Global aliases are now substituted in all locations, including part of compound commands where only operators are syntactically acceptable.
The shell now reads and executes all shell commands line by line. Previously, commands that are not from a file or the standard input were parsed all at once before being executed.
After alias substitution where the alias value ends with a blank, the next word is also subject to alias substitution, but previously this substitution was being applied only once, which was a different behavior from many other shells.
After alias substitution where the alias value ends with a blank, global aliases were being applied twice, which is now just once.
Line continuations no longer prevent recursive alias substitution.