Fix all 'assigned but unused variable' warnings

- The variables in content_location_parser appear to have been copied
  from content_disposition_parser but are unused
- Ragel seems to always generate a useless testEof variable. The `if
  false` trick is also used in whitequark/parser@21581a2 to suppress the
  warning. As mentioned in the parser commit, `if false` will not
  actually generate instructions and so it has no runtime cost.

Co-authored-by: Guilherme Quirino <guilhermequirino74@gmail.com>

lib/mail/parsers/address_lists_parser.rb

@@ -33228,6 +33228,10 @@ def self.parse(data)
           end
         end
 
+        if false
+          testEof
+        end
+
         if p != eof || cs < 2461
           raise Mail::Field::IncompleteParseError.new(Mail::AddressList, data, p)
         end

lib/mail/parsers/address_lists_parser.rl

@@ -165,6 +165,10 @@ module Mail::Parsers
       %%write init;
       %%write exec;
 
+      if false
+        testEof
+      end
+
       if p != eof || cs < %%{ write first_final; }%%
         raise Mail::Field::IncompleteParseError.new(Mail::AddressList, data, p)
       end

lib/mail/parsers/content_disposition_parser.rb

@@ -887,6 +887,10 @@ def self.parse(data)
           end
         end
 
+        if false
+          testEof
+        end
+
         if p != eof || cs < 40
           raise Mail::Field::IncompleteParseError.new(Mail::ContentDispositionElement, data, p)
         end

lib/mail/parsers/content_disposition_parser.rl

@@ -75,6 +75,10 @@ module Mail::Parsers
       %%write init;
       %%write exec;
 
+      if false
+        testEof
+      end
+
       if p != eof || cs < %%{ write first_final; }%%
         raise Mail::Field::IncompleteParseError.new(Mail::ContentDispositionElement, data, p)
       end

lib/mail/parsers/content_location_parser.rb

@@ -588,7 +588,7 @@ def self.parse(data)
         return content_location if Mail::Utilities.blank?(data)
 
         # Parser state
-        disp_type_s = param_attr_s = param_attr = qstr_s = qstr = param_val_s = nil
+        qstr_s = qstr = param_val_s = nil
 
         # 5.1 Variables Used by Ragel
         p = 0
@@ -808,6 +808,10 @@ def self.parse(data)
           end
         end
 
+        if false
+          testEof
+        end
+
         if p != eof || cs < 32
           raise Mail::Field::IncompleteParseError.new(Mail::ContentLocationElement, data, p)
         end

lib/mail/parsers/content_location_parser.rl

@@ -54,7 +54,7 @@ module Mail::Parsers
       return content_location if Mail::Utilities.blank?(data)
 
       # Parser state
-      disp_type_s = param_attr_s = param_attr = qstr_s = qstr = param_val_s = nil
+      qstr_s = qstr = param_val_s = nil
 
       # 5.1 Variables Used by Ragel
       p = 0
@@ -64,6 +64,10 @@ module Mail::Parsers
       %%write init;
       %%write exec;
 
+      if false
+        testEof
+      end
+
       if p != eof || cs < %%{ write first_final; }%%
         raise Mail::Field::IncompleteParseError.new(Mail::ContentLocationElement, data, p)
       end

lib/mail/parsers/content_transfer_encoding_parser.rb

@@ -508,6 +508,10 @@ def self.parse(data)
           end
         end
 
+        if false
+          testEof
+        end
+
         if p != eof || cs < 21
           raise Mail::Field::IncompleteParseError.new(Mail::ContentTransferEncodingElement, data, p)
         end

lib/mail/parsers/content_transfer_encoding_parser.rl

@@ -57,6 +57,10 @@ module Mail::Parsers
       %%write init;
       %%write exec;
 
+      if false
+        testEof
+      end
+
       if p != eof || cs < %%{ write first_final; }%%
         raise Mail::Field::IncompleteParseError.new(Mail::ContentTransferEncodingElement, data, p)
       end

lib/mail/parsers/content_type_parser.rb

@@ -1034,6 +1034,10 @@ def self.parse(data)
           end
         end
 
+        if false
+          testEof
+        end
+
         if p != eof || cs < 47
           raise Mail::Field::IncompleteParseError.new(Mail::ContentTypeElement, data, p)
         end

lib/mail/parsers/content_type_parser.rl

@@ -76,6 +76,10 @@ module Mail::Parsers
       %%write init;
       %%write exec;
 
