diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 31962cf4..0730a6d1 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -6,50 +6,6 @@
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 1
-Lint/HandleExceptions:
-  Exclude:
-    - 'test/adapters/rack_test.rb'
-
-# Offense count: 1
-Lint/ReturnInVoidContext:
-  Exclude:
-    - 'lib/faraday/options/env.rb'
-
-# Offense count: 2
-# Cop supports --auto-correct.
-Lint/UnneededRequireStatement:
-  Exclude:
-    - 'lib/faraday.rb'
-    - 'lib/faraday/utils.rb'
-
-# Offense count: 6
-# Cop supports --auto-correct.
-# Configuration parameters: IgnoreEmptyBlocks, AllowUnusedKeywordArguments.
-Lint/UnusedBlockArgument:
-  Exclude:
-    - 'lib/faraday/encoders/nested_params_encoder.rb'
-    - 'lib/faraday/request/retry.rb'
-    - 'spec/faraday/options/options_spec.rb'
-    - 'test/adapters/test_middleware_test.rb'
-
-# Offense count: 5
-# Cop supports --auto-correct.
-# Configuration parameters: AllowUnusedKeywordArguments, IgnoreEmptyMethods.
-Lint/UnusedMethodArgument:
-  Exclude:
-    - 'lib/faraday/adapter.rb'
-    - 'lib/faraday/adapter/em_http.rb'
-    - 'lib/faraday/adapter/em_synchrony.rb'
-    - 'script/generate_certs'
-    - 'spec/faraday/response/middleware_spec.rb'
-
-# Offense count: 1
-# Configuration parameters: CheckForMethodsWithNoSideEffects.
-Lint/Void:
-  Exclude:
-    - 'lib/faraday/connection.rb'
-
 # Offense count: 41
 Metrics/AbcSize:
   Max: 86
@@ -63,7 +19,7 @@ Metrics/BlockLength:
 # Offense count: 5
 # Configuration parameters: CountComments.
 Metrics/ClassLength:
-  Max: 217
+  Max: 216
 
 # Offense count: 20
 Metrics/CyclomaticComplexity:
diff --git a/lib/faraday.rb b/lib/faraday.rb
index 520dd3c7..1b1d9727 100644
--- a/lib/faraday.rb
+++ b/lib/faraday.rb
@@ -1,6 +1,5 @@
 # frozen_string_literal: true
 
-require 'thread'
 require 'cgi'
 require 'set'
 require 'forwardable'
diff --git a/lib/faraday/adapter.rb b/lib/faraday/adapter.rb
index 36831153..12bc303f 100644
--- a/lib/faraday/adapter.rb
+++ b/lib/faraday/adapter.rb
@@ -35,7 +35,7 @@ module Faraday
     extend Parallelism
     self.supports_parallel = false
 
-    def initialize(app = nil, opts = {}, &block)
+    def initialize(_app = nil, opts = {}, &block)
       @app = lambda { |env| env.response }
       @connection_options = opts
       @config_block = block
diff --git a/lib/faraday/adapter/em_http.rb b/lib/faraday/adapter/em_http.rb
index ad8d8083..cdc65fab 100644
--- a/lib/faraday/adapter/em_http.rb
+++ b/lib/faraday/adapter/em_http.rb
@@ -90,7 +90,7 @@ module Faraday
       self.supports_parallel = true
 
       # @return [Manager]
-      def self.setup_parallel_manager(options = nil)
+      def self.setup_parallel_manager(_options = nil)
         Manager.new
       end
 
diff --git a/lib/faraday/adapter/em_synchrony.rb b/lib/faraday/adapter/em_synchrony.rb
index 4838eeb1..e9ca56ab 100644
--- a/lib/faraday/adapter/em_synchrony.rb
+++ b/lib/faraday/adapter/em_synchrony.rb
@@ -17,7 +17,7 @@ module Faraday
       self.supports_parallel = true
 
       # @return [ParallelManager]
-      def self.setup_parallel_manager(options = {})
+      def self.setup_parallel_manager(_options = nil)
         ParallelManager.new
       end
 
diff --git a/lib/faraday/connection.rb b/lib/faraday/connection.rb
index 9f662402..6a450a68 100644
--- a/lib/faraday/connection.rb
+++ b/lib/faraday/connection.rb
@@ -403,8 +403,6 @@ module Faraday
     #   conn.path_prefix # => "/api"
     #
     #   conn.get("nigiri?page=2") # accesses https://sushi.com/api/nigiri
-    #
-    # @return [URI] the parsed URI from the given input
     def url_prefix=(url, encoder = nil)
       uri = @url_prefix = Utils.URI(url)
       self.path_prefix = uri.path
@@ -416,8 +414,6 @@ module Faraday
         basic_auth user, password
         uri.user = uri.password = nil
       end
-
-      uri
     end
 
     # Sets the path prefix and ensures that it always has a leading
diff --git a/lib/faraday/encoders/nested_params_encoder.rb b/lib/faraday/encoders/nested_params_encoder.rb
index ea2fcca1..313fb3f0 100644
--- a/lib/faraday/encoders/nested_params_encoder.rb
+++ b/lib/faraday/encoders/nested_params_encoder.rb
@@ -52,7 +52,7 @@ module Faraday
           return new_parent if value.empty?
 
