diff --git a/src/util/OptionParser.cxx b/src/util/OptionParser.cxx
index 30dcc1585..b211cfb3c 100644
--- a/src/util/OptionParser.cxx
+++ b/src/util/OptionParser.cxx
@@ -22,6 +22,14 @@
 #include "util/RuntimeError.hxx"
 #include "util/StringCompare.hxx"
 
+static const char *
+Shift(std::span<const char *const> &s) noexcept
+{
+	const char *value = s.front();
+	s = s.subspan(1);
+	return value;
+}
+
 inline const char *
 OptionParser::CheckShiftValue(const char *s, const OptionDef &option)
 {
@@ -31,7 +39,7 @@ OptionParser::CheckShiftValue(const char *s, const OptionDef &option)
 	if (args.empty())
 		throw FormatRuntimeError("Value expected after %s", s);
 
-	return args.shift();
+	return Shift(args);
 }
 
 inline OptionParser::Result
@@ -58,14 +66,14 @@ OptionParser::IdentifyOption(const char *s)
 			else
 				continue;
 
-			return {int(&i - options.data), value};
+			return {int(&i - options.data()), value};
 		}
 	} else if (s[1] != 0 && s[2] == 0) {
 		const char ch = s[1];
 		for (const auto &i : options) {
 			if (i.HasShortOption() && ch == i.GetShortOption()) {
 				const char *value = CheckShiftValue(s, i);
-				return {int(&i - options.data), value};
+				return {int(&i - options.data()), value};
 			}
 		}
 	}
@@ -77,7 +85,7 @@ OptionParser::Result
 OptionParser::Next()
 {
 	while (!args.empty()) {
-		const char *arg = args.shift();
+		const char *arg = Shift(args);
 		if (arg[0] == '-')
 			return IdentifyOption(arg);
 
diff --git a/src/util/OptionParser.hxx b/src/util/OptionParser.hxx
index 8371fa76f..e687bdf3c 100644
--- a/src/util/OptionParser.hxx
+++ b/src/util/OptionParser.hxx
@@ -20,18 +20,18 @@
 #ifndef MPD_UTIL_OPTIONPARSER_HXX
 #define MPD_UTIL_OPTIONPARSER_HXX
 
-#include "util/ConstBuffer.hxx"
+#include "OptionDef.hxx"
 
-class OptionDef;
+#include <span>
 
 /**
  * Command line option parser.
  */
 class OptionParser
 {
-	ConstBuffer<OptionDef> options;
+	std::span<const OptionDef> options;
 
-	ConstBuffer<const char *> args;
+	std::span<const char *const> args;
 
 	const char **const remaining_head, **remaining_tail;
 
@@ -39,7 +39,7 @@ public:
 	/**
 	 * Constructs #OptionParser.
 	 */
-	OptionParser(ConstBuffer<OptionDef> _options,
+	OptionParser(std::span<const OptionDef> _options,
 		     int _argc, char **_argv) noexcept
 		:options(_options), args(_argv + 1, _argc - 1),
 		 remaining_head(const_cast<const char **>(_argv + 1)),
@@ -66,7 +66,7 @@ public:
 	/**
 	 * Returns the remaining non-option arguments.
 	 */
-	ConstBuffer<const char *> GetRemaining() const noexcept {
+	std::span<const char *const> GetRemaining() const noexcept {
 		return {remaining_head, remaining_tail};
 	}
 
diff --git a/test/RunChromaprint.cxx b/test/RunChromaprint.cxx
index c54a62185..d1869847a 100644
--- a/test/RunChromaprint.cxx
+++ b/test/RunChromaprint.cxx
@@ -79,7 +79,7 @@ ParseCommandLine(int argc, char **argv)
 	}
 
 	auto args = option_parser.GetRemaining();
-	if (args.size != 2)
+	if (args.size() != 2)
 		throw std::runtime_error("Usage: RunChromaprint [--verbose] [--config=FILE] DECODER URI");
 
 	c.decoder = args[0];
diff --git a/test/run_convert.cxx b/test/run_convert.cxx
index 263522cf3..b0398bbcf 100644
--- a/test/run_convert.cxx
+++ b/test/run_convert.cxx
@@ -82,7 +82,7 @@ ParseCommandLine(int argc, char **argv)
 	}
 
 	auto args = option_parser.GetRemaining();
-	if (args.size != 2)
+	if (args.size() != 2)
 		throw std::runtime_error("Usage: run_convert IN_FORMAT OUT_FORMAT <IN >OUT");
 
 	c.in_audio_format = ParseAudioFormat(args[0], false);
diff --git a/test/run_decoder.cxx b/test/run_decoder.cxx
index cdfa852b4..64d1aa6c6 100644
--- a/test/run_decoder.cxx
+++ b/test/run_decoder.cxx
@@ -87,7 +87,7 @@ ParseCommandLine(int argc, char **argv)
 	}
 
 	auto args = option_parser.GetRemaining();
-	if (args.size != 2)
+	if (args.size() != 2)
 		throw std::runtime_error("Usage: run_decoder [--verbose] [--config=FILE] DECODER URI");
 
 	c.decoder = args[0];
diff --git a/test/run_input.cxx b/test/run_input.cxx
index 5fc1e044e..2077d88ec 100644
--- a/test/run_input.cxx
+++ b/test/run_input.cxx
@@ -124,7 +124,7 @@ ParseCommandLine(int argc, char **argv)
 	}
 
 	auto args = option_parser.GetRemaining();
-	if (args.size != 1)
+	if (args.size() != 1)
 		throw std::runtime_error("Usage: run_input [--verbose] [--config=FILE] [--scan] [--chunk-size=BYTES] URI");
 
 	c.uri = args.front();
diff --git a/test/run_output.cxx b/test/run_output.cxx
index e67ec25d3..53010bc2f 100644
--- a/test/run_output.cxx
+++ b/test/run_output.cxx
@@ -76,13 +76,13 @@ ParseCommandLine(int argc, char **argv)
 	}
 
 	auto args = option_parser.GetRemaining();
-	if (args.size < 2 || args.size > 3)
+	if (args.size() < 2 || args.size() > 3)
 		throw std::runtime_error("Usage: run_output CONFIG NAME [FORMAT] <IN");
 
 	c.config_path = args[0];
 	c.output_name = args[1];
 
-	if (args.size > 2)
+	if (args.size() > 2)
 		c.audio_format = ParseAudioFormat(args[2], false);
 
 	return c;