diff --git a/src/Algos.cc b/src/Algos.cc
index 11ddca5c0..1c0df8027 100644
--- a/src/Algos.cc
+++ b/src/Algos.cc
@@ -8,11 +8,12 @@
 #include <cctype>
 #include <memory>
 #include <string>
+#include <string_view>
 #include <thread>
 #include <utility>
 
 std::string
-toUpper(const StringRef str) noexcept {
+toUpper(const std::string_view str) noexcept {
   std::string res;
   for (const unsigned char c : str) {
     res += static_cast<char>(std::toupper(c));
@@ -21,7 +22,7 @@ toUpper(const StringRef str) noexcept {
 }
 
 std::string
-toMacroName(const StringRef name) noexcept {
+toMacroName(const std::string_view name) noexcept {
   std::string macroName;
   for (const unsigned char c : name) {
     if (std::isalpha(c)) {
@@ -36,7 +37,7 @@ toMacroName(const StringRef name) noexcept {
 }
 
 int
-execCmd(const StringRef cmd) noexcept {
+execCmd(const std::string_view cmd) noexcept {
   logger::debug("Running `", cmd, '`');
   const int status = std::system(cmd.data());
   const int exitCode = status >> 8;
@@ -44,7 +45,7 @@ execCmd(const StringRef cmd) noexcept {
 }
 
 static std::pair<std::string, int>
-getCmdOutputImpl(const StringRef cmd) {
+getCmdOutputImpl(const std::string_view cmd) {
   constexpr usize bufferSize = 128;
   std::array<char, bufferSize> buffer{};
   std::string output;
@@ -67,7 +68,7 @@ getCmdOutputImpl(const StringRef cmd) {
 }
 
 std::string
-getCmdOutput(const StringRef cmd, const usize retry) {
+getCmdOutput(const std::string_view cmd, const usize retry) {
   logger::debug("Running `", cmd, '`');
 
   int exitCode = EXIT_SUCCESS;
@@ -87,7 +88,7 @@ getCmdOutput(const StringRef cmd, const usize retry) {
 }
 
 bool
-commandExists(const StringRef cmd) noexcept {
+commandExists(const std::string_view cmd) noexcept {
   std::string checkCmd = "command -v ";
   checkCmd += cmd;
   checkCmd += " >/dev/null 2>&1";
@@ -96,7 +97,7 @@ commandExists(const StringRef cmd) noexcept {
 
 // ref: https://wandbox.org/permlink/zRjT41alOHdwcf00
 static usize
-levDistance(const StringRef lhs, const StringRef rhs) {
+levDistance(const std::string_view lhs, const std::string_view rhs) {
   const usize lhsSize = lhs.size();
   const usize rhsSize = rhs.size();
 
@@ -132,18 +133,22 @@ levDistance(const StringRef lhs, const StringRef rhs) {
 }
 
 static bool
-equalsInsensitive(const StringRef lhs, const StringRef rhs) noexcept {
+equalsInsensitive(
+    const std::string_view lhs, const std::string_view rhs
+) noexcept {
   return std::equal(
       lhs.cbegin(), lhs.cend(), rhs.cbegin(), rhs.cend(),
       [](char lhs, char rhs) { return std::tolower(lhs) == std::tolower(rhs); }
   );
 }
 
-Option<StringRef>
-findSimilarStr(const StringRef lhs, std::span<const StringRef> candidates) {
+Option<std::string_view>
+findSimilarStr(
+    const std::string_view lhs, std::span<const std::string_view> candidates
+) {
   // We need to check if `Candidates` has the exact case-insensitive string
   // because the Levenshtein distance match does not care about it.
-  for (const StringRef str : candidates) {
+  for (const std::string_view str : candidates) {
     if (equalsInsensitive(lhs, str)) {
       return str;
     }
@@ -155,8 +160,8 @@ findSimilarStr(const StringRef lhs, std::span<const StringRef> candidates) {
   const usize length = lhs.size();
   const usize maxDist = length < 3 ? length - 1 : length / 3;
 
-  Option<std::pair<StringRef, usize>> similarStr = None;
-  for (const StringRef str : candidates) {
+  Option<std::pair<std::string_view, usize>> similarStr = None;
+  for (const std::string_view str : candidates) {
     const usize curDist = levDistance(lhs, str);
     if (curDist <= maxDist) {
       // The first similar string found || More similar string found
@@ -192,9 +197,9 @@ testLevDistance() {
 
 void
 testLevDistance2() {
-  constexpr StringRef str1 = "\nMäry häd ä little lämb\n\nLittle lämb\n";
-  constexpr StringRef str2 = "\nMary häd ä little lämb\n\nLittle lämb\n";
-  constexpr StringRef str3 = "Mary häd ä little lämb\n\nLittle lämb\n";
+  constexpr std::string_view str1 = "\nMäry häd ä little lämb\n\nLittle lämb\n";
+  constexpr std::string_view str2 = "\nMary häd ä little lämb\n\nLittle lämb\n";
+  constexpr std::string_view str3 = "Mary häd ä little lämb\n\nLittle lämb\n";
 
   assertEq(levDistance(str1, str2), 2UL);
   assertEq(levDistance(str2, str1), 2UL);
@@ -221,9 +226,9 @@ testLevDistance2() {
 
 void
 testFindSimilarStr() {
-  constexpr Arr<StringRef, 8> candidates{
-    "if", "ifdef", "ifndef", "elif", "else", "endif", "elifdef", "elifndef"
-  };
+  constexpr Arr<std::string_view, 8> candidates{ "if",      "ifdef",   "ifndef",
+                                                 "elif",    "else",    "endif",
+                                                 "elifdef", "elifndef" };
 
   assertEq(findSimilarStr("id", candidates), "if"sv);
   assertEq(findSimilarStr("ifd", candidates), "if"sv);
@@ -245,11 +250,11 @@ testFindSimilarStr() {
 
 void
 testFindSimilarStr2() {
-  constexpr Arr<StringRef, 2> candidates{ "aaab", "aaabc" };
+  constexpr Arr<std::string_view, 2> candidates{ "aaab", "aaabc" };
   assertEq(findSimilarStr("aaaa", candidates), "aaab"sv);
   assertEq(findSimilarStr("1111111111", candidates), None);
 
-  constexpr Arr<StringRef, 1> candidateS2{ "AAAA" };
+  constexpr Arr<std::string_view, 1> candidateS2{ "AAAA" };
   assertEq(findSimilarStr("aaaa", candidateS2), "AAAA"sv);
 
   pass();
diff --git a/src/Algos.hpp b/src/Algos.hpp
index baae825dc..bdba75ab7 100644
--- a/src/Algos.hpp
+++ b/src/Algos.hpp
@@ -11,14 +11,15 @@
 #include <span>
 #include <sstream>
 #include <string>
+#include <string_view>
 #include <utility>
 
-std::string toUpper(StringRef str) noexcept;
-std::string toMacroName(StringRef name) noexcept;
+std::string toUpper(std::string_view str) noexcept;
+std::string toMacroName(std::string_view name) noexcept;
 
-int execCmd(StringRef cmd) noexcept;
-std::string getCmdOutput(StringRef cmd, usize retry = 3);
-bool commandExists(StringRef cmd) noexcept;
+int execCmd(std::string_view cmd) noexcept;
+std::string getCmdOutput(std::string_view cmd, usize retry = 3);
+bool commandExists(std::string_view cmd) noexcept;
 
 template <typename T>
 Vec<std::string>
@@ -83,5 +84,6 @@ topoSort(
 ///
 /// \returns a similar string if exists. If no similar string exists,
 /// returns None.
-Option<StringRef>
-findSimilarStr(StringRef lhs, std::span<const StringRef> candidates);
+Option<std::string_view> findSimilarStr(
+    std::string_view lhs, std::span<const std::string_view> candidates
+);
diff --git a/src/BuildConfig.cc b/src/BuildConfig.cc
index 6076c1a08..408d72c73 100644
--- a/src/BuildConfig.cc
+++ b/src/BuildConfig.cc
@@ -23,13 +23,14 @@
 #include <span>
 #include <sstream>
 #include <string>
+#include <string_view>
 #include <tbb/blocked_range.h>
 #include <tbb/parallel_for.h>
 #include <tbb/spin_mutex.h>
 #include <thread>
 
-static constinit const StringRef TEST_OUT_DIR = "tests";
-static constinit const StringRef PATH_FROM_OUT_DIR = "../../";
+static constinit const std::string_view TEST_OUT_DIR = "tests";
+static constinit const std::string_view PATH_FROM_OUT_DIR = "../../";
 
 // NOLINTBEGIN(cppcoreguidelines-avoid-non-const-global-variables)
 static std::string OUT_DIR;
@@ -57,7 +58,7 @@ getOutDir() {
 }
 
 static Vec<fs::path>
-listSourceFilePaths(const StringRef directory) {
+listSourceFilePaths(const std::string_view directory) {
   Vec<fs::path> sourceFilePaths;
   for (const auto& entry : fs::recursive_directory_iterator(directory)) {
     if (!SOURCE_FILE_EXTS.contains(entry.path().extension())) {
@@ -183,11 +184,11 @@ struct BuildConfig {
 
   void emitVariable(std::ostream& os, const std::string& varName) const;
   void emitMakefile(std::ostream& os) const;
-  void emitCompdb(StringRef baseDir, std::ostream& os) const;
+  void emitCompdb(std::string_view baseDir, std::ostream& os) const;
 };
 
 static void
-emitDep(std::ostream& os, usize& offset, const StringRef dep) {
+emitDep(std::ostream& os, usize& offset, const std::string_view dep) {
   constexpr usize maxLineLen = 80;
   if (offset + dep.size() + 2 > maxLineLen) { // 2 for space and \.
     // \ for line continuation. \ is the 80th character.
@@ -200,7 +201,7 @@ emitDep(std::ostream& os, usize& offset, const StringRef dep) {
 
 static void
 emitTarget(
-    std::ostream& os, const StringRef target,
+    std::ostream& os, const std::string_view target,
     const HashSet<std::string>& dependsOn,
     const Option<std::string>& sourceFile = None,
     const Vec<std::string>& commands = {}
@@ -213,12 +214,12 @@ emitTarget(
   if (sourceFile.has_value()) {
     emitDep(os, offset, sourceFile.value());
   }
-  for (const StringRef dep : dependsOn) {
+  for (const std::string_view dep : dependsOn) {
     emitDep(os, offset, dep);
   }
   os << '\n';
 
-  for (const StringRef cmd : commands) {
+  for (const std::string_view cmd : commands) {
     os << '\t';
     if (!cmd.starts_with('@')) {
       os << "$(Q)";
@@ -286,7 +287,8 @@ BuildConfig::emitMakefile(std::ostream& os) const {
 }
 
 void
-BuildConfig::emitCompdb(const StringRef baseDir, std::ostream& os) const {
+BuildConfig::emitCompdb(const std::string_view baseDir, std::ostream& os)
+    const {
   const fs::path baseDirPath = fs::canonical(baseDir);
   const std::string indent1(2, ' ');
   const std::string indent2(4, ' ');
@@ -299,7 +301,7 @@ BuildConfig::emitCompdb(const StringRef baseDir, std::ostream& os) const {
     }
 
     bool isCompileTarget = false;
-    for (const StringRef cmd : targetInfo.commands) {
+    for (const std::string_view cmd : targetInfo.commands) {
       if (!cmd.starts_with("$(CXX)") && !cmd.starts_with("@$(CXX)")) {
         continue;
       }
@@ -392,7 +394,7 @@ parseMMOutput(const std::string& mmOutput, std::string& target) {
 }
 
 static bool
-isUpToDate(const StringRef makefilePath) {
+isUpToDate(const std::string_view makefilePath) {
   if (!fs::exists(makefilePath)) {
     return false;
   }
@@ -443,7 +445,7 @@ containsTestCode(const std::string& sourceFile) {
 }
 
 static std::string
-printfCmd(const StringRef header, const StringRef body) {
+printfCmd(const std::string_view header, const std::string_view body) {
   std::ostringstream oss;
   logger::info(oss, header, body);
   std::string msg = oss.str();
@@ -513,7 +515,7 @@ mapHeaderToObj(const fs::path& headerPath, const fs::path& buildOutDir) {
 // depending header files for the source file.
 static void
 collectBinDepObjs( // NOLINT(misc-no-recursion)
-    HashSet<std::string>& deps, const StringRef sourceFileName,
+    HashSet<std::string>& deps, const std::string_view sourceFileName,
     const HashSet<std::string>& objTargetDeps,
     const HashSet<std::string>& buildObjTargets, const BuildConfig& config
 ) {
@@ -565,7 +567,7 @@ installDeps() {
 }
 
 static void
-addDefine(const StringRef name, const StringRef value) {
+addDefine(const std::string_view name, const std::string_view value) {
   DEFINES += fmt::format(" -D{}='\"{}\"'", name, value);
 }
 
