diff --git a/include/util.hpp b/include/util.hpp
index 90c1235b..3d8b208a 100644
--- a/include/util.hpp
+++ b/include/util.hpp
@@ -51,7 +51,7 @@ char const *printChar(int c);
 struct Uppercase {
 	// FNV-1a hash of an uppercased string
 	constexpr size_t operator()(std::string const &str) const {
-		return std::accumulate(RANGE(str), 0x811C9DC5, [](size_t hash, char c) {
+		return std::accumulate(RANGE(str), size_t(0x811C9DC5), [](size_t hash, char c) {
 			return (hash ^ toUpper(c)) * 16777619;
 		});
 	}
diff --git a/src/diagnostics.cpp b/src/diagnostics.cpp
index af3c81dd..b610c9df 100644
--- a/src/diagnostics.cpp
+++ b/src/diagnostics.cpp
@@ -76,5 +76,5 @@ std::pair<WarningState, std::optional<uint32_t>> getInitialWarningState(std::str
 		}
 	}
 
-	return {state, param > UINT32_MAX ? UINT32_MAX : param};
+	return {state, param > UINT32_MAX ? UINT32_MAX : uint32_t(param)};
 }
diff --git a/src/gfx/pal_spec.cpp b/src/gfx/pal_spec.cpp
index b8b08704..32d3cdd1 100644
--- a/src/gfx/pal_spec.cpp
+++ b/src/gfx/pal_spec.cpp
@@ -204,7 +204,7 @@ static void warnExtraColors(
 // Parses the initial part of a string_view, advancing the "read index" as it does
 template<typename UintT> // Should be uint*_t
 static std::optional<UintT> parseDec(std::string const &str, size_t &n) {
-	uintmax_t value = 0;
+	UintT value = 0;
 	auto result = std::from_chars(str.data() + n, str.data() + str.length(), value);
 	if (static_cast<bool>(result.ec)) {
 		return std::nullopt;