Fix a case where numbered parameters should not be allowed

Because `proc{|| @1}` is a syntax error, the following should
also be syntax errors:

```ruby
proc { |
| @1}
```

```ruby
proc { |; a| @1 }
```

This fixes both cases.

[Bug #15825]

2 files changed, 3 insertions, 0 deletions

diff --git a/parse.y b/parse.y
index af425133c9..de64746159 100644
--- a/parse.y
+++ b/parse.y
@@ -3307,6 +3307,7 @@ opt_block_param	: none
 block_param_def	: '|' opt_bv_decl '|'
 		    {
 			p->cur_arg = 0;
+			p->max_numparam = -1;
 		    /*%%%*/
 			$$ = 0;
 		    /*% %*/
diff --git a/test/ruby/test_syntax.rb b/test/ruby/test_syntax.rb
index ff8c62f6a1..f2df65fb6c 100644
--- a/test/ruby/test_syntax.rb
+++ b/test/ruby/test_syntax.rb
@@ -1313,6 +1313,8 @@ eom
     assert_equal("12", eval('[1,2].then {"#@1#@2"}'))
     assert_equal(3, eval('->{@1+@2}.call(1,2)'))
     assert_syntax_error('proc {|| @1}', /ordinary parameter is defined/)
+    assert_syntax_error('proc {|;a| @1}', /ordinary parameter is defined/)
+    assert_syntax_error("proc {|\n| @1}", /ordinary parameter is defined/)
     assert_syntax_error('proc {|x| @1}', /ordinary parameter is defined/)
     assert_syntax_error('->(){@1}', /ordinary parameter is defined/)
     assert_syntax_error('->(x){@1}', /ordinary parameter is defined/)