Eliminate Mu::!STORE -- we no longer do "copy pmc" semantics for values.

src/Perl6/Actions.pm

@@ -1873,10 +1873,7 @@ method term:sym<!!!>($/) {
 
 method term:sym<dotty>($/) {
     my $past := $<dotty>.ast;
-    $past.unshift(PAST::Op.new(
-        :pirop('descalarref PP'),
-        PAST::Var.new( :name('$_'), :scope('lexical') )
-    ));
+    $past.unshift(PAST::Var.new( :name('$_'), :scope('lexical') ) );
     make $past;
 }
 

src/builtins/Mu.pir

@@ -354,52 +354,6 @@ until we get roles).
 .end
 
 
-=item !STORE(source)
-
-Store C<source> into C<self>, performing type checks
-as needed.  (This method is listed with the other public
-methods simply because I expect it may switch to public
-in the future.)
-
-=cut
-
-.sub '!STORE' :method :subid('Mu::!STORE')
-    .param pmc source
-
-    # Get hold of the source object to assign.
-    $I0 = can source, 'item'
-    if $I0 goto source_fetch
-    source = deobjectref source
-    source = new ['ObjectRef'], source
-    goto have_source
-  source_fetch:
-    source = source.'item'()
-    source = deobjectref source
-  have_source:
-
-    # If source and destination are the same, we're done.
-    eq_addr self, source, store_done
-
-    # Need a type-check?
-    .local pmc type
-    type = getprop 'type', self
-    if null type goto type_check_done
-    $I0 = type.'ACCEPTS'(source)
-    unless $I0 goto type_check_failed
-
-    # All is well - do the assignment.
-  type_check_done:
-    copy self, source
-
-  store_done:
-    .return (self)
-
-  type_check_failed:
-    # XXX TODO: Awesomize this error.
-    '&die'('Type check failed for assignment')
-.end
-
-
 =item WHENCE()
 
 Return the invocant's auto-vivification closure.

src/builtins/assign.pir

@@ -24,7 +24,18 @@ src/builtins/assign.pir - assignment operations
     # If the lhs isn't a scalar container, delegate to
     # object's STORE method.
     $P0 = getprop 'scalar', cont
-    if null $P0 goto cont_store
+    unless null $P0 goto scalar_store
+    $I0 = can cont, '!STORE'
+    if $I0 goto cont_store
+
+    # We should never arrive here.  Anything that is marked 'rw'
+    # should either be a Perl6Scalar (with the 'scalar' property
+    # set) or a container that understands !STORE, such as Hash or Array.
+    # However, there's some legacy code that fails to set 'scalar',
+    # so we patch it in here to keep things going.
+    $I0 = isa cont, ['ObjectRef']
+    unless $I0 goto cont_store
+    setprop cont, 'scalar', cont
 
   scalar_store:
     # perform any needed typecheck