Revert "Method reference operator"

This reverts commit 67c5747369.
[Feature #16275]

NEWS

@@ -186,9 +186,6 @@ sufficient information, see the ChangeLog file or Redmine
     # Previously parsed as: (a, b = raise) rescue [1, 2]
     # Now parsed as:         a, b = (raise rescue [1, 2])
 
-* Method reference operator, <code>.:</code> is introduced as an
-  experimental feature.  [Feature #12125] [Feature #13581]
-
 * +yield+ in singleton class syntax is warned and will be deprecated later [Feature #15575].
 
 * Argument forwarding by <code>(...)</code> is introduced. [Feature #16253]

ast.c

@@ -432,9 +432,6 @@ node_children(rb_ast_t *ast, NODE *node)
                                     NEW_CHILD(ast, node->nd_args));
       case NODE_VCALL:
         return rb_ary_new_from_args(1, ID2SYM(node->nd_mid));
-      case NODE_METHREF:
-        return rb_ary_new_from_args(2, NEW_CHILD(ast, node->nd_recv),
-                                    ID2SYM(node->nd_mid));
       case NODE_SUPER:
         return rb_ary_new_from_node_args(ast, 1, node->nd_args);
       case NODE_ZSUPER:

compile.c

@@ -4742,11 +4742,9 @@ defined_expr0(rb_iseq_t *iseq, LINK_ANCHOR *const ret,
       case NODE_OPCALL:
       case NODE_VCALL:
       case NODE_FCALL:
-      case NODE_METHREF:
       case NODE_ATTRASGN:{
 	const int explicit_receiver =
 	    (type == NODE_CALL || type == NODE_OPCALL ||
-             type == NODE_METHREF ||
 	     (type == NODE_ATTRASGN && !private_recv_p(node)));
 
 	if (!lfinish[1] && (node->nd_args || explicit_receiver)) {
@@ -8484,13 +8482,6 @@ iseq_compile_each0(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *node, in
 	}
 	break;
       }
-      case NODE_METHREF:
-        CHECK(COMPILE(ret, "receiver", node->nd_recv));
-        ADD_ELEM(ret, &new_insn_body(iseq, line, BIN(methodref), 1, ID2SYM(node->nd_mid))->link);
-        if (popped) {
-            ADD_INSN(ret, line, pop);
-        }
-        break;
       default:
 	UNKNOWN_NODE("iseq_compile_each", node, COMPILE_NG);
       ng:

defs/id.def

@@ -130,7 +130,6 @@ token_ops = %[\
   ANDOP         &&
   OROP          ||
   ANDDOT        &.
-  METHREF       .:
 ]
 
 class KeywordError < RuntimeError

ext/objspace/objspace.c

@@ -474,7 +474,6 @@ count_nodes(int argc, VALUE *argv, VALUE os)
 		COUNT_NODE(NODE_DSYM);
 		COUNT_NODE(NODE_ATTRASGN);
 		COUNT_NODE(NODE_LAMBDA);
-                COUNT_NODE(NODE_METHREF);
                 COUNT_NODE(NODE_ARYPTN);
                 COUNT_NODE(NODE_HSHPTN);
 #undef COUNT_NODE

ext/ripper/eventids2.c

@@ -261,7 +261,6 @@ ripper_token2eventid(enum yytokentype tok)
         [tSTAR] 		= O(op),
         [tDSTAR]		= O(op),
         [tANDDOT]		= O(op),
-        [tMETHREF]		= O(op),
         [tSTRING_BEG]		= O(tstring_beg),
         [tSTRING_CONTENT]	= O(tstring_content),
         [tSTRING_DBEG]		= O(embexpr_beg),

insns.def

@@ -719,17 +719,6 @@ checktype
     ret = (TYPE(val) == (int)type) ? Qtrue : Qfalse;
 }
 
-/* get frozen method reference. */
-DEFINE_INSN
-methodref
-(ID id)
-(VALUE val)
-(VALUE ret)
-{
-    ret = rb_obj_method(val, ID2SYM(id));
-    RB_OBJ_FREEZE_RAW(ret);
-}
-
 /**********************************************************/
 /* deal with control flow 1: class/module                 */
 /**********************************************************/

lib/optparse.rb

@@ -1781,7 +1781,7 @@ XXX
       visit(:complete, typ, opt, icase, *pat) {|o, *sw| return sw}
     }
     exc = ambiguous ? AmbiguousOption : InvalidOption
-    raise exc.new(opt, additional: self.:additional_message.curry[typ])
+    raise exc.new(opt, additional: self.method(:additional_message).curry[typ])
   end
   private :complete
 

node.c

@@ -954,15 +954,6 @@ dump_node(VALUE buf, VALUE indent, int comment, const NODE * node)
 	F_NODE(nd_args, "arguments");
 	return;
 
