You are slightly wrong: <code$qr = qr/./; $qr =~ m/$qr/; $qr =~ $qr;</code> is exactly identical. Again, some opcode info to illuminate. It also yields the slightly interesting form $text = 'abcd'; $text =~ qr/./ but then... maybe that's not quite normal ;-)

i  <@> leave[t1] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 5 qr.pl:1) v ->3
5     <2> sassign vKS/2 ->6
3        </> qr(/./) s ->4
-        <1> ex-rv2sv sKRM*/1 ->5
4           <> gvsv s ->5
6     <;> nextstate(main 5 qr.pl:2) v ->7

>> Here you see the $qr =~ m/$qr/ form

b     </> match() vKS ->c
-        <1> ex-rv2sv sK/1 ->8
7           <> gvsv s ->8
a        <|> regcomp(other->b) sK/1 ->b
8           <1> regcreset sK/1 ->9
-              <1> ex-rv2sv sK/1 ->a
9                 <> gvsv s ->a

>> And here you see the $qr =~ $qr form

c     <;> nextstate(main 5 qr.pl:3) v ->d
h     </> match() vKS ->i
-        <1> ex-rv2sv sK/1 ->e
d           <> gvsv s ->e
g        <|> regcomp(other->h) sK/1 ->h
e           <1> regcreset sK/1 ->f
-              <1> ex-rv2sv sK/1 ->g
f                 <> gvsv s ->g
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__SIG__
use B;
printf "You are here %08x\n", unpack "L!", unpack "P4", pack
  "L!", B::svref_2object(sub{})->OUTSIDE;
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