$ perl -Mre=debug '1 =~ `'
Freeing REx: `,'
Compiling REx `1'
size 3 first at 1
   1: EXACT <1>(3)
   3: END(0)
anchored `1' at 0 (checking anchored isall) minlen 1
Guessing start of match, REx `1' against `1'...
Found anchored substr `1' at offset 0...
Guessed: match at offset 0
Freeing REx: `1'