@@ -586,7 +588,7 @@ setVariables(BuildConfig& config, const bool isDebug) {
   if (profile.lto) {
     CXXFLAGS += " -flto";
   }
-  for (const StringRef flag : profile.cxxflags) {
+  for (const std::string_view flag : profile.cxxflags) {
     CXXFLAGS += ' ';
     CXXFLAGS += flag;
   }
diff --git a/src/Cli.cc b/src/Cli.cc
index 356ded98a..001bb1e47 100644
--- a/src/Cli.cc
+++ b/src/Cli.cc
@@ -12,9 +12,10 @@
 #include <iomanip>
 #include <iostream>
 #include <string>
+#include <string_view>
 #include <utility>
 
-static constinit const StringRef PADDING = "  ";
+static constinit const std::string_view PADDING = "  ";
 
 static void
 setOffset(const usize offset) noexcept {
@@ -23,13 +24,14 @@ setOffset(const usize offset) noexcept {
 }
 
 static void
-printHeader(const StringRef header) noexcept {
+printHeader(const std::string_view header) noexcept {
   std::cout << bold(green(header)) << '\n';
 }
 
 static void
 printUsage(
-    const StringRef name, const StringRef cmd, const StringRef usage
+    const std::string_view name, const std::string_view cmd,
+    const std::string_view usage
 ) noexcept {
   std::cout << bold(green("Usage: ")) << bold(cyan(name)) << ' ';
   if (!cmd.empty()) {
@@ -43,7 +45,9 @@ printUsage(
 }
 
 void
-addOptCandidates(Vec<StringRef>& candidates, const Vec<Opt>& opts) noexcept {
+addOptCandidates(
+    Vec<std::string_view>& candidates, const Vec<Opt>& opts
+) noexcept {
   for (const auto& opt : opts) {
     candidates.push_back(opt.name);
     if (!opt.shortName.empty()) {
@@ -167,7 +171,7 @@ Subcmd::addOpt(Opt opt) noexcept {
   return *this;
 }
 Subcmd&
-Subcmd::setMainFn(std::function<int(std::span<const StringRef>)> mainFn
+Subcmd::setMainFn(std::function<int(std::span<const std::string_view>)> mainFn
 ) noexcept {
   this->mainFn = std::move(mainFn);
   return *this;
@@ -193,8 +197,8 @@ Subcmd::getUsage() const noexcept {
 }
 
 [[nodiscard]] int
-Subcmd::noSuchArg(StringRef arg) const {
-  Vec<StringRef> candidates;
+Subcmd::noSuchArg(std::string_view arg) const {
+  Vec<std::string_view> candidates;
   if (globalOpts.has_value()) {
     addOptCandidates(candidates, globalOpts.value());
   }
@@ -214,7 +218,7 @@ Subcmd::noSuchArg(StringRef arg) const {
 }
 
 [[nodiscard]] int
-Subcmd::missingArgumentForOpt(const StringRef arg) {
+Subcmd::missingArgumentForOpt(const std::string_view arg) {
   logger::error("Missing argument for `", arg, "`");
   return EXIT_FAILURE;
 }
@@ -310,13 +314,13 @@ Cli::addOpt(Opt opt) noexcept {
 }
 
 bool
-Cli::hasSubcmd(StringRef subcmd) const noexcept {
+Cli::hasSubcmd(std::string_view subcmd) const noexcept {
   return subcmds.contains(subcmd);
 }
 
 [[nodiscard]] int
-Cli::noSuchArg(StringRef arg) const {
-  Vec<StringRef> candidates;
+Cli::noSuchArg(std::string_view arg) const {
+  Vec<std::string_view> candidates;
   for (const auto& cmd : subcmds) {
     candidates.push_back(cmd.second.name);
     if (!cmd.second.shortName.empty()) {
@@ -339,12 +343,14 @@ Cli::noSuchArg(StringRef arg) const {
 }
 
 [[nodiscard]] int
-Cli::exec(const StringRef subcmd, const std::span<const StringRef> args) const {
+Cli::exec(
+    const std::string_view subcmd, const std::span<const std::string_view> args
+) const {
   return subcmds.at(subcmd).mainFn(args);
 }
 
 void
-Cli::printSubcmdHelp(const StringRef subcmd) const noexcept {
+Cli::printSubcmdHelp(const std::string_view subcmd) const noexcept {
   subcmds.at(subcmd).printHelp();
 }
 
@@ -441,7 +447,7 @@ Cli::printCmdHelp() const noexcept {
 }
 
 [[nodiscard]] int
-Cli::printHelp(const std::span<const StringRef> args) const noexcept {
+Cli::printHelp(const std::span<const std::string_view> args) const noexcept {
   // Parse args
   for (auto itr = args.begin(); itr != args.end(); ++itr) {
     if (const auto res = handleGlobalOpts(itr, args.end(), "help")) {
diff --git a/src/Cli.hpp b/src/Cli.hpp
index 4c4995228..dfe6935df 100644
--- a/src/Cli.hpp
+++ b/src/Cli.hpp
@@ -8,6 +8,7 @@
 #include <iterator>
 #include <span>
 #include <string>
+#include <string_view>
 
 class Opt;
 class Arg;
@@ -21,8 +22,8 @@ template <typename Derived>
 class CliBase {
 protected:
   // NOLINTBEGIN(cppcoreguidelines-non-private-member-variables-in-classes,misc-non-private-member-variables-in-classes)
-  StringRef name;
-  StringRef desc;
+  std::string_view name;
+  std::string_view desc;
   // NOLINTEND(cppcoreguidelines-non-private-member-variables-in-classes,misc-non-private-member-variables-in-classes)
 
 public:
@@ -33,8 +34,9 @@ class CliBase {
   constexpr CliBase& operator=(const CliBase&) noexcept = default;
   constexpr CliBase& operator=(CliBase&&) noexcept = default;
 
-  constexpr explicit CliBase(const StringRef name) noexcept : name(name) {}
-  constexpr Derived& setDesc(const StringRef desc) noexcept {
+  constexpr explicit CliBase(const std::string_view name) noexcept
+      : name(name) {}
+  constexpr Derived& setDesc(const std::string_view desc) noexcept {
     this->desc = desc;
     return static_cast<Derived&>(*this);
   }
@@ -44,12 +46,12 @@ template <typename Derived>
 class ShortAndHidden {
 protected:
   // NOLINTBEGIN(cppcoreguidelines-non-private-member-variables-in-classes,misc-non-private-member-variables-in-classes)
-  StringRef shortName;
+  std::string_view shortName;
   bool isHidden = false;
   // NOLINTEND(cppcoreguidelines-non-private-member-variables-in-classes,misc-non-private-member-variables-in-classes)
 
 public:
-  constexpr Derived& setShort(const StringRef shortName) noexcept {
+  constexpr Derived& setShort(const std::string_view shortName) noexcept {
     this->shortName = shortName;
     return static_cast<Derived&>(*this);
   }
@@ -63,26 +65,27 @@ class Opt : public CliBase<Opt>, public ShortAndHidden<Opt> {
   friend class Subcmd;
   friend class Cli;
 
-  StringRef placeholder;
-  StringRef defaultVal;
+  std::string_view placeholder;
+  std::string_view defaultVal;
   bool isGlobal = false;
 
 public:
   using CliBase::CliBase;
 
-  friend void
-  addOptCandidates(Vec<StringRef>& candidates, const Vec<Opt>& opts) noexcept;
+  friend void addOptCandidates(
+      Vec<std::string_view>& candidates, const Vec<Opt>& opts
+  ) noexcept;
   friend usize calcOptMaxShortSize(const Vec<Opt>& opts) noexcept;
   friend usize
   calcOptMaxOffset(const Vec<Opt>& opts, usize maxShortSize) noexcept;
   friend void
   printOpts(const Vec<Opt>& opts, usize maxShortSize, usize maxOffset) noexcept;
 
-  constexpr Opt& setPlaceholder(const StringRef placeholder) noexcept {
+  constexpr Opt& setPlaceholder(const std::string_view placeholder) noexcept {
     this->placeholder = placeholder;
     return *this;
   }
-  constexpr Opt& setDefault(const StringRef defaultVal) noexcept {
+  constexpr Opt& setDefault(const std::string_view defaultVal) noexcept {
     this->defaultVal = defaultVal;
     return *this;
   }
@@ -136,11 +139,11 @@ class Arg : public CliBase<Arg> {
 class Subcmd : public CliBase<Subcmd>, public ShortAndHidden<Subcmd> {
   friend class Cli;
 
-  StringRef cmdName;
+  std::string_view cmdName;
   Option<Vec<Opt>> globalOpts = None;
   Vec<Opt> localOpts;
   Arg arg;
-  std::function<int(std::span<const StringRef>)> mainFn;
+  std::function<int(std::span<const std::string_view>)> mainFn;
 
 public:
   using CliBase::CliBase;
@@ -151,16 +154,16 @@ class Subcmd : public CliBase<Subcmd>, public ShortAndHidden<Subcmd> {
   }
 
   Subcmd& addOpt(Opt opt) noexcept;
-  Subcmd& setMainFn(std::function<int(std::span<const StringRef>)> mainFn
+  Subcmd& setMainFn(std::function<int(std::span<const std::string_view>)> mainFn
   ) noexcept;
-  [[nodiscard]] int noSuchArg(StringRef arg) const;
-  [[nodiscard]] static int missingArgumentForOpt(StringRef arg);
+  [[nodiscard]] int noSuchArg(std::string_view arg) const;
+  [[nodiscard]] static int missingArgumentForOpt(std::string_view arg);
 
 private:
   constexpr bool hasShort() const noexcept {
     return !shortName.empty();
   }
-  constexpr Subcmd& setCmdName(StringRef cmdName) noexcept {
+  constexpr Subcmd& setCmdName(std::string_view cmdName) noexcept {
     this->cmdName = cmdName;
     return *this;
   }
@@ -177,7 +180,7 @@ class Subcmd : public CliBase<Subcmd>, public ShortAndHidden<Subcmd> {
 };
 
 class Cli : public CliBase<Cli> {
-  HashMap<StringRef, Subcmd> subcmds;
+  HashMap<std::string_view, Subcmd> subcmds;
   Vec<Opt> globalOpts;
   Vec<Opt> localOpts;
 
@@ -186,13 +189,14 @@ class Cli : public CliBase<Cli> {
 
   Cli& addSubcmd(const Subcmd& subcmd) noexcept;
   Cli& addOpt(Opt opt) noexcept;
-  bool hasSubcmd(StringRef subcmd) const noexcept;
+  bool hasSubcmd(std::string_view subcmd) const noexcept;
 
