ConvertForEachToForLoop fixer produces invalid syntax for expression function body with curly braces

[oprypin]

Example code (yes, it's very weird, this is a mistakenly written set literal):

  [1, -2].forEach((x) => {
        print('Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed $x')
      });

Actual replacement contains a syntax error:

  for (var x in [1, -2]) {
    {
        print('Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed $x')  // Error: Expected ';' after this.
      };
  }

[asashour]

For info, I guess this is case of unnecessary set literal, which is to be tackled soon, to trigger a warning, as reported in #50900, but the fix could also handle it.

[bwilkerson]

Rather than trying to handle the case of a literal set or map without type arguments as the return value value of the closure, I'd rather see the fix just not be offered in that case.

If we do try to fix it, I believe the fix requires adding the type arguments, not in removing the braces.