+      if false
+        testEof
+      end
+
       if p != eof || cs < %%{ write first_final; }%%
         raise Mail::Field::IncompleteParseError.new(Mail::ContentTypeElement, data, p)
       end

lib/mail/parsers/date_time_parser.rb

@@ -877,6 +877,10 @@ def self.parse(data)
           end
         end
 
+        if false
+          testEof
+        end
+
         if p != eof || cs < 103
           raise Mail::Field::IncompleteParseError.new(Mail::DateTimeElement, data, p)
         end

lib/mail/parsers/date_time_parser.rl

@@ -55,6 +55,10 @@ module Mail::Parsers
       %%write init;
       %%write exec;
 
+      if false
+        testEof
+      end
+
       if p != eof || cs < %%{ write first_final; }%%
         raise Mail::Field::IncompleteParseError.new(Mail::DateTimeElement, data, p)
       end

lib/mail/parsers/envelope_from_parser.rb

@@ -3661,6 +3661,10 @@ def self.parse(data)
           end
         end
 
+        if false
+          testEof
+        end
+
         if p != eof || cs < 257
           raise Mail::Field::IncompleteParseError.new(Mail::EnvelopeFromElement, data, p)
         end

lib/mail/parsers/envelope_from_parser.rl

@@ -75,6 +75,10 @@ module Mail::Parsers
       %%write init;
       %%write exec;
 
+      if false
+        testEof
+      end
+
       if p != eof || cs < %%{ write first_final; }%%
         raise Mail::Field::IncompleteParseError.new(Mail::EnvelopeFromElement, data, p)
       end

lib/mail/parsers/message_ids_parser.rb

@@ -5147,6 +5147,10 @@ def self.parse(data)
           end
         end
 
+        if false
+          testEof
+        end
+
         if p != eof || cs < 318
           raise Mail::Field::IncompleteParseError.new(Mail::MessageIdsElement, data, p)
         end

lib/mail/parsers/message_ids_parser.rl

@@ -79,6 +79,10 @@ module Mail::Parsers
       %%write init;
       %%write exec;
 
+      if false
+        testEof
+      end
+
       if p != eof || cs < %%{ write first_final; }%%
         raise Mail::Field::IncompleteParseError.new(Mail::MessageIdsElement, data, p)
       end

lib/mail/parsers/mime_version_parser.rb

@@ -499,6 +499,10 @@ def self.parse(data)
           end
         end
 
+        if false
+          testEof
+        end
+
         if p != eof || cs < 23
           raise Mail::Field::IncompleteParseError.new(Mail::MimeVersionElement, data, p)
         end

lib/mail/parsers/mime_version_parser.rl

@@ -54,6 +54,10 @@ module Mail::Parsers
       %%write init;
       %%write exec;
 
+      if false
+        testEof
+      end
+
       if p != eof || cs < %%{ write first_final; }%%
         raise Mail::Field::IncompleteParseError.new(Mail::MimeVersionElement, data, p)
       end

lib/mail/parsers/phrase_lists_parser.rb

@@ -870,6 +870,10 @@ def self.parse(data)
           end
         end
 
+        if false
+          testEof
+        end
+
         if p != eof || cs < 42
           raise Mail::Field::IncompleteParseError.new(Mail::PhraseList, data, p)
         end

lib/mail/parsers/phrase_lists_parser.rl

@@ -76,6 +76,10 @@ module Mail::Parsers
       %%write init;
       %%write exec;
 
+      if false
+        testEof
+      end
+
       if p != eof || cs < %%{ write first_final; }%%
         raise Mail::Field::IncompleteParseError.new(Mail::PhraseList, data, p)
       end

lib/mail/parsers/received_parser.rb

@@ -8768,6 +8768,10 @@ def self.parse(data)
           end
         end
 
+        if false
+          testEof
+        end
+
         if p != eof || cs < 648
           raise Mail::Field::IncompleteParseError.new(Mail::ReceivedElement, data, p)
         end

lib/mail/parsers/received_parser.rl

@@ -77,6 +77,10 @@ module Mail::Parsers
       %%write init;
       %%write exec;
 
+      if false
+        testEof
+      end
+
       if p != eof || cs < %%{ write first_final; }%%
         raise Mail::Field::IncompleteParseError.new(Mail::ReceivedElement, data, p)
       end

spec/mail/network/delivery_methods/smtp_connection_spec.rb

@@ -16,8 +16,6 @@
   end
 
   it "should not dot-stuff unterminated last line with no leading dot" do
-    body = "this is a test\n.\nonly a test"
-
     Mail.deliver do
       from 'from@example.com'
       to 'to@example.com'