[Feature #19979] Method definition with `&nil`

Allow methods to declare that they don't accept a block via `&nil`.

1 files changed, 43 insertions, 0 deletions

diff --git a/test/ruby/test_syntax.rb b/test/ruby/test_syntax.rb
index e868967e8b..70e1956816 100644
--- a/test/ruby/test_syntax.rb
+++ b/test/ruby/test_syntax.rb
@@ -202,6 +202,49 @@ class TestSyntax < Test::Unit::TestCase
     assert_syntax_error("def f(...); g(&); end", /no anonymous block parameter/)
   end
 
+  def test_no_block_argument_in_method
+    assert_valid_syntax("def f(&nil) end")
+    assert_valid_syntax("def f(a, &nil) end")
+    assert_valid_syntax("def f(*rest, &nil) end")
+    assert_valid_syntax("def f(*rest, p, &nil) end")
+    assert_valid_syntax("def f(a, *rest, &nil) end")
+    assert_valid_syntax("def f(a, *rest, p, &nil) end")
+    assert_valid_syntax("def f(a, k: nil, &nil) end")
+    assert_valid_syntax("def f(a, k: nil, **kw, &nil) end")
+    assert_valid_syntax("def f(a, *rest, k: nil, &nil) end")
+    assert_valid_syntax("def f(a, *rest, k: nil, **kw, &nil) end")
+    assert_valid_syntax("def f(a, *rest, p, k: nil, &nil) end")
+    assert_valid_syntax("def f(a, *rest, p, k: nil, **kw, &nil) end")
+
+    obj = Object.new
+    obj.instance_eval "def f(&nil) end"
+    assert_raise_with_message(ArgumentError, /block accepted/) {obj.f {}}
+    assert_raise_with_message(ArgumentError, /block accepted/) {obj.f(&proc {})}
+  end
+
+  def test_no_block_argument_in_block
+    assert_valid_syntax("proc do |&nil| end")
+    assert_valid_syntax("proc do |a, &nil| end")
+    assert_valid_syntax("proc do |*rest, &nil| end")
+    assert_valid_syntax("proc do |*rest, p, &nil| end")
+    assert_valid_syntax("proc do |a, *rest, &nil| end")
+    assert_valid_syntax("proc do |a, *rest, p, &nil| end")
+    assert_valid_syntax("proc do |a, k: nil, &nil| end")
+    assert_valid_syntax("proc do |a, k: nil, **kw, &nil| end")
+    assert_valid_syntax("proc do |a, *rest, k: nil, &nil| end")
+    assert_valid_syntax("proc do |a, *rest, k: nil, **kw, &nil| end")
+    assert_valid_syntax("proc do |a, *rest, p, k: nil, &nil| end")
+    assert_valid_syntax("proc do |a, *rest, p, k: nil, **kw, &nil| end")
+
+    pr = eval "proc {|&nil|}"
+    assert_nil(pr.call)
+    assert_raise_with_message(ArgumentError, /block accepted/) {pr.call {}}
+    pr = eval "proc {|a, &nil| a}"
+    assert_nil(pr.call)
+    assert_equal(1, pr.call(1))
+    assert_raise_with_message(ArgumentError, /block accepted/) {pr.call {}}
+  end
+
   def test_newline_in_block_parameters
     bug = '[ruby-dev:45292]'
     ["", "a", "a, b"].product(["", ";x", [";", "x"]]) do |params|