Allow parenthesed do-block in cmdarg

Flush cmdarg flags inside left-paren in a command argument, to allow
parenthesed `do-block` as an argument without arguments parentheses.
`CMDARG_PUSH(0)` for tLPAREN_ARG is before `CMDARG_PUSH(1)` in
`command_args` due to look-ahead.

1 files changed, 11 insertions, 0 deletions

diff --git a/test/t/syntax.rb b/test/t/syntax.rb
index fac73aa7b..d761b1991 100644
--- a/test/t/syntax.rb
+++ b/test/t/syntax.rb
@@ -254,3 +254,14 @@ assert('External command execution.') do
   end
   true
 end
+
+assert('parenthesed do-block in cmdarg') do
+  class ParenDoBlockCmdArg
+    def test(block)
+      block.call
+    end
+  end
+  x = ParenDoBlockCmdArg.new
+  result = x.test (proc do :ok; end)
+  assert_equal :ok, result
+end