Remove file_error and duplicate nodiscard

src/utils/common.hpp

@@ -35,14 +35,6 @@
  #error "Unsupported compiler"
 #endif
 
-#if IS_GCC || IS_CLANG
- #define NODISCARD __attribute__((warn_unused_result))
-// #elif IS_MSVC && _MSC_VER >= 1700
-//  #define NODISCARD _Check_return_
-#else
- #define NODISCARD
-#endif
-
 #include <cstdio>
 #include <stdexcept>
 #include <string>

src/utils/error.hpp

@@ -28,11 +28,6 @@ namespace detail {
         }
     };
 
-    class file_error : public internal_error {
-    public:
-        file_error(std::string path) : internal_error("Unable to read file " + std::move(path)) {}
-    };
-
     // Lightweight std::source_location.
     struct source_location {
         const char* const file;