Issue #10929 has been updated by Seiei Higa.

File block_from_nil.patch added

I wrote a patch for this issue.

```diff
diff --git bootstraptest/test_block.rb bootstraptest/test_block.rb
index cdc5960..4347fdd 100644
--- bootstraptest/test_block.rb
+++ bootstraptest/test_block.rb
@@ -611,3 +611,17 @@ assert_equal 'ok', %q{
   end
   'ok'
 }
+
+assert_equal 'ok', %q{
+  class NilClass
+    def to_proc
+      Proc.new {|x| x }
+    end
+  end
+
+  def foo(&blk)
+    blk.call('ok')
+  end
+
+  foo(&nil)
+}, '[ruby-core:68384] [Bug #10929]'
diff --git vm_args.c vm_args.c
index cf7256b..e1cb8ac 100644
--- vm_args.c
+++ vm_args.c
@@ -755,7 +755,7 @@ vm_caller_setup_arg_block(const rb_thread_t *th, rb_control_frame_t *reg_cfp, rb

 	proc = *(--reg_cfp->sp);

-	if (proc != Qnil) {
+	if (proc != Qnil || rb_respond_to(Qnil, idTo_proc)) {
 	    if (!rb_obj_is_proc(proc)) {
 		VALUE b;
```

----------------------------------------
Bug #10929: NilClass#to_proc and & don't mix?
https://bugs.ruby-lang.org/issues/10929#change-51787

* Author: Thomas Sawyer
* Status: Open
* Priority: Low
* Assignee: 
* ruby -v: ruby 2.0.0p247 (2013-06-27 revision 41674) [x86_64-linux]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
----------------------------------------
This is sort of like a "who would ever care" kind of bug. Nonetheless technically it seems like it is one. So I thought it best that I report it just the same.

~~~
  class NilClass
    def to_proc
      Proc.new{ |*x| nil }
    end
  end

  def f(&b)
    b.call(1)
  end  

  f(&nil)
  => NoMethodError: undefined method `call' for nil:NilClass
~~~

(Maybe it was fixed already. Filing out this issue reminded me I need to update my version of Ruby.)

---Files--------------------------------
block_from_nil.patch (771 Bytes)


-- 
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