* right assignment: use existing AST node types (#738)

doc/AST_FORMAT.md

@@ -735,9 +735,10 @@ Format:
 Format:
 
 ~~~
-(rasgn (int 1) (lvasgn :a))
+(lvasgn :a (int 1))
 "1 => a"
  ~~~~~~ expression
+      ~ name
    ~~ operator
 ~~~
 
@@ -746,7 +747,7 @@ Format:
 Format:
 
 ~~~
-(mrasgn (send (int 13) :divmod (int 5)) (mlhs (lvasgn :a) (lvasgn :b)))
+(masgn (mlhs (lvasgn :a) (lvasgn :b)) (send (int 13) :divmod (int 5)))
 "13.divmod(5) => a,b"
  ~~~~~~~~~~~~~~~~~~~ expression
               ^^ operator

lib/parser/ast/processor.rb

@@ -75,9 +75,6 @@ def on_op_asgn(node)
       alias on_mlhs     process_regular_node
       alias on_masgn    process_regular_node
 
-      alias on_rasgn    process_regular_node
-      alias on_mrasgn   process_regular_node
-
       def on_const(node)
         scope_node, name = *node
 

lib/parser/builders/default.rb

@@ -656,12 +656,11 @@ def multi_assign(lhs, eql_t, rhs)
     end
 
     def rassign(lhs, assoc_t, rhs)
-      n(:rasgn, [lhs, rhs], binary_op_map(lhs, assoc_t, rhs))
+      assign(rhs, assoc_t, lhs)
     end
 
     def multi_rassign(lhs, assoc_t, rhs)
-      n(:mrasgn, [ lhs, rhs ],
-        binary_op_map(lhs, assoc_t, rhs))
+      multi_assign(rhs, assoc_t, lhs)
     end
 
     #

lib/parser/meta.rb

@@ -12,7 +12,7 @@ module Meta
         sym dsym xstr regopt regexp array splat
         pair kwsplat hash irange erange self
         lvar ivar cvar gvar const defined? lvasgn
-        ivasgn cvasgn gvasgn casgn mlhs masgn rasgn mrasgn
+        ivasgn cvasgn gvasgn casgn mlhs masgn
         op_asgn and_asgn ensure rescue arg_expr
         or_asgn back_ref nth_ref
         match_with_lvasgn match_current_line

lib/parser/source/comment/associator.rb

@@ -107,7 +107,7 @@ def associate_locations
 
       private
 
-      POSTFIX_TYPES = Set[:if, :while, :while_post, :until, :until_post].freeze
+      POSTFIX_TYPES = Set[:if, :while, :while_post, :until, :until_post, :masgn].freeze
       def children_in_source_order(node)
         if POSTFIX_TYPES.include?(node.type)
           # All these types have either nodes with expressions, or `nil`

test/test_parser.rb

@@ -9688,17 +9688,16 @@ def test_endless_method_with_rescue_mod
 
   def test_rasgn
     assert_parses(
-      s(:rasgn,
-        s(:int, 1), s(:lvasgn, :a)),
+      s(:lvasgn, :a,
+        s(:int, 1)),
       %q{1 => a},
       %q{~~~~~~ expression
         |  ^^ operator},
       SINCE_3_0)
 
     assert_parses(
-      s(:rasgn,
-        s(:send, s(:int, 1), :+, s(:int, 2)),
-        s(:gvasgn, :$a)),
+      s(:gvasgn, :$a,
+        s(:send, s(:int, 1), :+, s(:int, 2))),
       %q{1 + 2 => $a},
       %q{~~~~~~~~~~~ expression
         |      ^^ operator},
@@ -9707,22 +9706,23 @@ def test_rasgn
 
   def test_mrasgn
     assert_parses(
-      s(:mrasgn,
-        s(:send, s(:int, 13), :divmod, s(:int, 5)),
-        s(:mlhs, s(:lvasgn, :a), s(:lvasgn, :b))),
+      s(:masgn,
+        s(:mlhs, s(:lvasgn, :a), s(:lvasgn, :b)),
+        s(:send, s(:int, 13), :divmod, s(:int, 5))),
       %q{13.divmod(5) => a,b},
       %q{~~~~~~~~~~~~~~~~~~~ expression
         |             ^^ operator},
       SINCE_3_0)
 
     assert_parses(
-      s(:mrasgn,
-        s(:mrasgn,
-          s(:send, s(:int, 13), :divmod, s(:int, 5)),
-          s(:mlhs, s(:lvasgn, :a), s(:lvasgn, :b))),
-        s(:mlhs, s(:lvasgn, :c), s(:lvasgn, :d))),
+      s(:masgn,
+        s(:mlhs, s(:lvasgn, :c), s(:lvasgn, :d)),
+        s(:masgn,
+          s(:mlhs, s(:lvasgn, :a), s(:lvasgn, :b)),
+          s(:send, s(:int, 13), :divmod, s(:int, 5))),
+        ),
       %q{13.divmod(5) => a,b => c, d},
-      %q{~~~~~~~~~~~~~~~~~~~ expression (mrasgn)
+      %q{~~~~~~~~~~~~~~~~~~~ expression (masgn)
         |~~~~~~~~~~~~~~~~~~~~~~~~~~~ expression},
       SINCE_3_0)
   end