diff --git a/src/PGResult.m b/src/PGResult.m
index ee2a045..fec5f65 100644
--- a/src/PGResult.m
+++ b/src/PGResult.m
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2013, 2014, 2015, 2016, 2017
+ * Copyright (c) 2012, 2013, 2014, 2015, 2016, 2017, 2024
  *   Jonathan Schleifer <js@nil.im>
  *
  * https://fossil.nil.im/objpgsql
@@ -58,7 +58,7 @@
 
 - (id)objectAtIndex: (size_t)index
 {
-	if (index > PQntuples(_result))
+	if (index > LONG_MAX || (long)index > PQntuples(_result))
 		@throw [OFOutOfRangeException exception];
 
 	return [PGResultRow pg_rowWithResult: self row: (int)index];
diff --git a/src/PGResultRow.m b/src/PGResultRow.m
index fe57b54..3c367d9 100644
--- a/src/PGResultRow.m
+++ b/src/PGResultRow.m
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019
+ * Copyright (c) 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2024
  *   Jonathan Schleifer <js@nil.im>
  *
  * https://fossil.nil.im/objpgsql
@@ -58,7 +58,7 @@ convertType(PGresult *res, int column, OFString *string)
 	int _row, _pos, _count;
 }
 
-- initWithResult: (PGResult*)result row: (int)row;
+- (instancetype)initWithResult: (PGResult*)result row: (int)row;
 @end
 
 @interface PGResultRowKeyEnumerator: PGResultRowEnumerator
@@ -143,7 +143,7 @@ convertType(PGresult *res, int column, OFString *string)
 		state->extra[1] = PQnfields(_res);
 	}
 
-	if (count > SIZE_MAX - state->state)
+	if (count < 0 || (unsigned long)count > SIZE_MAX - state->state)
 		@throw [OFOutOfRangeException exception];
 
 	if (state->state + count > state->extra[1])
diff --git a/src/exceptions/PGException.m b/src/exceptions/PGException.m
index f76574d..996bc38 100644
--- a/src/exceptions/PGException.m
+++ b/src/exceptions/PGException.m
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2013, 2014, 2015, 2016, 2017
+ * Copyright (c) 2012, 2013, 2014, 2015, 2016, 2017, 2024
  *   Jonathan Schleifer <js@nil.im>
  *
  * https://fossil.nil.im/objpgsql
@@ -32,7 +32,7 @@
 	return [[[self alloc] initWithConnection: connection] autorelease];
 }
 
-- initWithConnection: (PGConnection *)connection
+- (instancetype)initWithConnection: (PGConnection *)connection
 {
 	self = [super init];
 
diff --git a/tests/Tests.m b/tests/Tests.m
index 07c4d40..28a77c7 100644
--- a/tests/Tests.m
+++ b/tests/Tests.m
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2013, 2014, 2015, 2016, 2017, 2018
+ * Copyright (c) 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2024
  *   Jonathan Schleifer <js@nil.im>
  *
  * https://fossil.nil.im/objpgsql