==== tests/cases/compiler/implicitAnyFunctionReturnNullOrUndefined.ts (4 errors) ====
    // this should be an error
    function nullWidenFunction() { return null;}             // error at "nullWidenFunction"
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! 'nullWidenFunction', which lacks return-type annotation, implicitly has an 'any' return type.
    function undefinedWidenFunction() { return undefined; }  // error at "undefinedWidenFunction"
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! 'undefinedWidenFunction', which lacks return-type annotation, implicitly has an 'any' return type.
    
    class C {
        nullWidenFuncOfC() {  // error at "nullWidenFuncOfC"
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            return null;
    ~~~~~~~~~~~~~~~~~~~~
        }
    ~~~~~
!!! 'nullWidenFuncOfC', which lacks return-type annotation, implicitly has an 'any' return type.
    
        underfinedWidenFuncOfC() {  // error at "underfinedWidenFuncOfC"
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            return undefined;
    ~~~~~~~~~~~~~~~~~~~~~~~~~
        }
    ~~~~~
!!! 'underfinedWidenFuncOfC', which lacks return-type annotation, implicitly has an 'any' return type.
    }
    
    // this should not be an error
    function foo1(): any { return null; }
    function bar1(): any { return undefined; }
    function fooBar(): number { return 1; }
    function fooFoo() { return 5; }
    
    // this should not be an error as the error is raised by expr above
    nullWidenFunction();
    undefinedWidenFunction();