Validate that overloaded operations are distinguishable

[tidoust]

Web IDL defines a set of rules to assert whether two types are distinguishable, and thus whether a definition that includes overloaded operations is valid. These rules are not checked yet.

This gets a mention in #484 (comment) as "I'd consider that a separate issue", but since I could not spot a separate issue, I thought I'd create one ;)

[saschanaz]

I believe this is for webref, but currently I had to turn off no-duplicate since it's not straightforward to decide which spec to blame when it happens. Do you have a good idea? 🤔

[tidoust]

I'm not sure I get the no-duplicate comment? We should no longer have duplicate names in the curated data (and released NPM packages) of webref in particular.

For context, the starting point here was the Autoplay Policy Detection spec, see w3c/autoplay#21

On top of creating non distinguishable overloads, the approach that was envisioned in the spec turned out to be a bad one in any case but the point is that may be useful to validate the rules even when looking at a single spec.

[saschanaz]

Weird, I see several duplicates (not from webref but crawled with browser-specs):

Ignoring validation "no-duplicate" from portals. Details:
Validation error at line 2 in portals,4, inside `typedef MessageEventSource`:
 or HTMLPortalElement or PortalHost) MessageEventSource;
                                     ^ The name "MessageEventSource" of type "typedef" was already seen
Ignoring validation "no-duplicate" from permissions. Details:
Validation error at line 8 in permissions,2, inside `enum PermissionState`:
          enum PermissionState {
               ^ The name "PermissionState" of type "enum" was already seen
Ignoring validation "no-duplicate" from web-animations-1. Details:
Validation error at line 1 in web-animations-1,8, inside `enum FillMode`:
enum FillMode { "none", "forwards"
     ^ The name "FillMode" of type "enum" was already seen
Ignoring validation "no-duplicate" from web-animations-1. Details:
Validation error at line 2 in web-animations-1,22, inside `interface AnimationPlaybackEvent`:interface AnimationPlaybackEvent : Event {
          ^ The name "AnimationPlaybackEvent" of type "interface" was already seen
Ignoring validation "no-duplicate" from web-animations-1. Details:
Validation error at line 7 in web-animations-1,22, inside `dictionary AnimationPlaybackEventInit`:
dictionary AnimationPlaybackEventInit : EventInit {
           ^ The name "AnimationPlaybackEventInit" of type "dictionary" was already seen 

[tidoust]

Ah, if you run the crawl yourself, you'll have to fix the specs yourself too ;)

I was only talking about the curated data in webref, where curation refers to applying a set of Web IDL patches to the crawled Web IDL extracts in order to pass Web IDL validation. These patches currently include a patch for the Portals spec and the other examples you mentioned to get rid of duplicates.

Patches need to be maintained manually, especially for duplicates where there is indeed no simple way to decide which spec to blame.