Local functions are wrongly made global in Strict mode

When strict mode is enabled, the following code triggers an error for the second call to func1:

'use strict';
{
    function func1(arg){ //func1 is local to the scope, not global
        alert(arg) ;
    }
    func1('Hi') ;
}

func1('Hi') ; // <-- Error: func1 does not exist globally

When we compile that code:

java -jar closure-compiler-v20190121.jar --language_out NO_TRANSPILE -O SIMPLE  --js_output_file Output.js Input.js

We get:

'use strict';
var func1 = function(a) {
  alert(a);
};
func1("Hi");
func1("Hi");

i.e. func1 was converted to a global function, which makes the code behave different than the original.

[Getfree]

There’s no solution so far, but there is a workaround.

Instead of this:

{
    function func(){ . . . }
}

Do this:

{
    let func = function(){ . . . } ;
}

In the first case, func may be global or local depending on whether strict mode is in effect or not. And that’s probably the reason why Closure Compiler gets it wrong.

Whereas in the second case, func is always local, so Closure Compiler doesn’t get confused.

[devalnor]

Any news about this issue? Did you find a solution?