-  [[nodiscard]] int noSuchArg(StringRef arg) const;
+  [[nodiscard]] int noSuchArg(std::string_view arg) const;
   [[nodiscard]] int
-  exec(StringRef subcmd, std::span<const StringRef> args) const;
-  void printSubcmdHelp(StringRef subcmd) const noexcept;
-  [[nodiscard]] int printHelp(std::span<const StringRef> args) const noexcept;
+  exec(std::string_view subcmd, std::span<const std::string_view> args) const;
+  void printSubcmdHelp(std::string_view subcmd) const noexcept;
+  [[nodiscard]] int printHelp(std::span<const std::string_view> args
+  ) const noexcept;
   usize calcMaxOffset(usize maxShortSize) const noexcept;
   void printAllSubcmds(bool showHidden, usize maxOffset = 0) const noexcept;
 
@@ -204,7 +208,7 @@ class Cli : public CliBase<Cli> {
   // TODO: result-like types make more sense.
   [[nodiscard]] static inline Option<int> handleGlobalOpts(
       std::forward_iterator auto& itr, const std::forward_iterator auto end,
-      StringRef subcmd = ""
+      std::string_view subcmd = ""
   ) {
     if (*itr == "-h"sv || *itr == "--help"sv) {
       if (!subcmd.empty()) {
diff --git a/src/Cmd/Add.cc b/src/Cmd/Add.cc
index efac2b8e3..c7cee2f76 100644
--- a/src/Cmd/Add.cc
+++ b/src/Cmd/Add.cc
@@ -9,9 +9,10 @@
 #include <fstream>
 #include <functional>
 #include <string>
+#include <string_view>
 #include <toml.hpp>
 
-static int addMain(std::span<const StringRef> args);
+static int addMain(std::span<const std::string_view> args);
 
 const Subcmd ADD_CMD =
     Subcmd{ "add" }
@@ -37,8 +38,8 @@ const Subcmd ADD_CMD =
 
 static Option<int>
 handleNextArg(
-    std::span<const StringRef>::iterator& itr,
-    const std::span<const StringRef>::iterator& end, std::string& arg
+    std::span<const std::string_view>::iterator& itr,
+    const std::span<const std::string_view>::iterator& end, std::string& arg
 ) {
   ++itr;
   if (itr == end) {
@@ -49,7 +50,9 @@ handleNextArg(
 }
 
 static void
-handleDependency(HashSet<StringRef>& newDeps, const StringRef dep) {
+handleDependency(
+    HashSet<std::string_view>& newDeps, const std::string_view dep
+) {
   if (newDeps.contains(dep)) {
     logger::warn("The dependency `", dep, "` is already in the poac.toml");
     return;
@@ -58,7 +61,7 @@ handleDependency(HashSet<StringRef>& newDeps, const StringRef dep) {
 }
 
 static std::string
-getDependencyGitUrl(const StringRef dep) {
+getDependencyGitUrl(const std::string_view dep) {
   if (dep.find("://") == std::string::npos) {
     // check if atleast in "user/repo" format
     if (dep.find('/') == std::string::npos) {
@@ -72,7 +75,7 @@ getDependencyGitUrl(const StringRef dep) {
 }
 
 static std::string
-getDependencyName(const StringRef dep) {
+getDependencyName(const std::string_view dep) {
   std::string name;
   if (dep.find("://") == std::string::npos) {
     name = dep.substr(dep.find_last_of('/') + 1);
@@ -92,7 +95,7 @@ getDependencyName(const StringRef dep) {
 
 static int
 addDependencyToManifest(
-    const HashSet<StringRef>& newDeps, bool isSystemDependency,
+    const HashSet<std::string_view>& newDeps, bool isSystemDependency,
     std::string& version, std::string& tag, std::string& rev,
     std::string& branch
 ) {
@@ -146,13 +149,13 @@ addDependencyToManifest(
 }
 
 static int
-addMain(const std::span<const StringRef> args) {
+addMain(const std::span<const std::string_view> args) {
   if (args.empty()) {
     logger::error("No dependencies to add");
     return EXIT_FAILURE;
   }
 
-  HashSet<StringRef> newDeps = {};
+  HashSet<std::string_view> newDeps = {};
 
   bool isSystemDependency = false;
   std::string version; // Only used with system-dependencies
@@ -163,7 +166,7 @@ addMain(const std::span<const StringRef> args) {
 
   // clang-format off
   HashMap<
-    StringRef,
+    std::string_view,
     std::function<Option<int>(decltype(args)::iterator&, decltype(args)::iterator)>
   >
   handlers = {
diff --git a/src/Cmd/Build.cc b/src/Cmd/Build.cc
index 54e0f1346..f90e12125 100644
--- a/src/Cmd/Build.cc
+++ b/src/Cmd/Build.cc
@@ -10,8 +10,9 @@
 #include <cstdlib>
 #include <span>
 #include <string>
+#include <string_view>
 
-static int buildMain(std::span<const StringRef> args);
+static int buildMain(std::span<const std::string_view> args);
 
 const Subcmd BUILD_CMD =
     Subcmd{ "build" }
@@ -45,7 +46,7 @@ buildImpl(std::string& outDir, const bool isDebug) {
 }
 
 static int
-buildMain(const std::span<const StringRef> args) {
+buildMain(const std::span<const std::string_view> args) {
   // Parse args
   bool isDebug = true;
   bool buildCompdb = false;
diff --git a/src/Cmd/Clean.cc b/src/Cmd/Clean.cc
index 002f64ea1..dc2e335fa 100644
--- a/src/Cmd/Clean.cc
+++ b/src/Cmd/Clean.cc
@@ -6,8 +6,9 @@
 #include <cstdlib>
 #include <span>
 #include <string>
+#include <string_view>
 
-static int cleanMain(std::span<const StringRef> args) noexcept;
+static int cleanMain(std::span<const std::string_view> args) noexcept;
 
 const Subcmd CLEAN_CMD = //
     Subcmd{ "clean" }
@@ -19,7 +20,7 @@ const Subcmd CLEAN_CMD = //
         .setMainFn(cleanMain);
 
 static int
-cleanMain(const std::span<const StringRef> args) noexcept {
+cleanMain(const std::span<const std::string_view> args) noexcept {
   fs::path outDir = "poac-out"; // TODO: share across sources
 
   // Parse args
diff --git a/src/Cmd/Fmt.cc b/src/Cmd/Fmt.cc
index a24d99918..276470db8 100644
--- a/src/Cmd/Fmt.cc
+++ b/src/Cmd/Fmt.cc
@@ -13,8 +13,9 @@
 #include <fstream>
 #include <span>
 #include <string>
+#include <string_view>
 
-static int fmtMain(std::span<const StringRef> args);
+static int fmtMain(std::span<const std::string_view> args);
 
 const Subcmd FMT_CMD =
     Subcmd{ "fmt" }
@@ -63,7 +64,7 @@ collectFormatTargetFiles(
 }
 
 static int
-fmtMain(const std::span<const StringRef> args) {
+fmtMain(const std::span<const std::string_view> args) {
   bool isCheck = false;
   // Parse args
   for (auto itr = args.begin(); itr != args.end(); ++itr) {
@@ -88,7 +89,7 @@ fmtMain(const std::span<const StringRef> args) {
     return EXIT_FAILURE;
   }
 
-  const StringRef packageName = getPackageName();
+  const std::string_view packageName = getPackageName();
   std::string clangFormatArgs = "--style=file --fallback-style=LLVM -Werror";
   if (isVerbose()) {
     clangFormatArgs += " --verbose";
diff --git a/src/Cmd/Help.cc b/src/Cmd/Help.cc
index dc0565697..04ad1a06c 100644
--- a/src/Cmd/Help.cc
+++ b/src/Cmd/Help.cc
@@ -1,11 +1,11 @@
 #include "Help.hpp"
 
 #include "../Cli.hpp"
-#include "../Rustify.hpp"
 
 #include <span>
+#include <string_view>
 
-static int helpMain(std::span<const StringRef> args) noexcept;
+static int helpMain(std::span<const std::string_view> args) noexcept;
 
 const Subcmd HELP_CMD = //
     Subcmd{ "help" }
@@ -14,6 +14,6 @@ const Subcmd HELP_CMD = //
         .setMainFn(helpMain);
 
 static int
-helpMain(const std::span<const StringRef> args) noexcept {
+helpMain(const std::span<const std::string_view> args) noexcept {
   return getCli().printHelp(args);
 }
diff --git a/src/Cmd/Init.cc b/src/Cmd/Init.cc
index 42d36f87c..e014ce215 100644
--- a/src/Cmd/Init.cc
+++ b/src/Cmd/Init.cc
@@ -10,8 +10,9 @@
 #include <fstream>
 #include <span>
 #include <string>
+#include <string_view>
 
-static int initMain(std::span<const StringRef> args);
+static int initMain(std::span<const std::string_view> args);
 
 const Subcmd INIT_CMD =
     Subcmd{ "init" }
@@ -21,7 +22,7 @@ const Subcmd INIT_CMD =
         .setMainFn(initMain);
 
 static int
-initMain(const std::span<const StringRef> args) {
+initMain(const std::span<const std::string_view> args) {
   // Parse args
   bool isBin = true;
   for (auto itr = args.begin(); itr != args.end(); ++itr) {
diff --git a/src/Cmd/Lint.cc b/src/Cmd/Lint.cc
index fb1c0cfe8..edf90cb15 100644
--- a/src/Cmd/Lint.cc
+++ b/src/Cmd/Lint.cc
@@ -10,8 +10,9 @@
 #include <fstream>
 #include <span>
 #include <string>
+#include <string_view>
 
-static int lintMain(std::span<const StringRef> args);
+static int lintMain(std::span<const std::string_view> args);
 
 const Subcmd LINT_CMD =
     Subcmd{ "lint" }
@@ -24,7 +25,7 @@ struct LintArgs {
 };
 
 static int
-lint(const StringRef name, const StringRef cpplintArgs) {
+lint(const std::string_view name, const std::string_view cpplintArgs) {
   logger::info("Linting", name);
 
   std::string cpplintCmd = "cpplint";
@@ -52,7 +53,7 @@ lint(const StringRef name, const StringRef cpplintArgs) {
 }
 
 static int
-lintMain(const std::span<const StringRef> args) {
+lintMain(const std::span<const std::string_view> args) {
   LintArgs lintArgs;
   for (auto itr = args.begin(); itr != args.end(); ++itr) {
     if (const auto res = Cli::handleGlobalOpts(itr, args.end(), "lint")) {
@@ -82,7 +83,7 @@ lintMain(const std::span<const StringRef> args) {
   }
 
   std::string cpplintArgs = lintArgs.excludes;
-  const StringRef packageName = getPackageName();
+  const std::string_view packageName = getPackageName();
   if (fs::exists("CPPLINT.cfg")) {
     logger::debug("Using CPPLINT.cfg for lint ...");
     return lint(packageName, cpplintArgs);
@@ -98,7 +99,7 @@ lintMain(const std::span<const StringRef> args) {
   if (!cpplintFilters.empty()) {
     logger::debug("Using Poac manifest file for lint ...");
     cpplintArgs += " --filter=";
-    for (const StringRef filter : cpplintFilters) {
+    for (const std::string_view filter : cpplintFilters) {
       cpplintArgs += filter;
       cpplintArgs += ',';
     }
diff --git a/src/Cmd/New.cc b/src/Cmd/New.cc
index b94745416..71bfd7833 100644
--- a/src/Cmd/New.cc
+++ b/src/Cmd/New.cc
@@ -16,8 +16,9 @@
 #include <iterator>
 #include <span>
 #include <string>
+#include <string_view>
 
