Fix all warnings on Linux

[hungptit]

Problem

I got these warnings when compiling re-flex on Linux (gcc-14.2.1).

make[2]: Entering directory '/home/hungptit/working/ioutils/.local/build/reflex/tests'
g++ -DHAVE_CONFIG_H -I. -I/home/hungptit/working/ioutils/_deps/reflex-src/tests -I..  -I/home/hungptit/working/ioutils/_deps/reflex-src/include   -Wall -Wextra -Wunused -O2 -MT rtest-rtest.o -MD -MP -MF .deps/rtes
t-rtest.Tpo -c -o rtest-rtest.o `test -f 'rtest.cpp' || echo '/home/hungptit/working/ioutils/_deps/reflex-src/tests/'`rtest.cpp
In file included from /home/hungptit/working/ioutils/_deps/reflex-src/tests/rtest.cpp:7:
/home/hungptit/working/ioutils/_deps/reflex-src/include/reflex/matcher.h:112:20: warning: ‘virtual reflex::Matcher& reflex::Matcher::operator=(const reflex::Matcher&)’ was hidden [-Woverloaded-virtual=]
  112 |   virtual Matcher& operator=(const Matcher& matcher) ///< matcher to copy
      |                    ^~~~~~~~               
/home/hungptit/working/ioutils/_deps/reflex-src/tests/rtest.cpp:31:7: note:   by ‘WrappedMatcher::operator=’
   31 | class WrappedMatcher : public Matcher {                                                                                                                                                                      
      |       ^~~~~~~~~~~~~~                                                                              
In file included from /home/hungptit/working/ioutils/_deps/reflex-src/include/reflex/matcher.h:40:                                                                                                                   
/home/hungptit/working/ioutils/_deps/reflex-src/include/reflex/absmatcher.h:1694:27: warning: ‘reflex::PatternMatcher<P>& reflex::PatternMatcher<P>::operator=(const reflex::PatternMatcher<P>&) [with P = reflex::Pa
ttern]’ was hidden [-Woverloaded-virtual=]                                                                
 1694 |   virtual PatternMatcher& operator=(const PatternMatcher& matcher) ///< matcher with pattern to use (pattern may be shared)
      |                           ^~~~~~~~                                                                
/home/hungptit/working/ioutils/_deps/reflex-src/tests/rtest.cpp:31:7: note:   by ‘WrappedMatcher::operator=’
   31 | class WrappedMatcher : public Matcher {                                                           
      |       ^~~~~~~~~~~~~~                                                   

Solution

Remove the virtual keywords in related template classes.

[genivia-inc]

Thank you for your feedback. I am not sure this is the right thing to do. What may cause the warning is located in abslexer.h, which can be updated by adding this at line 74 to the class Matcher : public M scope:

    /// Assign a matcher, the underlying pattern object is shared (not deep copied).
    virtual Matcher& operator=(const Matcher& matcher)
    {
      M::operator=(matcher);
      lexer_ = matcher.lexer_;
      return *this;
    }