Right, but because VS Intellicode does not purely work on just the AST tree, that becomes its differentiated advantage. It's not a better way of autocomplete, but a different way that works for some scenarios. Because Intellicode is not deterministic, it is not meant to build muscle-memory like vim, emacs, etc.

I also see some comments in this thread wondering how it compares to Resharper so here's how I'd differentiate them:

Most of the previous autocomplete, "intellisense" type of algorithms work on parsing the AST of the project's source code. The lookup database is therefore scoped to the internal world of that project. Intellicode parses others' source code (e.g. top Github repos) which is out there in the external world.

What Intellicode does is use crowd-sourced data to create a different set of autocomplete suggestions. With that strategy, when one types the dot character "." to trigger a context menu for autocompletion, it's sort of a miniature "pagerank" of the most likely methods or properties instead of a "dumb" alphabetical order.

A concrete example in C# might be the autocomplete of a DateTime type. There are 2 similar properties: ".Now" and ".UtcNow".

What people probably want in many situations to avoid DST bugs is ".UtcNow" instead of ".Now". But in a regular IDE, a dumb alphabetical order means "N" shows up before "U".[0]. Therefore, newbies inadvertently end up with "DateTime.Now" in their code instead of "DateTime.UtcNow".

Something like Intellicode would use machine learning that analyzes the top Github repos and therefore reorder things so ".UtcNow" is higher than ".Now". Of course, this re-ordering could have been manually curated by C# experts into a "best practices database" but Intellicode's idea was to approximate that by using AI applied to others' source code.

[0] VS2017 screenshot example: https://imgur.com/a/05d9Ij9

Eh, isn't the whole point that intellicode is trained on your own project? Mine is, it suggests things based on our usage.

Intellicode may also be trained on your own project but that's definitely not its whole point.

Here's an excerpt from https://visualstudio.microsoft.com/services/intellicode/:

>"IntelliCode recommendations are based on thousands of open source projects on GitHub each with over 100 stars."

Perhaps you were thinking of "IntelliSense" instead of "IntelliCode"? Yes, the older IntelliSENSE could parse your custom classes and types and provide autocomplete for them. IntelliCODE is a different algorithm. (I think Microsoft's naming for them is not self-descriptive and confusing.)

I've only ever noticed the "starred" recommendations on our own methods, and it's incredible.

    class ComponentName extends React.|

Reliability and predictability matters a lot in interface design

Perfectly said. I've always thought the same way. Basically, I'd rather not use a "pretty good" auto complete, because "pretty good" usually means it does more harm than good (where harm is providing wrong results or doing anything that slows me down overall).