src/index.ts(5,7): error TS2304: Cannot find name 'foo'.
src/index.ts(12,18): error TS7006: Parameter 'x' implicitly has an 'any' type.
src/util.ts(3,1): warning TS6133: 'unused' is declared but its value is never read.

Found 2 errors and 1 warning in 2 files.