-static int newMain(std::span<const StringRef> args);
+static int newMain(std::span<const std::string_view> args);
 
 const Subcmd NEW_CMD = //
     Subcmd{ "new" }
@@ -27,7 +28,7 @@ const Subcmd NEW_CMD = //
         .setArg(Arg{ "name" })
         .setMainFn(newMain);
 
-static constexpr StringRef MAIN_CC =
+static constexpr std::string_view MAIN_CC =
     "#include <iostream>\n\n"
     "int main() {\n"
     "  std::cout << \"Hello, world!\" << std::endl;\n"
@@ -47,7 +48,7 @@ getAuthor() noexcept {
 }
 
 std::string
-createPoacToml(const StringRef projectName) noexcept {
+createPoacToml(const std::string_view projectName) noexcept {
   std::string poacToml =
       "[package]\n"
       "name = \"";
@@ -64,7 +65,7 @@ createPoacToml(const StringRef projectName) noexcept {
 }
 
 static std::string
-getHeader(const StringRef projectName) noexcept {
+getHeader(const std::string_view projectName) noexcept {
   const std::string projectNameUpper = toMacroName(projectName);
   std::string header = "#ifndef " + projectNameUpper + "_HPP\n"
                   "#define " + projectNameUpper + "_HPP\n\n"
@@ -78,7 +79,9 @@ getHeader(const StringRef projectName) noexcept {
 }
 
 static void
-writeToFile(std::ofstream& ofs, const fs::path& fpath, const StringRef text) {
+writeToFile(
+    std::ofstream& ofs, const fs::path& fpath, const std::string_view text
+) {
   ofs.open(fpath);
   if (ofs.is_open()) {
     ofs << text;
@@ -92,7 +95,7 @@ writeToFile(std::ofstream& ofs, const fs::path& fpath, const StringRef text) {
 }
 
 static void
-createTemplateFiles(const bool isBin, const StringRef projectName) {
+createTemplateFiles(const bool isBin, const std::string_view projectName) {
   std::ofstream ofs;
 
   if (isBin) {
@@ -122,7 +125,7 @@ createTemplateFiles(const bool isBin, const StringRef projectName) {
 }
 
 static int
-newMain(const std::span<const StringRef> args) {
+newMain(const std::span<const std::string_view> args) {
   // Parse args
   bool isBin = true;
   std::string packageName;
diff --git a/src/Cmd/New.hpp b/src/Cmd/New.hpp
index 3a039fd9a..a509e50ea 100644
--- a/src/Cmd/New.hpp
+++ b/src/Cmd/New.hpp
@@ -1,9 +1,9 @@
 #pragma once
 
 #include "../Cli.hpp"
-#include "../Rustify.hpp"
 
 #include <string>
+#include <string_view>
 
 extern const Subcmd NEW_CMD;
-std::string createPoacToml(StringRef projectName) noexcept;
+std::string createPoacToml(std::string_view projectName) noexcept;
diff --git a/src/Cmd/Run.cc b/src/Cmd/Run.cc
index a843d571c..832ff739c 100644
--- a/src/Cmd/Run.cc
+++ b/src/Cmd/Run.cc
@@ -13,8 +13,9 @@
 #include <cstdlib>
 #include <span>
 #include <string>
+#include <string_view>
 
-static int runMain(std::span<const StringRef> args);
+static int runMain(std::span<const std::string_view> args);
 
 const Subcmd RUN_CMD =
     Subcmd{ "run" }
@@ -30,7 +31,7 @@ const Subcmd RUN_CMD =
         .setMainFn(runMain);
 
 static int
-runMain(const std::span<const StringRef> args) {
+runMain(const std::span<const std::string_view> args) {
   // Parse args
   bool isDebug = true;
   auto itr = args.begin();
diff --git a/src/Cmd/Search.cc b/src/Cmd/Search.cc
index 973d1d241..2a4fc93c0 100644
--- a/src/Cmd/Search.cc
+++ b/src/Cmd/Search.cc
@@ -11,8 +11,9 @@
 #include <nlohmann/json.hpp>
 #include <span>
 #include <string>
+#include <string_view>
 
-static int searchMain(std::span<const StringRef> args);
+static int searchMain(std::span<const std::string_view> args);
 
 const Subcmd SEARCH_CMD =
     Subcmd{ "search" }
@@ -94,7 +95,7 @@ printTable(const nlohmann::json& packages) {
 }
 
 static int
-searchMain(const std::span<const StringRef> args) {
+searchMain(const std::span<const std::string_view> args) {
   SearchArgs searchArgs;
   for (auto itr = args.begin(); itr != args.end(); ++itr) {
     if (const auto res = Cli::handleGlobalOpts(itr, args.end(), "search")) {
diff --git a/src/Cmd/Test.cc b/src/Cmd/Test.cc
index 98faa7a83..2d35d3a68 100644
--- a/src/Cmd/Test.cc
+++ b/src/Cmd/Test.cc
@@ -12,8 +12,9 @@
 #include <cstdlib>
 #include <span>
 #include <string>
+#include <string_view>
 
-static int testMain(std::span<const StringRef> args);
+static int testMain(std::span<const std::string_view> args);
 
 const Subcmd TEST_CMD = //
     Subcmd{ "test" }
@@ -25,7 +26,7 @@ const Subcmd TEST_CMD = //
         .setMainFn(testMain);
 
 static int
-testMain(const std::span<const StringRef> args) {
+testMain(const std::span<const std::string_view> args) {
   // Parse args
   bool isDebug = true;
   for (auto itr = args.begin(); itr != args.end(); ++itr) {
diff --git a/src/Cmd/Tidy.cc b/src/Cmd/Tidy.cc
index 3dc56a29b..8372158c3 100644
--- a/src/Cmd/Tidy.cc
+++ b/src/Cmd/Tidy.cc
@@ -12,8 +12,9 @@
 #include <cstdlib>
 #include <span>
 #include <string>
+#include <string_view>
 
-static int tidyMain(std::span<const StringRef> args);
+static int tidyMain(std::span<const std::string_view> args);
 
 const Subcmd TIDY_CMD =
     Subcmd{ "tidy" }
@@ -23,7 +24,7 @@ const Subcmd TIDY_CMD =
         .setMainFn(tidyMain);
 
 static int
-tidyImpl(const StringRef makeCmd) {
+tidyImpl(const std::string_view makeCmd) {
   const auto start = std::chrono::steady_clock::now();
 
   const int exitCode = execCmd(makeCmd);
@@ -38,7 +39,7 @@ tidyImpl(const StringRef makeCmd) {
 }
 
 static int
-tidyMain(const std::span<const StringRef> args) {
+tidyMain(const std::span<const std::string_view> args) {
   // Parse args
   bool fix = false;
   for (auto itr = args.begin(); itr != args.end(); ++itr) {
diff --git a/src/Cmd/Version.cc b/src/Cmd/Version.cc
index 022d048d4..dd34c4aa8 100644
--- a/src/Cmd/Version.cc
+++ b/src/Cmd/Version.cc
@@ -9,6 +9,7 @@
 #include <cstdlib>
 #include <iostream>
 #include <span>
+#include <string_view>
 
 #ifndef POAC_PKG_VERSION
 #  error "POAC_PKG_VERSION is not defined"
@@ -28,24 +29,24 @@ const Subcmd VERSION_CMD = //
         .setDesc("Show version information")
         .setMainFn(versionMain);
 
-static consteval StringRef
-checkAvailability(const StringRef str) noexcept {
+static consteval std::string_view
+checkAvailability(const std::string_view str) noexcept {
   return str.empty() ? "unavailable" : str;
 }
 
-static constinit const StringRef COMMIT_SHORT_HASH =
+static constinit const std::string_view COMMIT_SHORT_HASH =
     checkAvailability(POAC_COMMIT_SHORT_HASH);
-static constinit const StringRef COMMIT_HASH =
+static constinit const std::string_view COMMIT_HASH =
     checkAvailability(POAC_COMMIT_HASH);
-static constinit const StringRef COMMIT_DATE =
+static constinit const std::string_view COMMIT_DATE =
     checkAvailability(POAC_COMMIT_DATE);
 
 static consteval char
-firstMonthChar(const StringRef month) noexcept {
+firstMonthChar(const std::string_view month) noexcept {
   return (month[0] == 'O' || month[0] == 'N' || month[0] == 'D') ? '1' : '0';
 }
 static consteval char
-secondMonthChar(const StringRef month) noexcept {
+secondMonthChar(const std::string_view month) noexcept {
   if (month[0] == 'J') {
     if (month[1] == 'a') {
       // Jan
@@ -113,7 +114,7 @@ static constinit const char COMPILE_DATE[] = {
 };
 
 int
-versionMain(const std::span<const StringRef> args) noexcept {
+versionMain(const std::span<const std::string_view> args) noexcept {
   // Parse args
   for (auto itr = args.begin(); itr != args.end(); ++itr) {
     if (const auto res = Cli::handleGlobalOpts(itr, args.end(), "version")) {
diff --git a/src/Cmd/Version.hpp b/src/Cmd/Version.hpp
index c98e91b21..c896aeb7d 100644
--- a/src/Cmd/Version.hpp
+++ b/src/Cmd/Version.hpp
@@ -1,9 +1,9 @@
 #pragma once
 
 #include "../Cli.hpp"
-#include "../Rustify.hpp"
 
 #include <span>
+#include <string_view>
 
 extern const Subcmd VERSION_CMD;
-int versionMain(std::span<const StringRef> args) noexcept;
+int versionMain(std::span<const std::string_view> args) noexcept;
diff --git a/src/Git2/Config.cc b/src/Git2/Config.cc
index c255ecafe..d337544a3 100644
--- a/src/Git2/Config.cc
+++ b/src/Git2/Config.cc
@@ -1,9 +1,9 @@
 #include "Config.hpp"
 
-#include "../Rustify.hpp"
 #include "Exception.hpp"
 
 #include <string>
+#include <string_view>
 
 namespace git2 {
 
@@ -24,7 +24,7 @@ Config::openDefault() {
 }
 
 std::string
-Config::getString(const StringRef name) {
+Config::getString(const std::string_view name) {
   git_buf ret = { nullptr, 0, 0 };
   git2Throw(git_config_get_string_buf(&ret, this->raw, name.data()));
   return { ret.ptr, ret.size };
diff --git a/src/Git2/Config.hpp b/src/Git2/Config.hpp
index 1dc2b6c1c..d288dbf97 100644
--- a/src/Git2/Config.hpp
+++ b/src/Git2/Config.hpp
@@ -1,10 +1,10 @@
 #pragma once
 
-#include "../Rustify.hpp"
 #include "Global.hpp"
 
 #include <git2/config.h>
 #include <string>
+#include <string_view>
 
 namespace git2 {
 
@@ -27,7 +27,7 @@ struct Config : public GlobalState {
   Config& openDefault();
 
   /// Get the value of a string config variable as an owned string.
-  std::string getString(StringRef name);
+  std::string getString(std::string_view name);
 };
 
 } // end namespace git2
diff --git a/src/Git2/Describe.cc b/src/Git2/Describe.cc
index 790356730..4bfd79aba 100644
--- a/src/Git2/Describe.cc
+++ b/src/Git2/Describe.cc
@@ -1,11 +1,11 @@
 #include "Describe.hpp"
 
-#include "../Rustify.hpp"
 #include "Exception.hpp"
 #include "Repository.hpp"
 
 #include <git2/describe.h>
 #include <string>
+#include <string_view>
 
 namespace git2 {
 
@@ -52,7 +52,7 @@ DescribeOptions::showCommitOidAsFallback(const bool show) {
 }
 
 DescribeOptions&
-DescribeOptions::pattern(const StringRef pattern) {
+DescribeOptions::pattern(const std::string_view pattern) {
   this->raw.pattern = pattern.data();
   return *this;
 }
@@ -82,7 +82,7 @@ DescribeFormatOptions::alwaysUseLongFormat(const bool long_f) {
 }
 
