[ruby/irb] Move IRB::TOPLEVEL_BINDING from exe/irb to lib/irb/workspace.rb

https://github.com/ruby/irb/commit/e736a77076

lib/irb.rb

@@ -669,6 +669,8 @@ module IRB
           lines = lines.reverse if order == :bottom
           lines.map{ |l| l + "\n" }.join
         }
+        # The "<top (required)>" in "(irb)" may be the top level of IRB so imitate the main object.
+        message = message.gsub(/\(irb\):(?<num>\d+):in `<(?<frame>top \(required\))>'/)  { "(irb):#{$~[:num]}:in `<main>'" }
         puts message
       end
       print "Maybe IRB bug!\n" if irb_bug

lib/irb/workspace.rb

@@ -12,6 +12,7 @@
 
 require "delegate"
 
+IRB::TOPLEVEL_BINDING = binding
 module IRB # :nodoc:
   class WorkSpace
     # Creates a new workspace.
@@ -57,7 +58,7 @@ EOF
                           __FILE__,
                           __LINE__ - 3)
         when 4  # binding is a copy of TOPLEVEL_BINDING (default)
-          # Note that this will typically be IRB::TOPLEVEL_BINDING (see exe/irb)
+          # Note that this will typically be IRB::TOPLEVEL_BINDING
           # This is to avoid RubyGems' local variables (see issue #17623)
           @binding = TOPLEVEL_BINDING.dup
         end

libexec/irb

@@ -8,5 +8,4 @@
 
 require "irb"
 
-IRB::TOPLEVEL_BINDING = binding
 IRB.start(__FILE__)