12 files changed, 70 insertions, 39 deletions

diff --git a/src/common/CMakeLists.txt b/src/common/CMakeLists.txt
index e50ab2922..207c7a0a6 100644
--- a/src/common/CMakeLists.txt
+++ b/src/common/CMakeLists.txt
@@ -190,6 +190,22 @@ if(ARCHITECTURE_x86_64)
     )
 endif()
 
+if (MSVC)
+  target_compile_definitions(common PRIVATE
+    # The standard library doesn't provide any replacement for codecvt yet
+    # so we can disable this deprecation warning for the time being.
+    _SILENCE_CXX17_CODECVT_HEADER_DEPRECATION_WARNING
+  )
+  target_compile_options(common PRIVATE
+    /W4
+    /WX
+  )
+else()
+  target_compile_options(common PRIVATE
+    -Werror
+  )
+endif()
+
 create_target_directory_groups(common)
 find_package(Boost 1.71 COMPONENTS context headers REQUIRED)
 
diff --git a/src/common/fiber.cpp b/src/common/fiber.cpp
index e186ed880..b209f52fc 100644
--- a/src/common/fiber.cpp
+++ b/src/common/fiber.cpp
@@ -79,9 +79,9 @@ void Fiber::Exit() {
     released = true;
 }
 
-void Fiber::SetRewindPoint(std::function<void(void*)>&& rewind_func, void* start_parameter) {
+void Fiber::SetRewindPoint(std::function<void(void*)>&& rewind_func, void* rewind_param) {
     rewind_point = std::move(rewind_func);
-    rewind_parameter = start_parameter;
+    rewind_parameter = rewind_param;
 }
 
 void Fiber::Rewind() {
@@ -161,9 +161,9 @@ Fiber::Fiber(std::function<void(void*)>&& entry_point_func, void* start_paramete
         boost::context::detail::make_fcontext(stack_base, impl->stack.size(), FiberStartFunc);
 }
 
-void Fiber::SetRewindPoint(std::function<void(void*)>&& rewind_func, void* start_parameter) {
+void Fiber::SetRewindPoint(std::function<void(void*)>&& rewind_func, void* rewind_param) {
     rewind_point = std::move(rewind_func);
-    rewind_parameter = start_parameter;
+    rewind_parameter = rewind_param;
 }
 
 Fiber::Fiber() : impl{std::make_unique<FiberImpl>()} {}
diff --git a/src/common/fiber.h b/src/common/fiber.h
index cefd61df9..699286ee2 100644
--- a/src/common/fiber.h
+++ b/src/common/fiber.h
@@ -49,7 +49,7 @@ public:
     static void YieldTo(std::shared_ptr<Fiber> from, std::shared_ptr<Fiber> to);
     [[nodiscard]] static std::shared_ptr<Fiber> ThreadToFiber();
 
-    void SetRewindPoint(std::function<void(void*)>&& rewind_func, void* start_parameter);
+    void SetRewindPoint(std::function<void(void*)>&& rewind_func, void* rewind_param);
 
     void Rewind();
 
diff --git a/src/common/file_util.cpp b/src/common/file_util.cpp
index 16c3713e0..18fbfa25b 100644
--- a/src/common/file_util.cpp
+++ b/src/common/file_util.cpp
@@ -472,13 +472,14 @@ u64 ScanDirectoryTree(const std::string& directory, FSTEntry& parent_entry,
 }
 
 bool DeleteDirRecursively(const std::string& directory, unsigned int recursion) {
-    const auto callback = [recursion](u64* num_entries_out, const std::string& directory,
-                                      const std::string& virtual_name) -> bool {
-        std::string new_path = directory + DIR_SEP_CHR + virtual_name;
+    const auto callback = [recursion](u64*, const std::string& directory,
+                                      const std::string& virtual_name) {
+        const std::string new_path = directory + DIR_SEP_CHR + virtual_name;
 
         if (IsDirectory(new_path)) {
-            if (recursion == 0)
+            if (recursion == 0) {
                 return false;
+            }
             return DeleteDirRecursively(new_path, recursion - 1);
         }
         return Delete(new_path);
@@ -492,7 +493,8 @@ bool DeleteDirRecursively(const std::string& directory, unsigned int recursion)
     return true;
 }
 
