Prevent "assigned but unused variable" warnings

test/ruby/test_call.rb

@@ -133,6 +133,9 @@ class TestCall < Test::Unit::TestCase
     kw = {}
     b = lambda{}
 
+    # Prevent "assigned but unused variable" warnings
+    _ = [h, a, kw, b]
+
     message = /keyword arg given in index/
 
     # +=, without block, non-popped
@@ -294,6 +297,9 @@ class TestCall < Test::Unit::TestCase
     a = []
     kw = {}
 
+    # Prevent "assigned but unused variable" warnings
+    _ = [h, a, kw]
+
     assert_syntax_error(%q{h[*a, 2, b: 5, **kw] += 1}, message)
   end
 

test/ruby/test_parse.rb

@@ -498,6 +498,10 @@ class TestParse < Test::Unit::TestCase
     t = Object.new
     a = []
     blk = proc {|x| a << x }
+
+    # Prevent an "assigned but unused variable" warning
+    _ = blk
+
     def t.[](_)
       yield(:aref)
       nil