（Dart） Reference providers can only match DartStringLiteralExpression

IntelliJ Platform
1 
class L10nReferenceContributor : PsiReferenceContributor() {
    override fun registerReferenceProviders(p0: PsiReferenceRegistrar) {
        p0.registerReferenceProvider(
            PlatformPatterns.psiElement(), L10nReferenceProvider(), PsiReferenceRegistrar.HIGHER_PRIORITY
        )
    }
}
internal class L10nReferenceProvider() : PsiReferenceProvider() {
    override fun getReferencesByElement(
        p0: PsiElement,
        p1: ProcessingContext
    ): Array<out PsiReference?> {
        println("${p0}")  // only print dart string type psi element
        return PsiReference.EMPTY_ARRAY
    }
}