 DescribeFormatOptions&
-DescribeFormatOptions::dirtySuffix(const StringRef suffix) {
+DescribeFormatOptions::dirtySuffix(const std::string_view suffix) {
   this->raw.dirty_suffix = suffix.data();
   return *this;
 }
diff --git a/src/Git2/Describe.hpp b/src/Git2/Describe.hpp
index 5892db16b..c64c6f1cd 100644
--- a/src/Git2/Describe.hpp
+++ b/src/Git2/Describe.hpp
@@ -1,11 +1,11 @@
 #pragma once
 
-#include "../Rustify.hpp"
 #include "Global.hpp"
 #include "Repository.hpp"
 
 #include <git2/describe.h>
 #include <string>
+#include <string_view>
 
 namespace git2 {
 
@@ -41,7 +41,7 @@ struct DescribeOptions : public GlobalState {
   /// back to showing the full id of the commit.
   DescribeOptions& showCommitOidAsFallback(bool show);
 
-  DescribeOptions& pattern(StringRef pattern);
+  DescribeOptions& pattern(std::string_view pattern);
 };
 
 struct DescribeFormatOptions : public GlobalState {
@@ -67,7 +67,7 @@ struct DescribeFormatOptions : public GlobalState {
 
   /// If the workdir is dirty and this is set, this string will be appended to
   /// the description string.
-  DescribeFormatOptions& dirtySuffix(StringRef suffix);
+  DescribeFormatOptions& dirtySuffix(std::string_view suffix);
 };
 
 struct Describe : public GlobalState {
diff --git a/src/Git2/Oid.cc b/src/Git2/Oid.cc
index 9d0a459d3..48e6c9a8e 100644
--- a/src/Git2/Oid.cc
+++ b/src/Git2/Oid.cc
@@ -1,12 +1,12 @@
 #include "Oid.hpp"
 
-#include "../Rustify.hpp"
 #include "Exception.hpp"
 
 #include <cstring>
 #include <git2/oid.h>
 #include <ostream>
 #include <string>
+#include <string_view>
 
 namespace git2 {
 
@@ -17,7 +17,7 @@ Oid::Oid(git_oid* oid) : oid(*oid), raw(oid) {}
 // NOLINTNEXTLINE(cppcoreguidelines-pro-type-const-cast)
 Oid::Oid(const git_oid* oid) : Oid(const_cast<git_oid*>(oid)) {}
 
-Oid::Oid(const StringRef str) {
+Oid::Oid(const std::string_view str) {
   git2Throw(git_oid_fromstrn(raw, str.data(), str.size()));
 }
 
diff --git a/src/Git2/Oid.hpp b/src/Git2/Oid.hpp
index f34f27859..1dbe28dce 100644
--- a/src/Git2/Oid.hpp
+++ b/src/Git2/Oid.hpp
@@ -6,6 +6,7 @@
 #include <git2/oid.h>
 #include <ostream>
 #include <string>
+#include <string_view>
 
 namespace git2 {
 
@@ -23,7 +24,7 @@ struct Oid : public GlobalState {
   explicit Oid(const git_oid* oid);
 
   /// Parse a hex-formatted object id into an oid structure.
-  explicit Oid(StringRef str);
+  explicit Oid(std::string_view str);
 
   // Since Oid would not be constructed by itself, the destructor is not
   // responsible for freeing the raw pointer.
diff --git a/src/Git2/Repository.cc b/src/Git2/Repository.cc
index 8f0982553..1e74b0027 100644
--- a/src/Git2/Repository.cc
+++ b/src/Git2/Repository.cc
@@ -1,6 +1,5 @@
 #include "Repository.hpp"
 
-#include "../Rustify.hpp"
 #include "Config.hpp"
 #include "Exception.hpp"
 #include "Oid.hpp"
@@ -8,6 +7,7 @@
 #include <git2/ignore.h>
 #include <git2/repository.h>
 #include <git2/revparse.h>
+#include <string_view>
 
 namespace git2 {
 
@@ -16,29 +16,29 @@ Repository::~Repository() {
 }
 
 Repository&
-Repository::open(const StringRef path) {
+Repository::open(const std::string_view path) {
   git2Throw(git_repository_open(&this->raw, path.data()));
   return *this;
 }
 Repository&
-Repository::openBare(const StringRef path) {
+Repository::openBare(const std::string_view path) {
   git2Throw(git_repository_open_bare(&this->raw, path.data()));
   return *this;
 }
 
 Repository&
-Repository::init(const StringRef path) {
+Repository::init(const std::string_view path) {
   git2Throw(git_repository_init(&this->raw, path.data(), false));
   return *this;
 }
 Repository&
-Repository::initBare(const StringRef path) {
+Repository::initBare(const std::string_view path) {
   git2Throw(git_repository_init(&this->raw, path.data(), true));
   return *this;
 }
 
 bool
-Repository::isIgnored(const StringRef path) const {
+Repository::isIgnored(const std::string_view path) const {
   int ignored = 0;
   git2Throw(git_ignore_path_is_ignored(&ignored, this->raw, path.data()));
   return static_cast<bool>(ignored);
@@ -46,14 +46,15 @@ Repository::isIgnored(const StringRef path) const {
 
 Repository&
 Repository::clone(
-    const StringRef url, const StringRef path, const git_clone_options* opts
+    const std::string_view url, const std::string_view path,
+    const git_clone_options* opts
 ) {
   git2Throw(git_clone(&this->raw, url.data(), path.data(), opts));
   return *this;
 }
 
 Object
-Repository::revparseSingle(const StringRef spec) const {
+Repository::revparseSingle(const std::string_view spec) const {
   git_object* obj = nullptr;
   git2Throw(git_revparse_single(&obj, this->raw, spec.data()));
   return git2::Object(obj);
@@ -75,7 +76,7 @@ Repository::checkoutHead(bool force) {
 }
 
 Oid
-Repository::refNameToId(const StringRef refname) const {
+Repository::refNameToId(const std::string_view refname) const {
   git_oid oid;
   git2Throw(git_reference_name_to_id(&oid, this->raw, refname.data()));
   return Oid(oid);
diff --git a/src/Git2/Repository.hpp b/src/Git2/Repository.hpp
index 4c937c458..c32f95af6 100644
--- a/src/Git2/Repository.hpp
+++ b/src/Git2/Repository.hpp
@@ -1,6 +1,5 @@
 #pragma once
 
-#include "../Rustify.hpp"
 #include "Config.hpp"
 #include "Global.hpp"
 #include "Object.hpp"
@@ -8,6 +7,7 @@
 
 #include <git2/clone.h>
 #include <git2/repository.h>
+#include <string_view>
 
 namespace git2 {
 
@@ -25,32 +25,34 @@ struct Repository : public GlobalState {
   /// Attempt to open an already-existing repository at `path`.
   ///
   /// The path can point to either a normal or bare repository.
-  Repository& open(StringRef path);
+  Repository& open(std::string_view path);
   /// Attempt to open an already-existing bare repository at `path`.
   ///
   /// The path can point to only a bare repository.
-  Repository& openBare(StringRef path);
+  Repository& openBare(std::string_view path);
 
   /// Creates a new repository in the specified folder.
   ///
   /// This by default will create any necessary directories to create the
   /// repository, and it will read any user-specified templates when creating
   /// the repository. This behavior can be configured through `init_opts`.
-  Repository& init(StringRef path);
+  Repository& init(std::string_view path);
   /// Creates a new `--bare` repository in the specified folder.
   ///
   /// The folder must exist prior to invoking this function.
-  Repository& initBare(StringRef path);
+  Repository& initBare(std::string_view path);
 
   /// Check if path is ignored by the ignore rules.
-  bool isIgnored(StringRef path) const;
+  bool isIgnored(std::string_view path) const;
 
   /// Clone a remote repository.
-  Repository&
-  clone(StringRef url, StringRef path, const git_clone_options* opts = nullptr);
+  Repository& clone(
+      std::string_view url, std::string_view path,
+      const git_clone_options* opts = nullptr
+  );
 
   /// Find a single object, as specified by a revision string.
-  Object revparseSingle(StringRef spec) const;
+  Object revparseSingle(std::string_view spec) const;
 
   /// Make the repository HEAD directly point to the Commit.
   Repository& setHeadDetached(const Oid& oid);
@@ -59,7 +61,7 @@ struct Repository : public GlobalState {
   Repository& checkoutHead(bool force = false);
 
   /// Lookup a reference by name and resolve immediately to OID.
-  Oid refNameToId(StringRef refname) const;
+  Oid refNameToId(std::string_view refname) const;
 
   /// Get the configuration file for this repository.
   ///
diff --git a/src/Git2/Revwalk.cc b/src/Git2/Revwalk.cc
index 12ab6713b..10019db30 100644
--- a/src/Git2/Revwalk.cc
+++ b/src/Git2/Revwalk.cc
@@ -1,10 +1,10 @@
 #include "Revwalk.hpp"
 
-#include "../Rustify.hpp"
 #include "Exception.hpp"
 #include "Repository.hpp"
 
 #include <git2/revwalk.h>
+#include <string_view>
 
 namespace git2 {
 
@@ -46,19 +46,19 @@ Revwalk::pushHead() {
 }
 
 Revwalk&
-Revwalk::pushGlob(const StringRef glob) {
+Revwalk::pushGlob(const std::string_view glob) {
   git2Throw(git_revwalk_push_glob(this->raw, glob.data()));
   return *this;
 }
 
 Revwalk&
-Revwalk::pushRange(const StringRef range) {
+Revwalk::pushRange(const std::string_view range) {
   git2Throw(git_revwalk_push_range(this->raw, range.data()));
   return *this;
 }
 
 Revwalk&
-Revwalk::pushRef(const StringRef reference) {
+Revwalk::pushRef(const std::string_view reference) {
   git2Throw(git_revwalk_push_ref(this->raw, reference.data()));
   return *this;
 }
@@ -76,13 +76,13 @@ Revwalk::hideHead() {
 }
 
 Revwalk&
-Revwalk::hideGlob(const StringRef glob) {
+Revwalk::hideGlob(const std::string_view glob) {
   git2Throw(git_revwalk_hide_glob(this->raw, glob.data()));
   return *this;
 }
 
 Revwalk&
-Revwalk::hideRef(const StringRef reference) {
+Revwalk::hideRef(const std::string_view reference) {
   git2Throw(git_revwalk_hide_ref(this->raw, reference.data()));
   return *this;
 }
diff --git a/src/Git2/Revwalk.hpp b/src/Git2/Revwalk.hpp
index ebf01e517..585274711 100644
--- a/src/Git2/Revwalk.hpp
+++ b/src/Git2/Revwalk.hpp
@@ -1,11 +1,11 @@
 #pragma once
 
-#include "../Rustify.hpp"
 #include "Global.hpp"
 #include "Oid.hpp"
 #include "Repository.hpp"
 
 #include <git2/revwalk.h>
+#include <string_view>
 
 namespace git2 {
 
@@ -59,19 +59,19 @@ struct Revwalk : public GlobalState {
   ///
   /// Any references matching this glob which do not point to a committish
   /// will be ignored.
-  Revwalk& pushGlob(StringRef glob);
+  Revwalk& pushGlob(std::string_view glob);
 
   /// Push and hide the respective endpoints of the given range.
   ///
   /// The range should be of the form `<commit>..<commit>` where each
   /// `<commit>` is in the form accepted by `revparse_single`. The left-hand
   /// commit will be hidden and the right-hand commit pushed.
-  Revwalk& pushRange(StringRef range);
+  Revwalk& pushRange(std::string_view range);
 
   /// Push the OID pointed to by a reference
   ///
   /// The reference must point to a committish.
-  Revwalk& pushRef(StringRef reference);
+  Revwalk& pushRef(std::string_view reference);
 
