Not quite.
use v5.20;
is closer to
BEGIN { require v5.20; }
no feature qw( :all ); # `use v5.10;`+
use feature qw( :5.20 ); # `use v5.10;`+
use strict; # `use v5.12;`+
#use warnings; # `use v5.35;`+
So you want
require v5.20;
feature->unimport::out_of( $caller, ':all' ); # `use v5.10;`+
feature->import::into( $caller, ':5.20' ); # `use v5.10;`+
strict->import::into( $caller ); # `use v5.12;`+
#warnings->import::into( $caller ); # `use v5.35;`+
Turning off all features first is especially important with 5.35+ because use v5.35; and higher turn off features which are enabled by default. Specifically,
- use v5.35; and higher turns off the indirect and multidimensional normally-enabled features, and
- use v5.37; and higher turns off the bareword_filehandles normally-enabled feature
$ perl -e'use v5.35; abc def;'
Bareword found where operator expected (Do you need to predeclare "abc
+"?) at -e line 1, near "abc def"
syntax error at -e line 1, near "abc def"
Execution of -e aborted due to compilation errors.
$ perl -e'use feature qw( :5.35 ); abc def;'
Can't locate object method "abc" via package "def" (perhaps you forgot
+ to load "def"?) at -e line 1.
$ perl -e'no feature qw( :all ); use feature qw( :5.35 ); abc def;'
Bareword found where operator expected (Do you need to predeclare "abc
+"?) at -e line 1, near "abc def"
syntax error at -e line 1, near "abc def"
Execution of -e aborted due to compilation errors.
