Overloaded operator usage is not highlighted

[EmrecanKaracayir]

Describe the bug
It is crucial to see when using operators like +, -, [] if they are overloaded, but in current implementation there is no visual feedback.

To Reproduce
Steps to reproduce the behavior:

1. Overload an operator on a class,
2. Use the overloaded operator in your code,
3. Observe no visual feedback given

Expected behavior
Like in C++, overloaded operators should be highlighted accordingly.

Screenshots

Please complete the following information:

• Operating System and version: on macos / Version 15.4.1 (Build 24E263)
• VS Code version: mac 1.99.3
• Dart extension version: 3.110.0
• Dart/Flutter SDK version: 3.7.2 (stable) (Tue Mar 11 04:27:50 2025 -0700) on "macos_arm64"
• Target device (if the issue relates to Flutter debugging): X

[EmrecanKaracayir]

This also posted on Dart-Code repository.

Dart-Code/Dart-Code#5508

[FMorschel]

I like the idea here.

I'm not sure how we should highlight [] uses. I mean, only the braces? The braces and the inner expression (also think about []=)?

Since they have the same base name, would users expect [] and []= to highlight together, like fields do?

CC @bwilkerson

[EmrecanKaracayir]

You can examine how C++ approaches this. It highlights only the overloaded operator like '[]' not the expression inside. Also Cmd or Control click goes to the overload declaration which is already implemented in Dart-Code extension.

C++ Examples:

[DanTup]

Is the request here to have different colouring for an operator depending on whether it's overridden?

I think there should definitely be a hover on them (for any dartdoc on the overridden method, and maybe even some text indicating it's overloaded) and Ctrl+Click should navigate, though I'm less sure I would expect to see the same operators in different colors depending on whether they were overloaded. I feel like that's an implementation detail that doesn't need to be visible all the time when viewing the code.

[EmrecanKaracayir]

As a developer i would like to distinguish that an operator used in code has custom algorithm behind it (overridden) visually. Because as you might guess overridden operators can act differently. Hover and navigation functionality is present, which is good, the only missing part is a visual feedback.

C++ extension assigns custom semantic tokens named "overloadedOperator" and "memberOverloadedOperator" and defaults to standard operator highlighting if user doesn't provide a color to these custom semantic tokens. Doing this way provides an alternative to who wanting to see a visual feedback.

[EmrecanKaracayir]

Oh, now I see... Every operator in Dart is overloaded isn't it? because there are no primitive types. If that's the case (every operator is overloaded) then this would not be useful.

[DanTup]

I'm not sure if the operators for the built-in types would be considered overloaded, my comment was more that I showing this information in the highlighting seems a little odd to me and something better suited to a hover. Although I was also thinking about operators like + where it's probably more obvious from the code that they're overloaded (since there's no default implementation of + on Object), but for == I guess the difference is more useful.

I think if this was done, it would be better as a modifier rather than a token type though, so that it can be customised but isn't different by default.

I'm interested in hearing the opinions of others too though.

[EmrecanKaracayir]

I think overloaded is a wrong term here, for Dart we should use overridden. And yes, '==' is a perfect example. I also agree of using modifiers instead of custom token types.