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 <[email protected]>

Author: skipkayhil

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