asiAmbientFunctionDeclaration.ts(1,18): error TS7010: 'foo', which lacks return-type annotation, implicitly has an 'any' return type.


==== asiAmbientFunctionDeclaration.ts (1 errors) ====
    declare function foo()
                     ~~~
!!! error TS7010: 'foo', which lacks return-type annotation, implicitly has an 'any' return type.