If you face Failed to save undefined: No COMPONENT named markup://use found : [markup://c:AppAssignmentComponent], use <span> tag instead of <use> tag. 

Exception:

Failed to save undefined: No COMPONENT named markup://use found : [markup://c:AppAssignmentComponent]

Resolution:

Use <span> tag instead of <use> tag.

Note: Make sure you have created the svg or svgicon lighting component.