Fix #1589: Reworks with explanation error:modifiers(s) not allowed for 'item'

[johnregan]

Parsers-1685 : Sample compilation error

-- [E082] Syntax Error: /home/jr/projects/dotty/tests/neg/validate-parsing.scala:4:7 
4 |  lazy trait T // error: modifier(s) `lazy' not allowed for trait
  |       ^^^^^
  |       modifier(s) `lazy' not allowed for trait

Explanation

You tried to use a modifier that is inapplicable for the type of item under modification

Consider the following example:
sealed def y: Int = 1
In this instance, the modifier 'sealed' is not applicable to the item type 'def' (method)

[dottybot]

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[johnregan]

@felixmulder can you take a look ?

[felixmulder]

Minor nitpicks, otherwise LGTM! Thanks for contributing! 🎉

[felixmulder]

The idea with having this on a separate line is that we won't get a - diff when adding an ID

[felixmulder]

We could also possibly try to identify which flags have been applied to what and make a suggestion. That would be cool 😄

[johnregan]

@felixmulder not quite sure how to identify all modifiers for traits,methods,variables. Should this not be handled instead by the next error,
1693 syntaxError(s"illegal modifier combination: ${mods.flags} and $flag")

[felixmulder]

Hmm, I think these two should be harmonized. I.e. the same error message for both. You could make sort: Option[String] to discern between the case _ and the rest of them.

Otherwise this LGTM now :)

[johnregan]

Cool, I can take that one next. Can we agree that it will be handled with the 1693 consolidation refactor and get this one through? :)

[felixmulder]

Sure - that's fine by me - assigning you in #1589

[nicolasstucki]

You should leave the trailing , at the end so the next diff wont change this line

  ...
  AnonymousFunctionMissingParamTypeID,
  SuperCallsNotAllowedInlineID,
  ModifiersNotAllowedID,
  ;

[johnregan]

ok thanks nicolass