1/3: Building Mod1 (Mod1.idr)
2/3: Building Mod2 (Mod2.idr)
3/3: Building Mod (Mod.idr)
Error: While processing right hand side of main. Undefined name foo. 

Mod:5:16--5:19
 1 | import Mod1
 2 | import Mod2
 3 | 
 4 | main : IO ()
 5 | main = printLn foo
                    ^^^
Did you mean any of: for, Mod1.foo (not exported), or Mod2.foo (not exported)?