-void CopyDir(const std::string& source_path, const std::string& dest_path) {
+void CopyDir([[maybe_unused]] const std::string& source_path,
+             [[maybe_unused]] const std::string& dest_path) {
 #ifndef _WIN32
     if (source_path == dest_path) {
         return;
@@ -553,7 +555,7 @@ std::optional<std::string> GetCurrentDir() {
     std::string strDir = dir;
 #endif
     free(dir);
-    return std::move(strDir);
+    return strDir;
 }
 
 bool SetCurrentDir(const std::string& directory) {
@@ -772,21 +774,23 @@ std::size_t ReadFileToString(bool text_file, const std::string& filename, std::s
 
 void SplitFilename83(const std::string& filename, std::array<char, 9>& short_name,
                      std::array<char, 4>& extension) {
-    const std::string forbidden_characters = ".\"/\\[]:;=, ";
+    static constexpr std::string_view forbidden_characters = ".\"/\\[]:;=, ";
 
     // On a FAT32 partition, 8.3 names are stored as a 11 bytes array, filled with spaces.
     short_name = {{' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', '\0'}};
     extension = {{' ', ' ', ' ', '\0'}};
 
-    std::string::size_type point = filename.rfind('.');
-    if (point == filename.size() - 1)
+    auto point = filename.rfind('.');
+    if (point == filename.size() - 1) {
         point = filename.rfind('.', point);
+    }
 
     // Get short name.
     int j = 0;
     for (char letter : filename.substr(0, point)) {
-        if (forbidden_characters.find(letter, 0) != std::string::npos)
+        if (forbidden_characters.find(letter, 0) != std::string::npos) {
             continue;
+        }
         if (j == 8) {
             // TODO(Link Mauve): also do that for filenames containing a space.
             // TODO(Link Mauve): handle multiple files having the same short name.
@@ -794,14 +798,15 @@ void SplitFilename83(const std::string& filename, std::array<char, 9>& short_nam
             short_name[7] = '1';
             break;
         }
-        short_name[j++] = toupper(letter);
+        short_name[j++] = static_cast<char>(std::toupper(letter));
     }
 
     // Get extension.
     if (point != std::string::npos) {
         j = 0;
-        for (char letter : filename.substr(point + 1, 3))
-            extension[j++] = toupper(letter);
+        for (char letter : filename.substr(point + 1, 3)) {
+            extension[j++] = static_cast<char>(std::toupper(letter));
+        }
     }
 }
 
diff --git a/src/common/file_util.h b/src/common/file_util.h
index 8b587320f..840cde2a6 100644
--- a/src/common/file_util.h
+++ b/src/common/file_util.h
@@ -232,7 +232,7 @@ public:
 
     void Swap(IOFile& other) noexcept;
 
-    [[nodiscard]] bool Open(const std::string& filename, const char openmode[], int flags = 0);
+    bool Open(const std::string& filename, const char openmode[], int flags = 0);
     bool Close();
 
     template <typename T>
diff --git a/src/common/logging/backend.cpp b/src/common/logging/backend.cpp
index 62cfde397..90dfa22ca 100644
--- a/src/common/logging/backend.cpp
+++ b/src/common/logging/backend.cpp
@@ -274,7 +274,6 @@ const char* GetLogClassName(Class log_class) {
     case Class::Count:
         break;
     }
-    UNREACHABLE();
     return "Invalid";
 }
 
@@ -293,7 +292,6 @@ const char* GetLevelName(Level log_level) {
         break;
     }
 #undef LVL
-    UNREACHABLE();
     return "Invalid";
 }
 
diff --git a/src/common/misc.cpp b/src/common/misc.cpp
index 68cb86cd1..1d5393597 100644
--- a/src/common/misc.cpp
+++ b/src/common/misc.cpp
@@ -16,16 +16,23 @@
 // Call directly after the command or use the error num.
 // This function might change the error code.
 std::string GetLastErrorMsg() {
-    static const std::size_t buff_size = 255;
+    static constexpr std::size_t buff_size = 255;
     char err_str[buff_size];
 
 #ifdef _WIN32
     FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM, nullptr, GetLastError(),
                    MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), err_str, buff_size, nullptr);
+    return std::string(err_str, buff_size);
+#elif defined(__GLIBC__) && (_GNU_SOURCE || (_POSIX_C_SOURCE < 200112L && _XOPEN_SOURCE < 600))
+    // Thread safe (GNU-specific)
+    const char* str = strerror_r(errno, err_str, buff_size);
+    return std::string(str);
 #else
     // Thread safe (XSI-compliant)
-    strerror_r(errno, err_str, buff_size);
+    const int success = strerror_r(errno, err_str, buff_size);
+    if (success != 0) {
+        return {};
+    }
+    return std::string(err_str);
 #endif
-
-    return std::string(err_str, buff_size);
 }
diff --git a/src/common/stream.h b/src/common/stream.h
index 2585c16af..0e40692de 100644
--- a/src/common/stream.h
+++ b/src/common/stream.h
@@ -21,6 +21,12 @@ public:
     explicit Stream();
     ~Stream();
 
