diff --git a/src/core/Bag.pm b/src/core/Bag.pm
index e7de21a69b1..ddf3fce4720 100644
--- a/src/core/Bag.pm
+++ b/src/core/Bag.pm
@@ -22,27 +22,7 @@ my class Bag does Baggy {
         )
     }
 
-#--- object creation methods
-    multi method new(Bag:_:) {
-        nqp::if(
-          nqp::eqaddr(self.WHAT,Bag),
-          bag(),
-          nqp::create(self)
-        )
-    }
-
 #--- interface methods
-    method SET-SELF(Bag:D: \elems) {
-        nqp::if(
-          nqp::elems(elems),
-          nqp::stmts(
-            nqp::bindattr(self,::?CLASS,'$!elems',elems),
-            self
-          ),
-          bag()
-        )
-    }
-
     multi method DELETE-KEY(Bag:D: \k) {
         X::Immutable.new(method => 'DELETE-KEY', typename => self.^name).throw;
     }
diff --git a/src/core/BagHash.pm b/src/core/BagHash.pm
index 2508549fba5..50cbd3063d3 100644
--- a/src/core/BagHash.pm
+++ b/src/core/BagHash.pm
@@ -55,9 +55,6 @@ my class BagHash does Baggy {
         )
     }
 
-#--- object creation methods
-    multi method new(BagHash:_:) { nqp::create(self) }
-
 #--- introspection methods
     method total() { Rakudo::QuantHash.BAG-TOTAL($!elems) }
 
diff --git a/src/core/Baggy.pm b/src/core/Baggy.pm
index dc37bfed57d..51d0cd0af94 100644
--- a/src/core/Baggy.pm
+++ b/src/core/Baggy.pm
@@ -12,15 +12,6 @@ my role Baggy does QuantHash {
 # Immutables aspects of Bag/Mix, need to live to Bag/Mix respectively.
 
 #--- interface methods
-    method SET-SELF(Baggy:D: \elems) {
-        nqp::stmts(
-          nqp::if(
-            nqp::elems(elems),
-            nqp::bindattr(self,::?CLASS,'$!elems',elems)
-          ),
-          self
-        )
-    }
     multi method ACCEPTS(Baggy:U: \other --> Bool:D) {
         other.^does(self)
     }
diff --git a/src/core/Iterable.pm b/src/core/Iterable.pm
index 198be53152f..3fd51431821 100644
--- a/src/core/Iterable.pm
+++ b/src/core/Iterable.pm
@@ -142,9 +142,15 @@ my role Iterable {
         nqp::if(
           (my $iterator := iterable.flat.iterator).is-lazy,
           Failure.new(X::Cannot::Lazy.new(:action<coerce>,:what(type.^name))),
-          nqp::create(type).SET-SELF(
-            Rakudo::QuantHash.ADD-PAIRS-TO-MIX(
+          nqp::if(
+            nqp::elems(my $elems := Rakudo::QuantHash.ADD-PAIRS-TO-MIX(
               nqp::create(Rakudo::Internals::IterationSet),$iterator
+            )),
+            nqp::create(type).SET-SELF($elems),
+            nqp::if(
+              nqp::eqaddr(type,Mix),
+              mix(),
+              nqp::create(type)
             )
           )
         )
@@ -156,9 +162,15 @@ my role Iterable {
         nqp::if(
           (my $iterator := iterable.flat.iterator).is-lazy,
           Failure.new(X::Cannot::Lazy.new(:action<coerce>,:what(type.^name))),
-          nqp::create(type).SET-SELF(
-            Rakudo::QuantHash.ADD-PAIRS-TO-BAG(
+          nqp::if(
+            nqp::elems(my $elems := Rakudo::QuantHash.ADD-PAIRS-TO-BAG(
               nqp::create(Rakudo::Internals::IterationSet),$iterator
+            )),
+            nqp::create(type).SET-SELF($elems),
+            nqp::if(
+              nqp::eqaddr(type,Bag),
+              bag(),
+              nqp::create(type)
             )
           )
         )
@@ -170,9 +182,15 @@ my role Iterable {
         nqp::if(
           (my $iterator := iterable.flat.iterator).is-lazy,
           Failure.new(X::Cannot::Lazy.new(:action<coerce>,:what(type.^name))),
-          nqp::create(type).SET-SELF(
-            Rakudo::QuantHash.ADD-PAIRS-TO-SET(
+          nqp::if(
+            nqp::elems(my $elems := Rakudo::QuantHash.ADD-PAIRS-TO-SET(
               nqp::create(Rakudo::Internals::IterationSet),$iterator
+            )),
+            nqp::create(type).SET-SELF($elems),
+            nqp::if(
+              nqp::eqaddr(type,Set),
+              set(),
+              nqp::create(type)
             )
           )
         )
diff --git a/src/core/Mix.pm b/src/core/Mix.pm
index 95b36f32550..b4762c40ef3 100644
--- a/src/core/Mix.pm
+++ b/src/core/Mix.pm
@@ -4,17 +4,6 @@ my class Mix does Mixy {
     has Real $!total-positive;
 