-      case NODE_METHREF:
-        ANN("method reference");
-        ANN("format: [nd_recv].:[nd_mid]");
-        ANN("example: foo.:method");
-        F_NODE(nd_recv, "receiver");
-        LAST_NODE;
-        F_ID(nd_mid, "method name");
-        return;
-
       case NODE_LAMBDA:
 	ANN("lambda expression");
 	ANN("format: -> [nd_body]");

node.h

@@ -122,7 +122,6 @@ enum node_type {
     NODE_DSYM,
     NODE_ATTRASGN,
     NODE_LAMBDA,
-    NODE_METHREF,
     NODE_ARYPTN,
     NODE_HSHPTN,
     NODE_LAST
@@ -378,7 +377,6 @@ typedef struct RNode {
 #define NEW_PREEXE(b,loc) NEW_SCOPE(b,loc)
 #define NEW_POSTEXE(b,loc) NEW_NODE(NODE_POSTEXE,0,b,0,loc)
 #define NEW_ATTRASGN(r,m,a,loc) NEW_NODE(NODE_ATTRASGN,r,m,a,loc)
-#define NEW_METHREF(r,m,loc) NEW_NODE(NODE_METHREF,r,m,0,loc)
 
 #define NODE_SPECIAL_REQUIRED_KEYWORD ((NODE *)-1)
 #define NODE_REQUIRED_KEYWORD_P(node) ((node)->nd_value == NODE_SPECIAL_REQUIRED_KEYWORD)

parse.y

@@ -1114,7 +1114,6 @@ static int looking_at_eol_p(struct parser_params *p);
 %token tRSHFT		RUBY_TOKEN(RSHFT)  ">>"
 %token <id> tANDDOT	RUBY_TOKEN(ANDDOT) "&."
 %token <id> tCOLON2	RUBY_TOKEN(COLON2) "::"
-%token <id> tMETHREF	RUBY_TOKEN(METHREF) ".:"
 %token tCOLON3		":: at EXPR_BEG"
 %token <id> tOP_ASGN	"operator-assignment" /* +=, -=  etc. */
 %token tASSOC		"=>"
@@ -3064,13 +3063,6 @@ primary		: literal
 		    /*% %*/
 		    /*% ripper: retry! %*/
 		    }
-		| primary_value tMETHREF operation2
-		    {
-		    /*%%%*/
-			$$ = NEW_METHREF($1, $3, &@$);
-		    /*% %*/
-		    /*% ripper: methref!($1, $3) %*/
-		    }
 		;
 
 primary_value	: primary
@@ -9232,8 +9224,7 @@ parser_yylex(struct parser_params *p)
       case '.': {
         int is_beg = IS_BEG();
 	SET_LEX_STATE(EXPR_BEG);
-	switch (c = nextc(p)) {
+	if ((c = nextc(p)) == '.') {
-	  case '.':
 	    if ((c = nextc(p)) == '.') {
 		if (p->lex.paren_nest == 0 && looking_at_eol_p(p)) {
 		    rb_warn0("... at EOL, should be parenthesized?");
@@ -9242,23 +9233,6 @@ parser_yylex(struct parser_params *p)
 	    }
 	    pushback(p, c);
 	    return is_beg ? tBDOT2 : tDOT2;
-	  case ':':
-	    switch (c = nextc(p)) {
-	      default:
-		if (!parser_is_identchar(p)) break;
-		/* fallthru */
-	      case '!': case '%': case '&': case '*': case '+':
-	      case '-': case '/': case '<': case '=': case '>':
-	      case '[': case '^': case '`': case '|': case '~':
-		pushback(p, c);
-		SET_LEX_STATE(EXPR_DOT);
-		return tMETHREF;
-	      case -1:
-		break;
-	    }
-	    pushback(p, c);
-	    c = ':';
-	    break;
 	}
 	pushback(p, c);
 	if (c != -1 && ISDIGIT(c)) {

test/ripper/test_parser_events.rb

@@ -443,13 +443,6 @@ class TestRipper::ParserEvents < Test::Unit::TestCase
     assert_equal "[call(ref(self),&.,foo,[])]", tree
   end
 
-  def test_methref
-    thru_methref = false
-    tree = parse("obj.:foo", :on_methref) {thru_methref = true}
-    assert_equal true, thru_methref
-    assert_equal "[methref(vcall(obj),foo)]", tree
-  end
-
   def test_excessed_comma
     thru_excessed_comma = false
     parse("proc{|x,|}", :on_excessed_comma) {thru_excessed_comma = true}

test/ripper/test_scanner_events.rb

@@ -562,8 +562,6 @@ class TestRipper::ScannerEvents < Test::Unit::TestCase
                  scan('op', ':[]=')
     assert_equal ['&.'],
                  scan('op', 'a&.f')
-    assert_equal %w(.:),
-                 scan('op', 'obj.:foo')
     assert_equal [],
                  scan('op', %q[`make all`])
   end

test/ruby/test_ast.rb

@@ -264,15 +264,6 @@ class TestAst < Test::Unit::TestCase
     assert_equal(:SCOPE, defn.type)
   end
 
