Drop Proc#bind

Proc responds to `instance_exec` since forever ago
Official Ruby docs only go back to 2.0, so I added that as the minimum version,
if someone should for some reason still use rubies before that.

https://docs.ruby-lang.org/en/2.0.0/BasicObject.html#method-i-instance_exec

Author: Earlopain

.rubocop_todo.yml

@@ -196,14 +196,6 @@ Rails/RefuteMethods:
   Exclude:
     - 'test/shoulda/helpers_test.rb'
 
-# Offense count: 1
-# Cop supports --auto-correct.
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: strict, flexible
-Rails/TimeZone:
-  Exclude:
-    - 'lib/shoulda/context/proc_extensions.rb'
-
 # Offense count: 2
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle.
@@ -267,7 +259,6 @@ Style/MutableConstant:
 # Cop supports --auto-correct.
 Style/ParallelAssignment:
   Exclude:
-    - 'lib/shoulda/context/proc_extensions.rb'
     - 'test/shoulda/should_test.rb'
 
 # Offense count: 1

lib/shoulda/context.rb

@@ -2,7 +2,6 @@
 require "shoulda/context/configuration"
 require "shoulda/context/context"
 require "shoulda/context/dsl"
-require "shoulda/context/proc_extensions"
 require "shoulda/context/test_framework_detection"
 require "shoulda/context/version"
 require "shoulda/context/world"

lib/shoulda/context/context.rb

@@ -36,12 +36,7 @@ def initialize(name, parent, &blk)
       end
 
       def merge_block(&blk)
-        if self.respond_to?(:instance_exec)
-          self.instance_exec(&blk)
-        else
-          # deprecated in Rails 4.x
-          blk.bind(self).call
-        end
+        self.instance_exec(&blk)
       end
 
       def context(name, &blk)
@@ -170,23 +165,13 @@ def run_parent_setup_blocks(binding)
 
       def run_current_setup_blocks(binding)
         setup_blocks.each do |setup_block|
-          if binding.respond_to?(:instance_exec)
-            binding.instance_exec(&setup_block)
-          else
-            # deprecated in Rails 4.x
-            setup_block.bind(binding).call
-          end
+          binding.instance_exec(&setup_block)
         end
       end
 
       def run_all_teardown_blocks(binding)
         teardown_blocks.reverse.each do |teardown_block|
-          if binding.respond_to?(:instance_exec)
-            binding.instance_exec(&teardown_block)
-          else
-            # deprecated in Rails 4.x
-            teardown_block.bind(binding).call
-          end
+          binding.instance_exec(&teardown_block)
         end
         self.parent.run_all_teardown_blocks(binding) if am_subcontext?
       end

lib/shoulda/context/proc_extensions.rb

@@ -15,6 +15,8 @@ Gem::Specification.new do |s|
   s.description = "Context framework extracted from Shoulda"
   s.license     = "MIT"
 
+  s.required_ruby_version = ">= 2.0.0"
+
   s.files            = `git ls-files`.split("\n")
   s.test_files       = `git ls-files -- {test,spec,features}/*`.split("\n")
   s.executables      = `git ls-files -- exe/*`.split("\n").map { |f| File.basename(f) }