   /// Mark a commit as not of interest to this revwalk.
   Revwalk& hide(const Oid& oid);
@@ -91,12 +91,12 @@ struct Revwalk : public GlobalState {
   ///
   /// Any references matching this glob which do not point to a committish
   /// will be ignored.
-  Revwalk& hideGlob(StringRef glob);
+  Revwalk& hideGlob(std::string_view glob);
 
   /// Hide the OID pointed to by a reference.
   ///
   /// The reference must point to a committish.
-  Revwalk& hideRef(StringRef reference);
+  Revwalk& hideRef(std::string_view reference);
 };
 
 } // end namespace git2
diff --git a/src/Logger.hpp b/src/Logger.hpp
index cd6c7fa17..0c16c6a4b 100644
--- a/src/Logger.hpp
+++ b/src/Logger.hpp
@@ -8,6 +8,7 @@
 #include <iomanip>
 #include <iostream>
 #include <ostream>
+#include <string_view>
 #include <type_traits>
 #include <utility>
 
@@ -26,8 +27,8 @@ template <typename T>
 concept MaybeWriter = Writer<T> || Display<T>;
 
 template <typename Fn>
-concept HeadProcessor = std::is_nothrow_invocable_v<Fn, StringRef>
-                        && Display<std::invoke_result_t<Fn, StringRef>>;
+concept HeadProcessor = std::is_nothrow_invocable_v<Fn, std::string_view>
+                        && Display<std::invoke_result_t<Fn, std::string_view>>;
 
 class Logger {
   Level level = Level::Info;
@@ -56,22 +57,22 @@ class Logger {
   static void error(MaybeWriter auto&&... msgs) noexcept {
     logln(
         Level::Error,
-        [](const StringRef head) noexcept { return bold(red(head)); },
+        [](const std::string_view head) noexcept { return bold(red(head)); },
         "Error: ", std::forward<decltype(msgs)>(msgs)...
     );
   }
   static void warn(MaybeWriter auto&&... msgs) noexcept {
     logln(
         Level::Warn,
-        [](const StringRef head) noexcept { return bold(yellow(head)); },
+        [](const std::string_view head) noexcept { return bold(yellow(head)); },
         "Warning: ", std::forward<decltype(msgs)>(msgs)...
     );
   }
   static void info(MaybeWriter auto&&... msgs) noexcept {
     logln(
         Level::Info,
-        [](const StringRef head) noexcept {
-          const StringRef fmtStr = shouldColor() ? "{:>21} " : "{:>12} ";
+        [](const std::string_view head) noexcept {
+          const std::string_view fmtStr = shouldColor() ? "{:>21} " : "{:>12} ";
           return fmt::format(fmt::runtime(fmtStr), bold(green(head)));
         },
         std::forward<decltype(msgs)>(msgs)...
@@ -90,7 +91,7 @@ class Logger {
 
 private:
   static void debuglike(
-      Level level, const StringRef lvlStr, const StringRef func,
+      Level level, const std::string_view lvlStr, const std::string_view func,
       Writer auto&& writer, Display auto&&... msgs
   ) noexcept {
     // Swap func and writer, since for logln, writer should appear first for
@@ -101,12 +102,12 @@ class Logger {
     );
   }
   static void debuglike(
-      Level level, const StringRef lvlStr, MaybeWriter auto&& maybeWriter,
-      Display auto&&... msgs
+      Level level, const std::string_view lvlStr,
+      MaybeWriter auto&& maybeWriter, Display auto&&... msgs
   ) noexcept {
     logln(
         level,
-        [lvlStr](const StringRef func) noexcept {
+        [lvlStr](const std::string_view func) noexcept {
           return fmt::format(
               "{}Poac {} {}{} ", gray("["), lvlStr, func, gray("]")
           );
diff --git a/src/Manifest.cc b/src/Manifest.cc
index c65df83f7..122ec4534 100644
--- a/src/Manifest.cc
+++ b/src/Manifest.cc
@@ -12,6 +12,7 @@
 #include <cctype>
 #include <cstdlib>
 #include <string>
+#include <string_view>
 #include <variant>
 
 #define TOML11_NO_ERROR_PREFIX
@@ -190,7 +191,7 @@ getManifestPath() {
 
 // Returns an error message if the package name is invalid.
 Option<std::string> // TODO: result-like types make more sense.
-validatePackageName(const StringRef name) noexcept {
+validatePackageName(const std::string_view name) noexcept {
   // Empty
   if (name.empty()) {
     return "must not be empty";
@@ -220,7 +221,7 @@ validatePackageName(const StringRef name) noexcept {
   }
 
   // Using C++ keywords
-  const HashSet<StringRef> keywords = {
+  const HashSet<std::string_view> keywords = {
 #include "Keywords.def"
   };
   if (keywords.contains(name)) {
@@ -264,7 +265,7 @@ getPackageVersion() {
 }
 
 static void
-validateCxxflag(const StringRef cxxflag) {
+validateCxxflag(const std::string_view cxxflag) {
   // cxxflag must start with `-`
   if (cxxflag.empty() || cxxflag[0] != '-') {
     throw PoacError("cxxflag must start with `-`");
@@ -406,7 +407,7 @@ static const HashSet<char> ALLOWED_CHARS = {
 };
 
 static void
-validateDepName(const StringRef name) {
+validateDepName(const std::string_view name) {
   if (name.empty()) {
     throw PoacError("dependency name is empty");
   }
diff --git a/src/Manifest.hpp b/src/Manifest.hpp
index 0520541aa..aad4517bf 100644
--- a/src/Manifest.hpp
+++ b/src/Manifest.hpp
@@ -5,6 +5,7 @@
 
 #include <compare>
 #include <string>
+#include <string_view>
 
 struct DepMetadata {
   std::string includes; // -Isomething
@@ -53,7 +54,7 @@ struct Edition {
 };
 
 const fs::path& getManifestPath();
-Option<std::string> validatePackageName(StringRef name) noexcept;
+Option<std::string> validatePackageName(std::string_view name) noexcept;
 const std::string& getPackageName();
 const Edition& getPackageEdition();
 const Version& getPackageVersion();
diff --git a/src/Rustify/Aliases.hpp b/src/Rustify/Aliases.hpp
index 5848af661..f51df2127 100644
--- a/src/Rustify/Aliases.hpp
+++ b/src/Rustify/Aliases.hpp
@@ -33,8 +33,6 @@ using f32 = float;
 using f64 = double;
 // NOLINTEND(readability-identifier-naming)
 
-using StringRef = std::string_view;
-
 template <typename T, usize N>
 using Arr = std::array<T, N>;
 template <typename T>
@@ -102,13 +100,13 @@ struct source_location {
   ) noexcept {
     return { file, line, func };
   }
-  constexpr StringRef file_name() const noexcept {
+  constexpr std::string_view file_name() const noexcept {
     return file_;
   }
   constexpr int line() const noexcept {
     return line_;
   }
-  constexpr StringRef function_name() const noexcept {
+  constexpr std::string_view function_name() const noexcept {
     return func_;
   }
 
@@ -121,7 +119,8 @@ struct source_location {
 
 [[noreturn]] inline void
 panic(
-    const StringRef msg, const source_location& loc = source_location::current()
+    const std::string_view msg,
+    const source_location& loc = source_location::current()
 ) noexcept {
   std::cerr << "panicked at '" << msg << "', " << loc.file_name() << ':'
             << loc.line() << '\n';
diff --git a/src/Rustify/Tests.hpp b/src/Rustify/Tests.hpp
index ee240cd7f..c47750d1c 100644
--- a/src/Rustify/Tests.hpp
+++ b/src/Rustify/Tests.hpp
@@ -7,15 +7,16 @@
 #include <exception>
 #include <iostream>
 #include <string>
+#include <string_view>
 #include <type_traits>
 #include <typeinfo>
 #include <utility>
 
 namespace tests {
 
-inline constinit const StringRef GREEN = "\033[32m";
-inline constinit const StringRef RED = "\033[31m";
-inline constinit const StringRef RESET = "\033[0m";
+inline constinit const std::string_view GREEN = "\033[32m";
+inline constinit const std::string_view RED = "\033[31m";
+inline constinit const std::string_view RESET = "\033[0m";
 
 inline constinit const usize SRC_REL_PATH_LEN = 6; // `../../`
 
@@ -29,8 +30,8 @@ inline constinit const usize SRC_REL_PATH_LEN = 6; // `../../`
 // We first should remove `../../` if it exists, then remove the first
 // directory name since it can be either `src` or `tests`.  Finally, we remove
 // the file extension, which is basically any of C++ source file extensions.
-inline constexpr StringRef
-modName(StringRef file) noexcept {
+inline constexpr std::string_view
+modName(std::string_view file) noexcept {
   if (file.empty()) {
     return file;
   }
@@ -40,13 +41,13 @@ modName(StringRef file) noexcept {
   }
 
   usize start = file.find_first_of('/');
-  if (start == StringRef::npos) {
+  if (start == std::string_view::npos) {
     return file;
   }
   ++start;
 
   const usize end = file.find_last_of('.');
-  if (end == StringRef::npos) {
+  if (end == std::string_view::npos) {
     return file;
   }
 
@@ -74,7 +75,7 @@ error(const source_location& loc, Display auto&&... msgs) noexcept {
 
 inline void
 assertTrue(
-    const bool cond, const StringRef msg = "",
+    const bool cond, const std::string_view msg = "",
     const source_location& loc = source_location::current()
 ) noexcept {
   if (cond) {
@@ -90,7 +91,7 @@ assertTrue(
 
 inline void
 assertFalse(
-    const bool cond, const StringRef msg = "",
+    const bool cond, const std::string_view msg = "",
     const source_location& loc = source_location::current()
 ) noexcept {
   if (!cond) {
@@ -108,7 +109,7 @@ template <typename Lhs, typename Rhs>
   requires(Eq<Lhs, Rhs> && Display<Lhs> && Display<Rhs>)
 inline void
 assertEq(
-    Lhs&& lhs, Rhs&& rhs, const StringRef msg = "",
+    Lhs&& lhs, Rhs&& rhs, const std::string_view msg = "",
     const source_location& loc = source_location::current()
 ) noexcept {
   if (lhs == rhs) {
@@ -130,7 +131,7 @@ template <typename Lhs, typename Rhs>
   requires(Ne<Lhs, Rhs> && Display<Lhs> && Display<Rhs>)
 inline void
 assertNe(
-    Lhs&& lhs, Rhs&& rhs, const StringRef msg = "",
+    Lhs&& lhs, Rhs&& rhs, const std::string_view msg = "",
     const source_location& loc = source_location::current()
 ) noexcept {
   if (lhs != rhs) {
@@ -152,7 +153,7 @@ template <typename Lhs, typename Rhs>
   requires(Lt<Lhs, Rhs> && Display<Lhs> && Display<Rhs>)
 inline void
 assertLt(
-    Lhs&& lhs, Rhs&& rhs, const StringRef msg = "",
+    Lhs&& lhs, Rhs&& rhs, const std::string_view msg = "",
     const source_location& loc = source_location::current()
 ) noexcept {
   if (lhs < rhs) {
@@ -174,7 +175,7 @@ template <typename E, typename Fn>
   requires(std::is_invocable_v<Fn>)
 inline void
 assertException(
-    Fn&& func, const StringRef msg,
+    Fn&& func, const std::string_view msg,
     const source_location& loc = source_location::current()
 ) noexcept {
   try {
diff --git a/src/Semver.cc b/src/Semver.cc
index 7ac2cdcde..2766ac6fe 100644
--- a/src/Semver.cc
+++ b/src/Semver.cc
@@ -7,6 +7,7 @@
 #include <ostream>
 #include <sstream>
 #include <string>
+#include <string_view>
 
 std::ostream&
 operator<<(std::ostream& os, const VersionToken& tok) noexcept {
@@ -15,7 +16,7 @@ operator<<(std::ostream& os, const VersionToken& tok) noexcept {
       os << std::get<u64>(tok.value);
       break;
     case VersionToken::Ident:
-      os << std::get<StringRef>(tok.value);
+      os << std::get<std::string_view>(tok.value);
       break;
     case VersionToken::Dot:
       os << '.';
@@ -54,7 +55,8 @@ operator==(const VersionToken& lhs, const VersionToken& rhs) noexcept {
     case VersionToken::Num:
       return std::get<u64>(lhs.value) == std::get<u64>(rhs.value);
     case VersionToken::Ident:
-      return std::get<StringRef>(lhs.value) == std::get<StringRef>(rhs.value);
+      return std::get<std::string_view>(lhs.value)
+             == std::get<std::string_view>(rhs.value);
     case VersionToken::Dot:
     case VersionToken::Hyphen:
     case VersionToken::Plus:
@@ -267,7 +269,7 @@ VersionLexer::consumeIdent() noexcept {
     step();
     ++len;
   }
-  return { VersionToken::Ident, StringRef(s.data() + pos - len, len) };
+  return { VersionToken::Ident, std::string_view(s.data() + pos - len, len) };
 }
 
