I don't!

Postfix constructs are not supposed to have an own scope, and local is a runtime command.

Looks like a bug to me, or at least a lack of orthogonality.

Update

Apparently are postfix constructs not alike...

• ... for has a scope but
• ... if doesn't

Bust goes the {BLOCK} scope rule....

  DB<37> @x{a..c} = 1..3

  DB<38> local $x{42} = $y++ for 1 ; say %x
c3b2a1

  DB<39> local $x{42} = $y++ if 1 ; say %x
a14211c3b2

  DB<40> say %x
a1c3b2

  DB<41> local $x = $y++ for 1 ; say $x


  DB<42> local $x = $y++ if 1 ; say $x
13

  DB<43> my $x = $y++ if 1 ; say $x
14

  DB<44> my $x = $y++ for 1 ; say $x


  DB<45>
[download]