class TypeProf::Core::AST::SigFuncType::SigTyBaseNilNode

# File bundled-src/typeprof-0.31.1/lib/typeprof/core/ast/sig_type.rb, line 200
def contravariant_vertex0(genv, changes, vtx, subst)
  changes.add_edge(genv, Source.new(genv.nil_type), vtx)
end

# File bundled-src/typeprof-0.31.1/lib/typeprof/core/ast/sig_type.rb, line 196
def covariant_vertex0(genv, changes, vtx, subst)
  changes.add_edge(genv, Source.new(genv.nil_type), vtx)
end

# File bundled-src/typeprof-0.31.1/lib/typeprof/core/ast/sig_type.rb, line 212
def show
  "nil"
end

# File bundled-src/typeprof-0.31.1/lib/typeprof/core/ast/sig_type.rb, line 204
def typecheck(genv, changes, vtx, subst)
  changes.add_edge(genv, vtx, changes.target)
  vtx.each_type do |ty|
    return false unless ty == genv.nil_type
  end
  true
end