Concatenating nested classes using SASS [duplicate]
&
You can achieve this with the ampersand operator. Try:
.a .c
display: inline-block
&.date
width: 50px
The ampersand is a placeholder for parent selectors. And if you don't place a space after it in a nested selector it will output a concatenated selector (just what you want).
DEMO
Note: in deeper nested selectors & stands for the whole path of nested selectors not just for the immediate parent.