Thank you for explanation.

use strict;
use warnings;
use feature 'say';
use Devel::Peek;

my $p = 'abc';
my $q = 'abc';

Dump(( substr $p, 0, 1 ) = '123' );
Dump( time );

(( substr( $q, 0, 1 )) = '123' ) = 'x';
say $q;

#substr(( time ), 0, 1 ) = 'x';

[download]

SV = IV(0xa72034) at 0xa72034
  REFCNT = 1
  FLAGS = (PADTMP,IOK,pIOK)
  IV = 1
SV = IV(0xa8bb44) at 0xa8bb44
  REFCNT = 1
  FLAGS = (PADTMP,IOK,pIOK)
  IV = 1509111305
xbc

[download]

Shouldn't the return value of list assignment operator be treated as constant, then? I tried to "sneak" various types of constants or constant-producing expressions as arg to lvalue-substr, but Perl reports compile time error (commented line).

More confusing is "xbc" -- I'd expect $q to be "123bc", and "x" to be gone into fathomless void, as in OP?

In reply to Re^2: Why Perl gets confused here? by vr
in thread Why Perl gets confused here? by vr

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