Improve Error Reporting of SemVer Parser

liblangutil/SemVerHandler.h

@@ -25,17 +25,18 @@
 
 #include <liblangutil/Token.h>
 #include <libsolutil/Assertions.h>
+#include <liblangutil/Exceptions.h>
 
 #include <string>
-#include <optional>
 #include <utility>
 #include <vector>
 
 namespace solidity::langutil
 {
 
-class SemVerError: public util::Exception
+struct SemVerError: public util::Exception
 {
+
 };
 
 #undef major
@@ -87,8 +88,8 @@ class SemVerMatchExpressionParser
 public:
 	SemVerMatchExpressionParser(std::vector<Token> _tokens, std::vector<std::string> _literals);
 
-	/// Returns an expression if it was parseable, or nothing otherwise.
-	std::optional<SemVerMatchExpression> parse();
+	/// Returns an expression if it was parsable, or throws a SemVerError otherwise.
+	SemVerMatchExpression parse();
 
 private:
 	void reset();