What happens inside Ruby when a method is called (method dispatch pipeline)?

Ruby resolves method calls through a lookup chain involving caches, singleton class, ancestors, and method tables.

When a method is called, Ruby first checks inline method caches. If missed, it performs method lookup starting from the receiver's singleton class, then class, then included modules (in reverse include order), then superclasses. Once found, the method entry is cached for future calls. This cache dramatically improves performance in hot paths.