diff --git a/mrblib/numeric.rb b/mrblib/numeric.rb
index 67e76ece2..a047f019c 100644
--- a/mrblib/numeric.rb
+++ b/mrblib/numeric.rb
@@ -69,7 +69,7 @@ class Integer
   # Calls the given block +self+ times.
   #
   # ISO 15.2.8.3.22
-  def times &block
+  def times(&block)
     return to_enum :times unless block
 
     i = 0
diff --git a/test/t/bs_block.rb b/test/t/bs_block.rb
index c37d1b538..08580d58a 100644
--- a/test/t/bs_block.rb
+++ b/test/t/bs_block.rb
@@ -313,7 +313,7 @@ assert('BS Block 25') do
 end
 
 assert('BS Block 26') do
-  def m a
+  def m(a)
     yield a
   end
   assert_equal(2) do
diff --git a/test/t/class.rb b/test/t/class.rb
index 1b4b84890..f4d99318a 100644
--- a/test/t/class.rb
+++ b/test/t/class.rb
@@ -40,7 +40,7 @@ assert('Class#new', '15.2.3.3.3') do
   end
 
   class TestClass
-    def initialize args, &block
+    def initialize(args, &block)
       @result = if not args.nil? and block.nil?
         # only arguments
         :only_args
diff --git a/test/t/float.rb b/test/t/float.rb
index e4c25b34e..1a7f6c99a 100644
--- a/test/t/float.rb
+++ b/test/t/float.rb
@@ -216,7 +216,7 @@ assert('Float#truncate', '15.2.9.3.15') do
 end
 
 assert('Float#divmod') do
-  def check_floats exp, act
+  def check_floats(exp, act)
     assert_float exp[0], act[0]
     assert_float exp[1], act[1]
   end