diff --git a/test/yulPhaser/Mutations.cpp b/test/yulPhaser/Mutations.cpp
index 86e9992f9..b20cb8e4c 100644
--- a/test/yulPhaser/Mutations.cpp
+++ b/test/yulPhaser/Mutations.cpp
@@ -179,8 +179,8 @@ BOOST_AUTO_TEST_CASE(alternativeMutations_should_choose_between_mutations_with_g
 	for (size_t i = 0; i < 10; ++i)
 	{
 		Chromosome mutatedChromosome = mutation(chromosome);
-		cCount += static_cast<int>(mutatedChromosome == Chromosome("c"));
-		fCount += static_cast<int>(mutatedChromosome == Chromosome("f"));
+		cCount += (mutatedChromosome == Chromosome("c") ? 1 : 0);
+		fCount += (mutatedChromosome == Chromosome("f") ? 1 : 0);
 	}
 
 	// This particular seed results in 7 "c"s out of 10 which looks plausible given the 80% chance.
diff --git a/test/yulPhaser/Population.cpp b/test/yulPhaser/Population.cpp
index 1657e97c9..5fd8c2073 100644
--- a/test/yulPhaser/Population.cpp
+++ b/test/yulPhaser/Population.cpp
@@ -135,7 +135,7 @@ BOOST_FIXTURE_TEST_CASE(makeRandom_should_get_chromosome_lengths_from_specified_
 	size_t maxLength = 5;
 	assert(chromosomeCount % maxLength == 0);
 
-	auto nextLength = [counter = 0, maxLength]() mutable { return counter++ % maxLength; };
+	auto nextLength = [counter = 0ul, maxLength]() mutable { return counter++ % maxLength; };
 	auto population = Population::makeRandom(m_fitnessMetric, chromosomeCount, nextLength);
 
 	// We can't rely on the order since the population sorts its chromosomes immediately but
diff --git a/test/yulPhaser/TestHelpers.cpp b/test/yulPhaser/TestHelpers.cpp
index 2379016fe..2f4b40b02 100644
--- a/test/yulPhaser/TestHelpers.cpp
+++ b/test/yulPhaser/TestHelpers.cpp
@@ -72,9 +72,13 @@ size_t phaser::test::countDifferences(Chromosome const& _chromosome1, Chromosome
 {
 	size_t count = 0;
 	for (size_t i = 0; i < min(_chromosome1.length(), _chromosome2.length()); ++i)
-		count += static_cast<int>(_chromosome1.optimisationSteps()[i] != _chromosome2.optimisationSteps()[i]);
+		if (_chromosome1.optimisationSteps()[i] != _chromosome2.optimisationSteps()[i])
+			++count;
 
-	return count + abs(static_cast<int>(_chromosome1.length() - _chromosome2.length()));
+	return count + static_cast<size_t>(abs(
+		static_cast<long>(_chromosome1.length()) -
+		static_cast<long>(_chromosome2.length())
+	));
 }
 
 TemporaryDirectory::TemporaryDirectory(std::string const& _prefix):