Suppress warnings except for when last evaluation

Co-authored-by: Kazuhiro NISHIYAMA <zn@mbf.nifty.com>

lib/irb.rb

@@ -766,7 +766,10 @@ module IRB
       # s-expression where the second selement of the top level array is an
       # array of parsed expressions. The first element of each expression is the
       # expression's type.
-      ASSIGNMENT_NODE_TYPES.include?(Ripper.sexp(line)&.dig(1,-1,0))
+      verbose, $VERBOSE = $VERBOSE, nil
+      result = ASSIGNMENT_NODE_TYPES.include?(Ripper.sexp(line)&.dig(1,-1,0))
+      $VERBOSE = verbose
+      result
     end
 
     ATTR_TTY = "\e[%sm"

lib/irb/color.rb

@@ -154,6 +154,7 @@ module IRB # :nodoc:
       def scan(code, allow_last_error:)
         pos = [1, 0]
 
+        verbose, $VERBOSE = $VERBOSE, nil
         lexer = Ripper::Lexer.new(code)
         if lexer.respond_to?(:scan) # Ruby 2.7+
           lexer.scan.each do |elem|
@@ -177,6 +178,7 @@ module IRB # :nodoc:
             yield(elem.event, elem.tok, elem.state)
           end
         end
+        $VERBOSE = verbose
       end
 
       def dispatch_seq(token, expr, str, in_symbol:)

lib/irb/ruby-lex.rb

@@ -71,20 +71,27 @@ class RubyLex
     end
   end
 
+  def ripper_lex_without_warning(code)
+    verbose, $VERBOSE = $VERBOSE, nil
+    tokens = Ripper.lex(code)
+    $VERBOSE = verbose
+    tokens
+  end
+
   def set_auto_indent(context)
     if @io.respond_to?(:auto_indent) and context.auto_indent_mode
       @io.auto_indent do |lines, line_index, byte_pointer, is_newline|
         if is_newline
           md = lines[line_index - 1].match(/(\A +)/)
           prev_spaces = md.nil? ? 0 : md[1].count(' ')
-          @tokens = Ripper.lex(lines[0..line_index].join("\n"))
+          @tokens = ripper_lex_without_warning(lines[0..line_index].join("\n"))
           depth_difference = check_newline_depth_difference
           prev_spaces + depth_difference * 2
         else
           code = line_index.zero? ? '' : lines[0..(line_index - 1)].map{ |l| l + "\n" }.join
           last_line = lines[line_index]&.byteslice(0, byte_pointer)
           code += last_line if last_line
-          @tokens = Ripper.lex(code)
+          @tokens = ripper_lex_without_warning(code)
           corresponding_token_depth = check_corresponding_token_depth
           if corresponding_token_depth
             corresponding_token_depth
@@ -97,7 +104,7 @@ class RubyLex
   end
 
   def check_state(code)
-    @tokens = Ripper.lex(code)
+    @tokens = ripper_lex_without_warning(code)
     ltype = process_literal_type
     indent = process_nesting_level
     continue = process_continue
@@ -160,7 +167,7 @@ class RubyLex
     end
     code = @line + (line.nil? ? '' : line)
     code.gsub!(/\s*\z/, '').concat("\n")
-    @tokens = Ripper.lex(code)
+    @tokens = ripper_lex_without_warning(code)
     @continue = process_continue
     @code_block_open = check_code_block(code)
     @indent = process_nesting_level

test/irb/test_context.rb

@@ -63,6 +63,12 @@ module TestIRB
       assert_not_match(/rescue _\.class/, e.message)
     end
 
+    def test_evaluate_with_onigmo_warning
+      assert_warning("(irb):1: warning: character class has duplicated range: /[aa]/\n") do
+        @context.evaluate('/[aa]/', 1)
+      end
+    end
+
     def test_eval_input
       verbose, $VERBOSE = $VERBOSE, nil
       input = TestInputMethod.new([