// (Closure primitive rewrites, etc) runs before the Normalize pass,
// so this can't be force on everywhere.
if (normalizeEnabled) {
new Normalize(compiler, true).process(
normalizeCheckExternsRootClone, normalizeCheckMainRootClone);
explanation = normalizeCheckMainRootClone.checkTreeEquals(mainRoot);
assertNull("Normalization invalidated." +
"\nExpected: " +
compiler.toSource(normalizeCheckMainRootClone) +
"\nResult: " + compiler.toSource(mainRoot) +
"\n" + explanation, explanation);