 VersionToken
@@ -354,7 +356,8 @@ VersionLexer::peek() {
 
 struct SemverParseError : public SemverError {
   SemverParseError(
-      const VersionLexer& lexer, const VersionToken& tok, const StringRef msg
+      const VersionLexer& lexer, const VersionToken& tok,
+      const std::string_view msg
   )
       : SemverError(
             lexer.s, '\n', std::string(lexer.pos, ' '), carets(tok), msg
@@ -461,19 +464,19 @@ VersionParser::parseIdent() {
 }
 
 Prerelease
-Prerelease::parse(const StringRef str) {
+Prerelease::parse(const std::string_view str) {
   VersionParser parser(str);
   return parser.parsePre();
 }
 
 BuildMetadata
-BuildMetadata::parse(const StringRef str) {
+BuildMetadata::parse(const std::string_view str) {
   VersionParser parser(str);
   return parser.parseBuild();
 }
 
 Version
-Version::parse(const StringRef str) {
+Version::parse(const std::string_view str) {
   VersionParser parser(str);
   return parser.parse();
 }
diff --git a/src/Semver.hpp b/src/Semver.hpp
index 6e57799e0..1a2399c99 100644
--- a/src/Semver.hpp
+++ b/src/Semver.hpp
@@ -14,6 +14,7 @@
 
 #include <ostream>
 #include <string>
+#include <string_view>
 #include <utility>
 #include <variant>
 
@@ -35,10 +36,11 @@ struct VersionToken {
   using enum Kind;
 
   Kind kind;
-  std::variant<std::monostate, u64, StringRef> value;
+  std::variant<std::monostate, u64, std::string_view> value;
 
   constexpr VersionToken(
-      Kind kind, const std::variant<std::monostate, u64, StringRef>& value
+      Kind kind,
+      const std::variant<std::monostate, u64, std::string_view>& value
   ) noexcept
       : kind(kind), value(value) {}
   constexpr explicit VersionToken(Kind kind) noexcept
@@ -51,7 +53,7 @@ struct VersionToken {
 struct Prerelease {
   Vec<VersionToken> ident;
 
-  static Prerelease parse(StringRef str);
+  static Prerelease parse(std::string_view str);
   bool empty() const noexcept;
   std::string toString() const noexcept;
 };
@@ -65,7 +67,7 @@ bool operator>=(const Prerelease& lhs, const Prerelease& rhs) noexcept;
 struct BuildMetadata {
   Vec<VersionToken> ident;
 
-  static BuildMetadata parse(StringRef str);
+  static BuildMetadata parse(std::string_view str);
   bool empty() const noexcept;
   std::string toString() const noexcept;
 };
@@ -77,7 +79,7 @@ struct Version {
   Prerelease pre;
   BuildMetadata build;
 
-  static Version parse(StringRef str);
+  static Version parse(std::string_view str);
   std::string toString() const noexcept;
 };
 std::ostream& operator<<(std::ostream& os, const Version& ver) noexcept;
@@ -89,10 +91,11 @@ bool operator<=(const Version& lhs, const Version& rhs) noexcept;
 bool operator>=(const Version& lhs, const Version& rhs) noexcept;
 
 struct VersionLexer {
-  StringRef s;
+  std::string_view s;
   usize pos{ 0 };
 
-  constexpr explicit VersionLexer(const StringRef str) noexcept : s(str) {}
+  constexpr explicit VersionLexer(const std::string_view str) noexcept
+      : s(str) {}
 
   constexpr bool isEof() const noexcept {
     return pos >= s.size();
@@ -110,7 +113,8 @@ struct VersionLexer {
 struct VersionParser {
   VersionLexer lexer;
 
-  constexpr explicit VersionParser(const StringRef str) noexcept : lexer(str) {}
+  constexpr explicit VersionParser(const std::string_view str) noexcept
+      : lexer(str) {}
 
   Version parse();
   u64 parseNum();
diff --git a/src/TermColor.cc b/src/TermColor.cc
index 89180e55e..bba8a0fc1 100644
--- a/src/TermColor.cc
+++ b/src/TermColor.cc
@@ -5,6 +5,7 @@
 
 #include <cstdlib>
 #include <string>
+#include <string_view>
 
 static bool
 isTerm() noexcept {
@@ -12,7 +13,7 @@ isTerm() noexcept {
 }
 
 static ColorMode
-getColorMode(const StringRef str) noexcept {
+getColorMode(const std::string_view str) noexcept {
   if (str == "always") {
     return ColorMode::Always;
   } else if (str == "auto") {
@@ -74,7 +75,7 @@ setColorMode(const ColorMode mode) noexcept {
 }
 
 void
-setColorMode(const StringRef str) noexcept {
+setColorMode(const std::string_view str) noexcept {
   setColorMode(getColorMode(str));
 }
 
@@ -84,7 +85,7 @@ shouldColor() noexcept {
 }
 
 static std::string
-colorize(const StringRef str, const StringRef code) noexcept {
+colorize(const std::string_view str, const std::string_view code) noexcept {
   if (!shouldColor()) {
     return std::string(str);
   }
@@ -115,35 +116,35 @@ colorize(const StringRef str, const StringRef code) noexcept {
 }
 
 std::string
-gray(const StringRef str) noexcept {
+gray(const std::string_view str) noexcept {
   return colorize(str, "30");
 }
 std::string
-red(const StringRef str) noexcept {
+red(const std::string_view str) noexcept {
   return colorize(str, "31");
 }
 std::string
-green(const StringRef str) noexcept {
+green(const std::string_view str) noexcept {
   return colorize(str, "32");
 }
 std::string
-yellow(const StringRef str) noexcept {
+yellow(const std::string_view str) noexcept {
   return colorize(str, "33");
 }
 std::string
-blue(const StringRef str) noexcept {
+blue(const std::string_view str) noexcept {
   return colorize(str, "34");
 }
 std::string
-magenta(const StringRef str) noexcept {
+magenta(const std::string_view str) noexcept {
   return colorize(str, "35");
 }
 std::string
-cyan(const StringRef str) noexcept {
+cyan(const std::string_view str) noexcept {
   return colorize(str, "36");
 }
 
 std::string
-bold(const StringRef str) noexcept {
+bold(const std::string_view str) noexcept {
   return colorize(str, "1");
 }
diff --git a/src/TermColor.hpp b/src/TermColor.hpp
index cbeacce12..83bc80ffe 100644
--- a/src/TermColor.hpp
+++ b/src/TermColor.hpp
@@ -1,8 +1,7 @@
 #pragma once
 
-#include "Rustify.hpp"
-
 #include <string>
+#include <string_view>
 
 enum class ColorMode {
   Always,
@@ -11,15 +10,15 @@ enum class ColorMode {
 };
 
 void setColorMode(ColorMode mode) noexcept;
-void setColorMode(StringRef str) noexcept;
+void setColorMode(std::string_view str) noexcept;
 bool shouldColor() noexcept;
 
-std::string gray(StringRef str) noexcept;
-std::string red(StringRef str) noexcept;
-std::string green(StringRef str) noexcept;
-std::string yellow(StringRef str) noexcept;
-std::string blue(StringRef str) noexcept;
-std::string magenta(StringRef str) noexcept;
-std::string cyan(StringRef str) noexcept;
+std::string gray(std::string_view str) noexcept;
+std::string red(std::string_view str) noexcept;
+std::string green(std::string_view str) noexcept;
+std::string yellow(std::string_view str) noexcept;
+std::string blue(std::string_view str) noexcept;
+std::string magenta(std::string_view str) noexcept;
+std::string cyan(std::string_view str) noexcept;
 
-std::string bold(StringRef str) noexcept;
+std::string bold(std::string_view str) noexcept;
diff --git a/src/VersionReq.cc b/src/VersionReq.cc
index 88ea6f134..1fcaf47ab 100644
--- a/src/VersionReq.cc
+++ b/src/VersionReq.cc
@@ -6,6 +6,7 @@
 #include <cctype>
 #include <iostream>
 #include <string>
+#include <string_view>
 #include <utility>
 #include <variant>
 
@@ -67,10 +68,10 @@ struct ComparatorToken {
 };
 
 struct ComparatorLexer {
-  StringRef s;
+  std::string_view s;
   usize pos{ 0 };
 
-  explicit ComparatorLexer(const StringRef str) noexcept : s(str) {}
+  explicit ComparatorLexer(const std::string_view str) noexcept : s(str) {}
 
   bool isEof() const noexcept {
     return pos >= s.size();
@@ -157,7 +158,7 @@ struct ComparatorLexer {
 struct ComparatorParser {
   ComparatorLexer lexer;
 
-  explicit ComparatorParser(const StringRef str) noexcept : lexer(str) {}
+  explicit ComparatorParser(const std::string_view str) noexcept : lexer(str) {}
 
   Comparator parse() {
     Comparator result;
@@ -207,7 +208,7 @@ struct ComparatorParser {
 };
 
 Comparator
-Comparator::parse(const StringRef str) {
+Comparator::parse(const std::string_view str) {
   ComparatorParser parser(str);
   return parser.parse();
 }
@@ -462,10 +463,10 @@ isCompStart(const char c) noexcept {
 }
 
 struct VersionReqLexer {
-  StringRef s;
+  std::string_view s;
   usize pos{ 0 };
 
-  explicit VersionReqLexer(const StringRef str) noexcept : s(str) {}
+  explicit VersionReqLexer(const std::string_view str) noexcept : s(str) {}
 
   bool isEof() const noexcept {
     return pos >= s.size();
@@ -504,7 +505,7 @@ struct VersionReqLexer {
 struct VersionReqParser {
   VersionReqLexer lexer;
 
-  explicit VersionReqParser(const StringRef str) noexcept : lexer(str) {}
+  explicit VersionReqParser(const std::string_view str) noexcept : lexer(str) {}
 
   VersionReq parse() {
     VersionReq result;
@@ -589,7 +590,7 @@ struct VersionReqParser {
 };
 
 VersionReq
-VersionReq::parse(const StringRef str) {
+VersionReq::parse(const std::string_view str) {
   VersionReqParser parser(str);
   return parser.parse();
 }
@@ -823,7 +824,7 @@ VersionReq::toString() const noexcept {
 }
 
 std::string
-VersionReq::toPkgConfigString(const StringRef name) const noexcept {
+VersionReq::toPkgConfigString(const std::string_view name) const noexcept {
   // For pkg-config, canonicalization is necessary.
   const VersionReq req = canonicalize();
 
