diff --git a/ml.cpp b/ml.cpp
index 098c5e9..a962859 100644
--- a/ml.cpp
+++ b/ml.cpp
@@ -633,10 +633,6 @@ std::string MlError::description() const {
            "error: the expression `" + cause->debug() + "` with message \"" + msg + "\"";
 }
 
-const char* MlError::what() const noexcept {
-    return ("error: the expression `" + cause->debug() + "` with message \"" + msg + "\"").c_str();
-}
-
 void MlEnvironment::combine(MlEnvironment const &other) {
 	// Normally, I would use the `insert` method of the `map` class,
 	// but it doesn't overwrite previously declared values for keys.
@@ -2130,7 +2126,7 @@ int main(int argc, char *argv[]) {
 		return 0;
 		
 	} catch (MlError &e) {
-		std::cerr << e.what() << std::endl;
+		std::cerr << e.description() << std::endl;
 	} catch (const std::exception &e) {
 		std::cerr << MlPerfMon::instance().callstack() << e.what() << std::endl;
 		MlPerfMon::instance().clear_callstack();
diff --git a/ml.h b/ml.h
index 056276c..8d81575 100644
--- a/ml.h
+++ b/ml.h
@@ -83,9 +83,6 @@ public:
     // Get the printable error description.
     std::string description() const;
 
-    // inherited from std::exception 
-    virtual const char* what() const noexcept;
-
 private:
     MlValue *cause;
     MlEnvironment env;