Name resolution bug

The following module code throws an exception:

// constructor function
function PengMod(a) {
      // "a" will be resolved with the method a not with the locale variable a.
      console.log( a );
      if (a !== "hello" ) throw Error("Bug!");
}

// This function masks the local variable a in the constructor!!!
PengMod.a = function () {
};

new PengMod( "hello" );

The code is a snippet from a larger module which must be minified because of its size. I cannot rename the method oder variable because the names come from a minification step with name mangling. The transpiler always starts in every new scope with a, b, c, .

Any ideas?