Fix unbalanced parenthesis crash in Common Lisp lexer #1129
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The Common Lisp lexer attempted to guard against an unmatched closing parenthesis being used by checking whether the stack of states was empty. This misunderstood the way the stack is used. The stack should always have at least one state (the bottom-most :root state). Popping this state will cause an empty stack error to be thrown (as noted in rouge-ruby#1102). The correct guard is to check whether the size of the stack is 1. If it is, then we have an unmatched closing parenthesis and should generate an error token. This fixes rouge-ruby#1102.
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The Common Lisp lexer attempted to guard against an unmatched closing parenthesis being used by checking whether the stack of states was empty.
This misunderstood the way the stack is used. The stack should always have at least one state (the bottom-most :root state). Popping this state will cause an empty stack error to be thrown (as noted in #1102).
The correct guard is to check whether the size of the stack is 1. If it is, then we have an unmatched closing parenthesis and should generate an error token. This fixes #1102.