reduce with postcircumfix

fixing-decont.diff

         sub (+values) {
             my $iter := values.iterator;
-            nqp::if(
-              nqp::eqaddr((my $result := $iter.pull-one),IterationEnd),
+            return nqp::if(
+              nqp::eqaddr(nqp::decont(my $result = $iter.pull-one),IterationEnd),
               op.(),                         # identity
               nqp::if(
-                nqp::eqaddr((my $value := $iter.pull-one),IterationEnd),
+                nqp::eqaddr(nqp::decont(my $value = $iter.pull-one),IterationEnd),
                 nqp::if(
                   nqp::isle_i(op.arity,1),
                   op.($result),              # can call with 1 param
                   $result                    # what we got
                 ),
                 nqp::stmts(
-                  ($result := op.($result,$value)),
+                  ($result = op.($result,$value)),
                   nqp::until(
-                    nqp::eqaddr(($value := $iter.pull-one),IterationEnd),
-                    ($result := op.($result,$value))
+                    nqp::eqaddr(nqp::decont($value = $iter.pull-one),IterationEnd),
+                    ($result = op.($result, $value))
                   ),
                   $result                    # final result
                 )

r2000.raku

my %hash;
my @path = <a b c>;
#my @path = ('a', Any, 'b', Any);
my $value = 42;

my $slot := (%hash, |@path).reduce: &postcircumfix:<{ }>;

dd :$slot, :contoto($slot.VAR.^name), :type($slot.WHAT.raku);

$slot = $value;  # ERROR: Cannot assign to an immutable value
say %hash;       # EXPECTED: {a => {b => {c => 42}}}