+    Stream(const Stream&) = delete;
+    Stream& operator=(const Stream&) = delete;
+
+    Stream(Stream&&) = default;
+    Stream& operator=(Stream&&) = default;
+
     /// Reposition bitstream "cursor" to the specified offset from origin
     void Seek(s32 offset, SeekOrigin origin);
 
@@ -30,15 +36,15 @@ public:
     /// Writes byte at current position
     void WriteByte(u8 byte);
 
-    std::size_t GetPosition() const {
+    [[nodiscard]] std::size_t GetPosition() const {
         return position;
     }
 
-    std::vector<u8>& GetBuffer() {
+    [[nodiscard]] std::vector<u8>& GetBuffer() {
         return buffer;
     }
 
-    const std::vector<u8>& GetBuffer() const {
+    [[nodiscard]] const std::vector<u8>& GetBuffer() const {
         return buffer;
     }
 
diff --git a/src/common/string_util.cpp b/src/common/string_util.cpp
index 84883a1d3..4cba2aaa4 100644
--- a/src/common/string_util.cpp
+++ b/src/common/string_util.cpp
@@ -8,6 +8,7 @@
 #include <cstdlib>
 #include <locale>
 #include <sstream>
+
 #include "common/common_paths.h"
 #include "common/logging/log.h"
 #include "common/string_util.h"
@@ -21,14 +22,14 @@ namespace Common {
 /// Make a string lowercase
 std::string ToLower(std::string str) {
     std::transform(str.begin(), str.end(), str.begin(),
-                   [](unsigned char c) { return std::tolower(c); });
+                   [](unsigned char c) { return static_cast<char>(std::tolower(c)); });
     return str;
 }
 
 /// Make a string uppercase
 std::string ToUpper(std::string str) {
     std::transform(str.begin(), str.end(), str.begin(),
-                   [](unsigned char c) { return std::toupper(c); });
+                   [](unsigned char c) { return static_cast<char>(std::toupper(c)); });
     return str;
 }
 
diff --git a/src/common/timer.cpp b/src/common/timer.cpp
index 2dc15e434..d17dc2a50 100644
--- a/src/common/timer.cpp
+++ b/src/common/timer.cpp
@@ -142,20 +142,18 @@ std::string Timer::GetTimeFormatted() {
 // ----------------
 double Timer::GetDoubleTime() {
     // Get continuous timestamp
-    u64 TmpSeconds = static_cast<u64>(Common::Timer::GetTimeSinceJan1970().count());
-    double ms = static_cast<u64>(GetTimeMs().count()) % 1000;
+    auto tmp_seconds = static_cast<u64>(GetTimeSinceJan1970().count());
+    const auto ms = static_cast<double>(static_cast<u64>(GetTimeMs().count()) % 1000);
 
     // Remove a few years. We only really want enough seconds to make
     // sure that we are detecting actual actions, perhaps 60 seconds is
     // enough really, but I leave a year of seconds anyway, in case the
     // user's clock is incorrect or something like that.
-    TmpSeconds = TmpSeconds - (38 * 365 * 24 * 60 * 60);
+    tmp_seconds = tmp_seconds - (38 * 365 * 24 * 60 * 60);
 
     // Make a smaller integer that fits in the double
-    u32 Seconds = static_cast<u32>(TmpSeconds);
-    double TmpTime = Seconds + ms;
-
-    return TmpTime;
+    const auto seconds = static_cast<u32>(tmp_seconds);
+    return seconds + ms;
 }
 
 } // Namespace Common
diff --git a/src/common/wall_clock.cpp b/src/common/wall_clock.cpp
index 7a20e95b7..452a2837e 100644
--- a/src/common/wall_clock.cpp
+++ b/src/common/wall_clock.cpp
@@ -53,7 +53,7 @@ public:
         return Common::Divide128On32(temporary, 1000000000).first;
     }
 
-    void Pause(bool is_paused) override {
+    void Pause([[maybe_unused]] bool is_paused) override {
         // Do nothing in this clock type.
     }
 
diff --git a/src/common/x64/native_clock.h b/src/common/x64/native_clock.h
index 7c503df26..97aab6ac9 100644
--- a/src/common/x64/native_clock.h
+++ b/src/common/x64/native_clock.h
@@ -34,7 +34,7 @@ private:
     /// value used to reduce the native clocks accuracy as some apss rely on
     /// undefined behavior where the level of accuracy in the clock shouldn't
     /// be higher.
-    static constexpr u64 inaccuracy_mask = ~(0x400 - 1);
+    static constexpr u64 inaccuracy_mask = ~(UINT64_C(0x400) - 1);
 
     SpinLock rtsc_serialize{};
     u64 last_measure{};