"as above" is unclear. I think you meant "my is conditional", but it's really "my always executed" (in the scope in which it resides).

c() or my $x;       # XXX Conditionally executed
c() and my $x;      # XXX Conditionally executed
my $x if c();       # XXX Conditionally executed (same as previous)
sub foo { my $x }   # OK  Always executed
if (c()) { my $x }  # OK  Always executed
die; my $x;         # OK  Always executed
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