createFirAnonymousFunction
inline fun FirSession.createFirAnonymousFunction(origin: FirDeclarationOrigin, returnTypeRef: FirTypeRef, symbol: FirAnonymousFunctionSymbol = FirAnonymousFunctionSymbol(), isLambda: Boolean = false, hasExplicitParameterList: Boolean = false, builder: FirAnonymousFunctionBuilder.() -> Unit = {}): FirAnonymousFunction