@@ -903,20 +904,20 @@ namespace tests {
 
 inline void
 assertMatchAll(
-    const VersionReq& req, const std::span<const StringRef> versions,
+    const VersionReq& req, const std::span<const std::string_view> versions,
     const source_location& loc = source_location::current()
 ) {
-  for (const StringRef ver : versions) {
+  for (const std::string_view ver : versions) {
     assertTrue(req.satisfiedBy(Version::parse(ver)), "", loc);
   }
 }
 
 inline void
 assertMatchNone(
-    const VersionReq& req, const std::span<const StringRef> versions,
+    const VersionReq& req, const std::span<const std::string_view> versions,
     const source_location& loc = source_location::current()
 ) {
-  for (const StringRef ver : versions) {
+  for (const std::string_view ver : versions) {
     assertFalse(req.satisfiedBy(Version::parse(ver)), "", loc);
   }
 }
diff --git a/src/VersionReq.hpp b/src/VersionReq.hpp
index f18d42f1b..6e2d61291 100644
--- a/src/VersionReq.hpp
+++ b/src/VersionReq.hpp
@@ -19,6 +19,7 @@
 
 #include <ostream>
 #include <string>
+#include <string_view>
 
 struct OptVersion {
   u64 major{};
@@ -75,7 +76,7 @@ struct Comparator {
   Option<u64> patch;
   Prerelease pre;
 
-  static Comparator parse(StringRef str);
+  static Comparator parse(std::string_view str);
   void from(const OptVersion& ver) noexcept;
   std::string toString() const noexcept;
   std::string toPkgConfigString() const noexcept;
@@ -87,10 +88,10 @@ struct VersionReq {
   Comparator left;
   Option<Comparator> right;
 
-  static VersionReq parse(StringRef str);
+  static VersionReq parse(std::string_view str);
   bool satisfiedBy(const Version& ver) const noexcept;
   std::string toString() const noexcept;
-  std::string toPkgConfigString(StringRef name) const noexcept;
+  std::string toPkgConfigString(std::string_view name) const noexcept;
   VersionReq canonicalize() const noexcept;
   bool canSimplify() const noexcept;
 };
diff --git a/src/main.cc b/src/main.cc
index aa722a559..776ba8909 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -7,6 +7,7 @@
 #include <cstdlib>
 #include <exception>
 #include <span>
+#include <string_view>
 
 const Cli&
 getCli() noexcept {
@@ -76,7 +77,7 @@ main(int argc, char* argv[]) {
 
     // Local options
     else if (*itr == "-V"sv || *itr == "--version"sv) {
-      const Vec<StringRef> remArgs(itr + 1, args.end());
+      const Vec<std::string_view> remArgs(itr + 1, args.end());
       return versionMain(remArgs);
     } else if (*itr == "--list"sv) {
       getCli().printAllSubcmds(true);
@@ -86,7 +87,7 @@ main(int argc, char* argv[]) {
     // Subcommands
     else if (getCli().hasSubcmd(*itr)) {
       try {
-        const Vec<StringRef> remArgs(itr + 1, args.end());
+        const Vec<std::string_view> remArgs(itr + 1, args.end());
         const int exitCode = getCli().exec(*itr, remArgs);
         if (exitCode != EXIT_SUCCESS) {
           logger::error(
diff --git a/srcOld/Cfg.hpp b/srcOld/Cfg.hpp
index dda14f8cf..d7b7ab228 100644
--- a/srcOld/Cfg.hpp
+++ b/srcOld/Cfg.hpp
@@ -5,6 +5,7 @@ module;
 #include <memory>
 #include <stdexcept>
 #include <string>
+#include <string_view>
 #include <utility>
 #include <variant>
 
@@ -147,7 +148,7 @@ struct Token {
   };
 
   Kind kind;
-  using StringType = StringRef;
+  using StringType = std::string_view;
   std::variant<std::monostate, StringType, ident> value;
 
   explicit Token(Kind k)
@@ -189,7 +190,7 @@ struct Token {
 };
 
 constexpr auto
-to_kind(StringRef kind) -> Token::Kind {
+to_kind(std::string_view kind) -> Token::Kind {
   if (kind == "(") {
     return Token::LeftParen;
   } else if (kind == ")") {
@@ -268,13 +269,13 @@ operator<<(std::ostream& os, const Token& token) -> std::ostream& {
 }
 
 struct Lexer {
-  using ValueType = StringRef::value_type;
+  using ValueType = std::string_view::value_type;
   using SizeType = usize;
 
-  StringRef str;
+  std::string_view str;
   SizeType index{ 0 };
 
-  explicit Lexer(StringRef str) : str(str) {}
+  explicit Lexer(std::string_view str) : str(str) {}
 
   inline auto next() -> Option<Token> {
     const auto [diff, token] = tokenize(this->index);
@@ -294,8 +295,9 @@ struct Lexer {
   ) const -> std::pair<SizeType, Option<Token>> {
     return { this->diff_step(index_), token };
   }
-  [[nodiscard]] inline auto generate_token(SizeType index_, StringRef kind)
-      const -> std::pair<SizeType, Option<Token>> {
+  [[nodiscard]] inline auto generate_token(
+      SizeType index_, std::string_view kind
+  ) const -> std::pair<SizeType, Option<Token>> {
     return generate_token(index_, Token{ to_kind(kind) });
   }
 
@@ -323,7 +325,7 @@ struct Lexer {
 
   [[nodiscard]] auto ident(SizeType index_) const -> std::pair<SizeType, Token>;
 
-  static auto to_ident(StringRef s) noexcept -> Option<Token::ident>;
+  static auto to_ident(std::string_view s) noexcept -> Option<Token::ident>;
 };
 
 auto
@@ -397,7 +399,7 @@ Lexer::string(SizeType index_) const -> std::pair<Lexer::SizeType, Token> {
       throw cfg::StringError(std::string(this->str) + "\n" + msg);
     }
   }
-  const StringRef s = this->str.substr(start, index_ - start);
+  const std::string_view s = this->str.substr(start, index_ - start);
   this->step(index_);
   return { this->diff_step(index_), Token{ Token::std::string, s } };
 }
@@ -416,7 +418,7 @@ Lexer::ident(SizeType index_) const -> std::pair<Lexer::SizeType, Token> {
     this->step(index_);
   }
 
-  const StringRef s = this->str.substr(start, index_ - start);
+  const std::string_view s = this->str.substr(start, index_ - start);
   if (const auto ident = to_ident(s)) {
     return { this->diff_step(index_), Token{ Token::Ident, ident.value() } };
   } else {
@@ -430,7 +432,7 @@ Lexer::ident(SizeType index_) const -> std::pair<Lexer::SizeType, Token> {
 }
 
 auto
-Lexer::to_ident(StringRef s) noexcept -> Option<Token::ident> {
+Lexer::to_ident(std::string_view s) noexcept -> Option<Token::ident> {
   if (s == "cfg") {
     return Token::ident::cfg;
   } else if (s == "not") {
@@ -483,9 +485,9 @@ struct Cfg {
 
   Ident key;
   Op op;
-  StringRef value;
+  std::string_view value;
 
-  Cfg(Token::ident key, Op op, StringRef value)
+  Cfg(Token::ident key, Op op, std::string_view value)
       : key(from_token_ident(key)), op(op), value(value) {}
 
   Cfg() = delete;
@@ -700,7 +702,7 @@ CfgExpr::match(const Cfg& c) -> bool {
 struct Parser {
   Lexer lexer;
 
-  explicit Parser(StringRef str) : lexer(str) {}
+  explicit Parser(std::string_view str) : lexer(str) {}
 
   auto expr() -> CfgExpr;
 
@@ -872,7 +874,7 @@ Parser::eat_right_paren() {
 }
 
 inline auto
-parse(StringRef s) -> CfgExpr {
+parse(std::string_view s) -> CfgExpr {
   return Parser(s).expr();
 }
 
diff --git a/srcOld/Config.hpp b/srcOld/Config.hpp
index e283c9857..b6e525a72 100644
--- a/srcOld/Config.hpp
+++ b/srcOld/Config.hpp
@@ -40,7 +40,7 @@ inline const fs::path src_dir(cwd / "src");
 inline const fs::path include_dir(cwd / "include");
 inline const fs::path tests_dir(cwd / "tests");
 inline const fs::path main_cpp_file(src_dir / "main.cpp");
-inline constexpr StringRef POAC_OUT = "poac-out";
+inline constexpr std::string_view POAC_OUT = "poac-out";
 inline const fs::path out_dir(cwd / POAC_OUT);
 
 inline const fs::path conan_deps_dir(out_dir / ".conan");
diff --git a/srcOld/Lockfile.hpp b/srcOld/Lockfile.hpp
index bba888ed1..02eb72660 100644
--- a/srcOld/Lockfile.hpp
+++ b/srcOld/Lockfile.hpp
@@ -22,8 +22,8 @@ import poac.util.rustify;
 
 export namespace poac::data::lockfile {
 
-inline constexpr StringRef LOCKFILE_NAME = "poac.lock";
-inline constexpr StringRef LOCKFILE_HEADER =
+inline constexpr std::string_view LOCKFILE_NAME = "poac.lock";
+inline constexpr std::string_view LOCKFILE_HEADER =
     " This file is automatically generated by Poac.\n"
     "# It is not intended for manual editing.";
 
diff --git a/srcOld/Resolver.hpp b/srcOld/Resolver.hpp
index 26101116f..f255b4d8d 100644
--- a/srcOld/Resolver.hpp
+++ b/srcOld/Resolver.hpp
@@ -57,7 +57,7 @@ get_extracted_path(const resolve::Package& package) -> fs::path {
 /// Rename unknown extracted directory to easily access when building.
 [[nodiscard]] auto
 rename_extracted_directory(
-    const resolve::Package& package, StringRef extracted_directory_name
+    const resolve::Package& package, std::string_view extracted_directory_name
 ) -> Result<void> {
   const fs::path temporarily_extracted_path =
       config::default_registry_dir / extracted_directory_name;
@@ -78,7 +78,7 @@ get_archive_path(const resolve::Package& package) -> fs::path {
 }
 
 inline auto
-convert_to_download_link(StringRef repository) -> std::string {
+convert_to_download_link(std::string_view repository) -> std::string {
   // repository should be like =>
   //   https://github.com/boostorg/winapi/tree/boost-1.66.0
   // convert it to =>
@@ -98,10 +98,10 @@ convert_to_download_link(StringRef repository) -> std::string {
   // So, find the end of `tree/`.
   const usize end = repository.find('/', start);
   // Retrieve both sides: `https://github.com/tree/tree/`
-  const StringRef left = repository.substr(0, start);
+  const std::string_view left = repository.substr(0, start);
   // `/tree/v0.1.0`: this side is just a tag.
   // Mostly, we do not include `tree`, but we can.
-  StringRef right = repository.substr(end);
+  std::string_view right = repository.substr(end);
   return format("{}archive{}.tar.gz", left, right);
 }
 
diff --git a/srcOld/Resolver/Resolve.hpp b/srcOld/Resolver/Resolve.hpp
index 560a1cc28..4b3ec4c2a 100644
--- a/srcOld/Resolver/Resolve.hpp
+++ b/srcOld/Resolver/Resolve.hpp
@@ -214,7 +214,9 @@ get_versions_satisfy_interval(const Package& package
   const semver::Interval i(package.dep_info.version_rq);
   const Vec<std::string> satisfied_versions =
       Try(util::net::api::versions(package.name))
-      | boost::adaptors::filtered([&i](StringRef s) { return i.satisfies(s); })
+      | boost::adaptors::filtered([&i](std::string_view s) {
+          return i.satisfies(s);
+        })
       | util::meta::CONTAINERIZED;
 
   if (satisfied_versions.empty()) {