Bonds are a great indicator of growth expectations. Stocks are as well, but stocks get a lot of attention in that regard while bonds get a lot less attention in general, and also, a lot less attention as growth indicators. However, the bond market is gigantically large, swamping the stock market in size. So, if you believe in the 'wisdom of crowds', bonds are a bigger crowd and probably right. Plus, bonds get less attention from do-it-yourself day traders, which make bonds likely to be somewhat more influenced by professionals.
There are two things to notice in the following chart: the rise of treasuries and the collapse of high yields in relative return ranking from the first three quarters of 2018 to the 4th quarter. They are both growth sensitive, but in opposite ways -- treasuries like low growth environments and high yields like high growth environments. The drop in the relative performance of high yields and the rise in treasuries both signal a shift in market-implied growth expectations.
*Data source: FactSet; Chart source: Bowyer Research
Bonds, as well as stocks and commodities, all sent the same strong signal at the end of the quarter which just ended: they say that growth is slowing down.