If a pattern variable is never defined in a capture, it should be removed altogether, since any substitution will be replaced by the empty string. Emitting a pattern generation error in this case will help eliminate errors caused by misspelled variable names in specifications.
If a pattern variable is never defined in a capture, it should be removed altogether, since any substitution will be replaced by the empty string. Emitting a pattern generation error in this case will help eliminate errors caused by misspelled variable names in specifications.