function in($x, $y, $type = null);
+	public function in($x, $y, $type = null): string;
 
 	/**
 	 * Creates a NOT IN () comparison expression with the given arguments.
@@ -364,29 +364,29 @@ interface IExpressionBuilder {
 	 * @psalm-taint-sink sql $y
 	 * @psalm-taint-sink sql $type
 	 */
-	public function notIn($x, $y, $type = null);
+	public function notIn($x, $y, $type = null): string;
 
 	/**
 	 * Creates a $x = '' statement, because Oracle needs a different check
 	 *
-	 * @param string $x The field in string format to be inspected by the comparison.
+	 * @param string|ILiteral|IParameter|IQueryFunction $x The field in string format to be inspected by the comparison.
 	 * @return string
 	 * @since 13.0.0
 	 *
 	 * @psalm-taint-sink sql $x
 	 */
-	public function emptyString($x);
+	public function emptyString($x): string;
 
 	/**
 	 * Creates a `$x <> ''` statement, because Oracle needs a different check
 	 *
-	 * @param string $x The field in string format to be inspected by the comparison.
+	 * @param string|ILiteral|IParameter|IQueryFunction $x The field in string format to be inspected by the comparison.
 	 * @return string
 	 * @since 13.0.0
 	 *
 	 * @psalm-taint-sink sql $x
 	 */
-	public function nonEmptyString($x);
+	public function nonEmptyString($x): string;
 
 
 	/**
@@ -400,7 +400,7 @@ interface IExpressionBuilder {
 	 * @psalm-taint-sink sql $x
 	 * @psalm-taint-sink sql $y
 	 */
-	public function bitwiseAnd($x, $y);
+	public function bitwiseAnd($x, int $y): IQueryFunction;
 
 	/**
 	 * Creates a bitwise OR comparison
@@ -413,7 +413,7 @@ interface IExpressionBuilder {
 	 * @psalm-taint-sink sql $x
 	 * @psalm-taint-sink sql $y
 	 */
-	public function bitwiseOr($x, $y);
+	public function bitwiseOr($x, int $y): IQueryFunction;
 
 	/**
 	 * Quotes a given input parameter.
@@ -421,24 +421,24 @@ interface IExpressionBuilder {
 	 * @param mixed $input The parameter to be quoted.
 	 * @param mixed|null $type One of the IQueryBuilder::PARAM_* constants
 	 *
-	 * @return string
+	 * @return ILiteral
 	 * @since 8.2.0
 	 *
 	 * @psalm-taint-sink sql $input
 	 * @psalm-taint-sink sql $type
 	 */
-	public function literal($input, $type = null);
+	public function literal($input, $type = null): ILiteral;
 
 	/**
 	 * Returns a IQueryFunction that casts the column to the given type
 	 *
 	 * @param string $column
 	 * @param mixed $type One of IQueryBuilder::PARAM_*
-	 * @return string
+	 * @return IQueryFunction
 	 * @since 9.0.0
 	 *
 	 * @psalm-taint-sink sql $column
 	 * @psalm-taint-sink sql $type
 	 */
-	public function castColumn($column, $type);
+	public function castColumn(string $column, $type): IQueryFunction;
 }