Ruby: Fix bug in implicitAssignmentNode

[hvitved]

A small bug fix where in cases like

class RescueSetter
  def name
    @name
  end

  def name=(value)
    @name = value
  end

  def foo(msg)
    raise msg
  rescue => self.name # calls `name=`
    :caught
  end
end

self.name was incorrectly marked as updating variables named self and name, instead of calling the name= setter.

DCA confirms that we remove some rb/useless-assignment-to-local FPs.

[Copilot]

Pull request overview

Fixes Ruby variable-scope/namebinding for the rescue ... => <target> exception-variable assignment when the target is a setter-like expression (e.g. self.name), avoiding incorrectly treating sub-expressions as implicit variable writes and reducing rb/useless-assignment-to-local false positives.

Changes:

• Refines implicit/explicit assignment ancestor traversal in Variable.qll to only propagate through LHS-assignment container nodes.
• Adds a Ruby regression test (RescueSetter) covering rescue => self.name setter behavior.
• Updates variable/SSA/access expected outputs for the new test coverage and corrected binding.

Show a summary per file

File	Description
ruby/ql/lib/codeql/ruby/ast/internal/Variable.qll	Restricts recursive “inside assignment” detection to assignment-LHS container parents to avoid misclassifying setter targets.
ruby/ql/test/library-tests/variables/scopes.rb	Adds RescueSetter demonstrating exception assignment to a setter-like target in rescue => ....
ruby/ql/test/library-tests/variables/varscopes.expected	Updates expected scope ranges to include the new test class/methods.
ruby/ql/test/library-tests/variables/variable.expected	Updates expected variable entries/scopes reflecting corrected implicit assignment behavior.
ruby/ql/test/library-tests/variables/varaccess.expected	Updates expected variable access/write classifications for the new scenario.
ruby/ql/test/library-tests/variables/ssa.expected	Updates expected SSA definitions/reads to match the corrected binding and new test code.
ruby/ql/test/library-tests/variables/parameter.expected	Adds expected parameter-variable entries for value and msg from the new test methods.

Copilot's findings

• Files reviewed: 7/7 changed files
• Comments generated: 0