           buffer = +''
-          value.each_with_index do |val, i|
+          value.each do |val|
             buffer << "#{to_query.call(new_parent, val)}&"
           end
           return buffer.chop
diff --git a/lib/faraday/options/env.rb b/lib/faraday/options/env.rb
index b2c71a10..9a201403 100644
--- a/lib/faraday/options/env.rb
+++ b/lib/faraday/options/env.rb
@@ -92,7 +92,10 @@ module Faraday
     # @param key [Object]
     # @param value [Object]
     def []=(key, value)
-      return super(current_body, value) if key == :body
+      if key == :body
+        super(current_body, value)
+        return
+      end
 
       if in_member_set?(key)
         super(key, value)
diff --git a/lib/faraday/request/retry.rb b/lib/faraday/request/retry.rb
index a9fcab10..3ab0beb0 100644
--- a/lib/faraday/request/retry.rb
+++ b/lib/faraday/request/retry.rb
@@ -29,7 +29,7 @@ module Faraday
                                          :backoff_factor, :exceptions, :methods, :retry_if, :retry_block,
                                          :retry_statuses)
 
-      DEFAULT_CHECK = lambda { |env, exception| false }
+      DEFAULT_CHECK = lambda { |_env, _exception| false }
 
       def self.from(value)
         if Integer === value
diff --git a/lib/faraday/utils.rb b/lib/faraday/utils.rb
index 415f795e..221b2242 100644
--- a/lib/faraday/utils.rb
+++ b/lib/faraday/utils.rb
@@ -1,7 +1,5 @@
 # frozen_string_literal: true
 
-require 'thread'
-
 require 'faraday/utils/headers'
 require 'faraday/utils/params_hash'
 
diff --git a/script/generate_certs b/script/generate_certs
index e9379c13..538b9065 100755
--- a/script/generate_certs
+++ b/script/generate_certs
@@ -11,7 +11,7 @@ $shell = ARGV.include? '-s'
 
 # Adapted from WEBrick::Utils. Skips cert extensions so it
 # can be used as a CA bundle
-def create_self_signed_cert(bits, cname, comment)
+def create_self_signed_cert(bits, cname, _comment)
   rsa = OpenSSL::PKey::RSA.new(bits)
   cert = OpenSSL::X509::Certificate.new
   cert.version = 2
diff --git a/spec/faraday/options/options_spec.rb b/spec/faraday/options/options_spec.rb
index 79d6b55f..a9d73199 100644
--- a/spec/faraday/options/options_spec.rb
+++ b/spec/faraday/options/options_spec.rb
@@ -255,7 +255,7 @@ RSpec.describe Faraday::Options do
 
       context 'when the fetched key has no value' do
         it 'uses falsey default' do
-          expect(subject.fetch(:sub_a, false) { |k| :blah }).to be_falsey
+          expect(subject.fetch(:sub_a, false) { |_| :blah }).to be_falsey
         end
 
         it 'accepts block' do
@@ -273,7 +273,7 @@ RSpec.describe Faraday::Options do
         end
 
         it 'grabs value' do
-          expect(subject.fetch(:sub_a, false) { |k| :blah }).to eq(1)
+          expect(subject.fetch(:sub_a, false) { |_| :blah }).to eq(1)
         end
 
         it 'works with key' do
diff --git a/spec/faraday/response/middleware_spec.rb b/spec/faraday/response/middleware_spec.rb
index e5b18f5f..3c3adf27 100644
--- a/spec/faraday/response/middleware_spec.rb
+++ b/spec/faraday/response/middleware_spec.rb
@@ -29,7 +29,7 @@ RSpec.describe Faraday::Response::Middleware do
   context 'with a custom ResponseMiddleware but empty response' do
     let(:custom_middleware) do
       Class.new(Faraday::Response::Middleware) do
-        def parse(body)
+        def parse(_body)
           raise 'this should not be called'
         end
       end
diff --git a/test/adapters/rack_test.rb b/test/adapters/rack_test.rb
index 44cd11d3..1204f91c 100644
--- a/test/adapters/rack_test.rb
+++ b/test/adapters/rack_test.rb
@@ -28,7 +28,7 @@ module Adapters
       conn = create_connection(request: { timeout: 1, open_timeout: 1 })
       begin
         conn.get '/slow'
-      rescue Faraday::ClientError
+      rescue Faraday::ClientError # rubocop:disable Lint/HandleExceptions
       end
     end
 
diff --git a/test/adapters/test_middleware_test.rb b/test/adapters/test_middleware_test.rb
index dbc07500..5b0ff8b3 100644
--- a/test/adapters/test_middleware_test.rb
+++ b/test/adapters/test_middleware_test.rb
@@ -16,7 +16,7 @@ module Adapters
         stub.get(/\A\/resources\/\d+(?:\?|\z)/) do
           [200, { 'Content-Type' => 'text/html' }, 'show']
         end
-        stub.get(/\A\/resources\/(specified)\z/) do |env, meta|
+        stub.get(/\A\/resources\/(specified)\z/) do |_env, meta|
           [200, { 'Content-Type' => 'text/html' }, "show #{meta[:match_data][1]}"]
         end
         stub.get('http://domain.test/hello') do