class ViewComponent::Compiler

def template_errors: () -> untyped

def template_errors
  @__vc_template_errors ||=
    begin
      errors = []
      if (templates + inline_calls).empty? && !has_inline_template?
        errors << "Couldn't find a template file or inline render method for #{component_class}."
      end
      if templates.count { |template| template[:variant].nil? } > 1
        errors <<
          "More than one template found for #{component_class}. " \
          "There can only be one default template file per component."
      end
      invalid_variants =
        templates
          .group_by { |template| template[:variant] }
          .map { |variant, grouped| variant if grouped.length > 1 }
          .compact
          .sort
      unless invalid_variants.empty?
        errors <<
          "More than one template found for #{"variant".pluralize(invalid_variants.count)} " \
          "#{invalid_variants.map { |v| "'#{v}'" }.to_sentence} in #{component_class}. " \
          "There can only be one template file per variant."
      end
      if templates.find { |template| template[:variant].nil? } && inline_calls_defined_on_self.include?(:call)
        errors <<
          "Template file and inline render method found for #{component_class}. " \
          "There can only be a template file or inline render method per component."
      end
      duplicate_template_file_and_inline_variant_calls =
        templates.pluck(:variant) & variants_from_inline_calls(inline_calls_defined_on_self)
      unless duplicate_template_file_and_inline_variant_calls.empty?
        count = duplicate_template_file_and_inline_variant_calls.count
        errors <<
          "Template #{"file".pluralize(count)} and inline render #{"method".pluralize(count)} " \
          "found for #{"variant".pluralize(count)} " \
          "#{duplicate_template_file_and_inline_variant_calls.map { |v| "'#{v}'" }.to_sentence} " \
          "in #{component_class}. " \
          "There can only be a template file or inline render method per variant."
      end
      uniq_variants = variants.compact.uniq
      normalized_variants = uniq_variants.map { |variant| normalized_variant_name(variant) }
      colliding_variants = uniq_variants.select do |variant|
        normalized_variants.count(normalized_variant_name(variant)) > 1
      end
      unless colliding_variants.empty?
        errors <<
          "Colliding templates #{colliding_variants.sort.map { |v| "'#{v}'" }.to_sentence} " \
          "found in #{component_class}."
      end
      errors
    end
end