prevent a parse of '$a ' x $n becoming pathological with increasing $n (symbol extraction)
prevent a parse of 'or ' x $n becoming pathological with increasing $n (forced bareword detection)
prevent a parse of '$#a ' x $n becoming pathological with increasing $n (array index tokenization)
prevent a parse of '-a ' x $n becoming pathological with increasing $n (dashed word tokenization)
prevent a parse of '<<"a" ' x $n becoming pathological with increasing $n (heredoc start tokenization)
prevent a parse of '-a::a ' x $n becoming pathological with increasing $n (charwise word tokenization)
prevent a parse of '{}<>' x $n becoming pathological with increasing $n (glob detection)
prevent a parse of '1x ' x $n becoming pathological with increasing $n (x operator detection)
prevent a parse of 'sub() ' x $n becoming pathological with increasing $n (prototype tokenization)
create mgc version of $CURLY_SYMBOL_MGC for coming optimizations
prevent a parse of '*{' x $n becoming pathological with increasing $n (magic vs glob cast)
prevent a parse of '${' x $n becoming pathological with increasing $n (magic scalar detection)
prevent a parse of '@{' x $n becoming pathological with increasing $n (magic array detection)
prevent a parse of '%{' x $n becoming pathological with increasing $n (magic hash detection)
prevent a parse of '$${' x $n becoming pathological with increasing $n (magic deref detection)
prevent a parse of '${' x $n becoming pathological with increasing $n (magic control value detection)
replace old curly_symbol with new mgc curly_symbol
prevent a parse of 'v1a ' x $n becoming pathological with increasing $n (v-string detection)
prevent a parse of 'a<<' x $n becoming pathological with increasing $n (heredoc/bit-shift detection)