Error processing request on document highlight

[apiology]

While hovering over the first . in the following:

ActiveRecord::Schema[8.0].define(version: 2025_09_24_130126) do
  create_table "products", force: :cascade do |t|
    t.string "name"
    t.string "part_number"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end
end

receive:

[WARN] Error processing request: [NoMethodError] undefined method '+' for nil
[WARN] /Users/broz/src/solargraph/lib/solargraph/parser/parser_gem/class_methods.rb:58:in 'block in Solargraph::Parser::ParserGem::ClassMethods#references'
/Users/broz/src/solargraph/lib/solargraph/parser/parser_gem/class_methods.rb:63:in 'block in Solargraph::Parser::ParserGem::ClassMethods#references'
/Users/broz/src/solargraph/lib/solargraph/parser/parser_gem/class_methods.rb:60:in 'Array#map'
/Users/broz/src/solargraph/lib/solargraph/parser/parser_gem/class_methods.rb:60:in 'Solargraph::Parser::ParserGem::ClassMethods#references'
/Users/broz/src/solargraph/lib/solargraph/source.rb:172:in 'Solargraph::Source#references'
/Users/broz/src/solargraph/lib/solargraph/source_map.rb:134:in 'Solargraph::SourceMap#references'
/Users/broz/src/solargraph/lib/solargraph/library.rb:256:in 'block in Solargraph::Library#references_from'
/Users/broz/src/solargraph/lib/solargraph/library.rb:255:in 'Array#each'
/Users/broz/src/solargraph/lib/solargraph/library.rb:255:in 'Solargraph::Library#references_from'
/Users/broz/src/solargraph/lib/solargraph/language_server/host.rb:583:in 'Solargraph::LanguageServer::Host#references_from'
/Users/broz/src/solargraph/lib/solargraph/language_server/message/text_document/document_highlight.rb:6:in 'Solargraph::LanguageServer::Message::TextDocument::DocumentHighlight#process'
/Users/broz/src/solargraph/lib/solargraph/language_server/host.rb:104:in 'Solargraph::LanguageServer::Host#receive'
/Users/broz/src/solargraph/lib/solargraph/language_server/host/message_worker.rb:69:in 'Solargraph::LanguageServer::Host::MessageWorker#tick'
/Users/broz/src/solargraph/lib/solargraph/language_server/host/message_worker.rb:59:in 'block in Solargraph::LanguageServer::Host::MessageWorker#start'

To reproduce:

gem install rails -v 8.0.3
rails _8.0.3_ new rails8
cd rails8
# add solargraph and solargraph-rails
bundle install
bundle exec solargraph config
# add solargraph-rails to config
bin/rails generate migration CreateProducts name:string part_number:string # create table
rails db:create
rails db:migrate
# hover over first `.` in db/schema.rb

[apiology]

Probably an existing issue; only encountered it as I was trying to get a new thing to work right.