fixed typo

Author: AntonNM

inst/tests/tests.Rraw

@@ -21068,7 +21068,7 @@ test(2305, { fread(testDir("issue_6729.txt.bz2")); TRUE })
 # j expressions that modify a data.table by reference, (#6768)
 inner=function(dt){dt[,b:=4:6]}
 outer=function(dt){inner(dt); return(7:9)}
-foo=function(dt){dt[b:=4:6];return(7:9)}
+foo=function(dt){dt[,b:=4:6];return(7:9)}
 DT = data.table(a=1:3)
 test(2306, DT[,c:=outer(DT)], data.table(a=1:3, b=4:6, c=7:9))
 test(2306.1, DT[,c:=foo(DT)], data.table(a=1:3, b=4:6, c=7:9))