diff.diff

diff --git a/src/Perl6/Optimizer.nqp b/src/Perl6/Optimizer.nqp
index 74fbd0a..6b27087 100644
--- a/src/Perl6/Optimizer.nqp
+++ b/src/Perl6/Optimizer.nqp
@@ -1692,12 +1692,16 @@ class Perl6::Optimizer {
                     }
                 }
             }
-            elsif $!level >= 2 && (
-                 $op.name eq '&prefix:<++>' || $op.name eq '&postfix:<++>'
-              || $op.name eq '&prefix:<-->' || $op.name eq '&postfix:<-->'
-            ) && $!symbols.is_from_core($op.name)
-            && self.optimize-post-pre-inc-dec-ops($op) -> $qast {
-                return $qast;
+            elsif $!symbols.is_from_core($op.name) {
+              if $!level >= 2 && (
+                   $op.name eq '&prefix:<++>' || $op.name eq '&postfix:<++>'
+                || $op.name eq '&prefix:<-->' || $op.name eq '&postfix:<-->'
+              ) && self.optimize-post-pre-inc-dec-ops($op) -> $qast {
+                  return $qast;
+              }
+              elsif self.optimize-special-core-routine-calls($op, $obj) -> $qast {
+                  return $qast
+              }
             }
             # If it's an onlystar proto, we have a couple of options.
             # The first is that we may be able to work out what to
@@ -1781,6 +1785,16 @@ class Perl6::Optimizer {
         return NQPMu;
     }
 
+    method optimize-special-core-routine-calls($op, $routine) {
+        my $name := $op.name;
+        if $op.elems == 0 && ($name eq '&set' || $name eq '&bag' || $name eq '&mix') {
+            # argless set/bag/mix return an interned BEGIN-inited object, so we can just
+            # execute the call right now and stick that object in place of call
+            return QAST::WVal.new: value => $routine()
+        }
+        NQPMu
+    }
+
     method optimize-post-pre-inc-dec-ops($op) {
         my $var  := $op[0];
         my $node := $op.node;
diff --git a/src/core/set_operators.pm6 b/src/core/set_operators.pm6
index 7da80a9..891e1a7 100644
--- a/src/core/set_operators.pm6
+++ b/src/core/set_operators.pm6
@@ -1,13 +1,25 @@
 proto sub set(|) {*}
-multi sub set() { BEGIN nqp::create(Set) }
+multi sub set() {
+    # Note: static optimizer constant-folds this candidate. If making changes here, ensure that
+    # constant-folding it still makes sense or remove constant-folding in static optimizer.
+    BEGIN nqp::create(Set)
+}
 multi sub set(*@a --> Set:D) { Set.new(@a) }
 
 proto sub bag(|) {*}
-multi sub bag() { BEGIN nqp::create(Bag) }
+multi sub bag() {
+    # Note: static optimizer constant-folds this candidate. If making changes here, ensure that
+    # constant-folding it still makes sense or remove constant-folding in static optimizer.
+    BEGIN nqp::create(Bag)
+}
 multi sub bag(*@a --> Bag:D) { Bag.new(@a) }
 
 proto sub mix(|) {*}
-multi sub mix() { BEGIN nqp::create(Mix) }
+multi sub mix() {
+    # Note: static optimizer constant-folds this candidate. If making changes here, ensure that
+    # constant-folding it still makes sense or remove constant-folding in static optimizer.
+    BEGIN nqp::create(Mix)
+}
 multi sub mix(*@a --> Mix:D) { Mix.new(@a) }
 
 # vim: ft=perl6 expandtab sw=4