-  def test_methref
-    node = RubyVM::AbstractSyntaxTree.parse("obj.:foo")
-    _, _, body = *node.children
-    assert_equal(:METHREF, body.type)
-    recv, mid = body.children
-    assert_equal(:VCALL, recv.type)
-    assert_equal(:foo, mid)
-  end
-
   def test_dstr
     node = parse('"foo#{1}bar"')
     _, _, body = *node.children

test/ruby/test_jit.rb

@@ -482,13 +482,6 @@ class TestJIT < Test::Unit::TestCase
     end;
   end
 
-  def test_compile_insn_methodref
-    assert_compile_once("#{<<~"begin;"}\n#{<<~'end;'}", result_inspect: '"main"', insns: %i[methodref])
-    begin;
-      self.:inspect.call
-    end;
-  end
-
   def test_compile_insn_inlinecache
     assert_compile_once('Struct', result_inspect: 'Struct', insns: %i[opt_getinlinecache opt_setinlinecache])
   end

test/ruby/test_method.rb

@@ -1125,42 +1125,6 @@ class TestMethod < Test::Unit::TestCase
     }
   end
 
-  def test_method_reference_operator
-    m = 1.:succ
-    assert_predicate(m, :frozen?)
-    assert_equal(1.method(:succ), m)
-    assert_equal(2, m.())
-    m = 1.:+
-    assert_predicate(m, :frozen?)
-    assert_equal(1.method(:+), m)
-    assert_equal(42, m.(41))
-    m = 1.:-@
-    assert_predicate(m, :frozen?)
-    assert_equal(1.method(:-@), m)
-    assert_equal(-1, m.())
-    o = Object.new
-    def o.foo; 42; end
-    assert_predicate(o.:foo, :frozen?)
-    m = o.method(:foo)
-    assert_equal(m, o.:foo)
-    def o.method(m); nil; end
-    assert_equal(m, o.:foo)
-    assert_nil(o.method(:foo))
-  end
-
-  def test_method_reference_freeze_state
-    m = 1.:succ
-    assert_predicate(m, :frozen?, "dot-symbol method reference should be frozen")
-    m = 1.method(:succ)
-    assert_not_predicate(m, :frozen?, "#method method reference should not be frozen")
-    o = Object.new
-    def o.foo; 42; end
-    m = o.:foo
-    assert_predicate(m, :frozen?, "dot-symbol method reference should be frozen")
-    m = o.method(:foo)
-    assert_not_predicate(m, :frozen?, "#method method reference should not be frozen")
-  end
-
   def test_umethod_bind_call
     foo = Base.instance_method(:foo)
     assert_equal(:base, foo.bind_call(Base.new))

test/ruby/test_refinement.rb

@@ -235,7 +235,7 @@ class TestRefinement < Test::Unit::TestCase
       meth.call(3)
     EOS
     assert_equal(:refine_pow, eval_using(MethodIntegerPowEx, "2.pow(3)"))
-    assert_equal(:refine_pow, eval_using(MethodIntegerPowEx, "2.:pow.(3)"))
+    assert_equal(:refine_pow, eval_using(MethodIntegerPowEx, "2.method(:pow).(3)"))
   end
 
   module InstanceMethodIntegerPowEx

test/ruby/test_syntax.rb

@@ -93,13 +93,6 @@ class TestSyntax < Test::Unit::TestCase
     assert_valid_syntax("tap (proc do end)", __FILE__, bug9726)
   end
 
-  def test_methodref_literal
-    assert_separately [], <<-EOS
-      eval 'nil.:|;1'
-      1000.times{eval 'nil.:|;1'}
-    EOS
-  end
-
   def test_array_kwsplat_hash
     kw = {}
     h = {a: 1}
@@ -1014,10 +1007,8 @@ eom
   def test_fluent_dot
     assert_valid_syntax("a\n.foo")
     assert_valid_syntax("a\n&.foo")
-    assert_valid_syntax("a\n.:foo")
     assert_valid_syntax("a #\n#\n.foo\n")
     assert_valid_syntax("a #\n#\n&.foo\n")
-    assert_valid_syntax("a #\n#\n.:foo\n")
   end
 
   def test_safe_call_in_massign_lhs
@@ -1534,8 +1525,8 @@ eom
       assert_warning(/\A\z|:(?!#{__LINE__+1})\d+: #{warning}/o) {
         assert_equal([[], {}], obj.foo({}))
       }
-      assert_equal(-1, obj.:foo.arity)
+      assert_equal(-1, obj.method(:foo).arity)
-      parameters = obj.:foo.parameters
+      parameters = obj.method(:foo).parameters
       assert_equal(:rest, parameters.dig(0, 0))
       assert_equal(:block, parameters.dig(1, 0))
     end