 #--- interface methods
-    method SET-SELF(Mix:D: \elems) {
-        nqp::if(
-          nqp::elems(elems),
-          nqp::stmts(
-            nqp::bindattr(self,::?CLASS,'$!elems',elems),
-            self
-          ),
-          mix()
-        )
-    }
-
     multi method DELETE-KEY(Mix:D: \k) {
         X::Immutable.new(method => 'DELETE-KEY', typename => self.^name).throw;
     }
@@ -46,15 +35,6 @@ my class Mix does Mixy {
         )
     }
 
-#--- object creation methods
-    multi method new(Mix:_:) {
-        nqp::if(
-          nqp::eqaddr(self.WHAT,Mix),
-          mix(),
-          nqp::create(self)
-        )
-    }
-
 #--- selection methods
     multi method grab($count? --> Real:D) {
         X::Immutable.new( method => 'grab', typename => self.^name ).throw;
diff --git a/src/core/QuantHash.pm b/src/core/QuantHash.pm
index 4ce44add492..66574d54b22 100644
--- a/src/core/QuantHash.pm
+++ b/src/core/QuantHash.pm
@@ -1,4 +1,15 @@
 my role QuantHash does Associative {
+
+    method SET-SELF(QuantHash:D: \elems) {
+        nqp::stmts(
+          nqp::if(
+            nqp::elems(elems),
+            nqp::bindattr(self,::?CLASS,'$!elems',elems)
+          ),
+          self
+        )
+    }
+
     method Int     ( --> Int:D)     { self.total.Int }
     method Num     ( --> Num:D)     { self.total.Num }
     method Numeric ( --> Numeric:D) { self.total.Numeric }
diff --git a/src/core/Set.pm b/src/core/Set.pm
index 4bd6769ab85..f83552172a7 100644
--- a/src/core/Set.pm
+++ b/src/core/Set.pm
@@ -1,24 +1,6 @@
 my class Set does Setty {
     has $!WHICH;
 
-    method SET-SELF(\elems) {
-        nqp::if(
-          nqp::elems(elems),
-          nqp::stmts(
-            nqp::bindattr(self,::?CLASS,'$!elems',elems),
-            self
-          ),
-          set()
-        )
-    }
-    multi method new(Set:_:) {
-        nqp::if(
-          nqp::eqaddr(self.WHAT,Set),
-          set(),
-          nqp::create(self)
-        )
-    }
-
     multi method WHICH (Set:D:) {
         nqp::if(
           nqp::attrinited(self,Set,'$!WHICH'),
diff --git a/src/core/SetHash.pm b/src/core/SetHash.pm
index 2400d5a6f85..5d954512c0b 100644
--- a/src/core/SetHash.pm
+++ b/src/core/SetHash.pm
@@ -1,15 +1,5 @@
 my class SetHash does Setty {
 
-    method SET-SELF(\elems) {
-        nqp::stmts(
-          nqp::if(
-            nqp::elems(elems),
-            nqp::bindattr(self,::?CLASS,'$!elems',elems)
-          ),
-          self
-        )
-    }
-
 #--- selector methods
 
     multi method grab(SetHash:D:) {