Suggestions for misspelled properties and variables (based on Levenshtein distance for variables/properties in scope)

[artr73]

Consider the following code:

class X {
  public longName = 10;
  public otherName = 11;

  public do(){
    this.lognName = 20;
  }
}

Currently compilation fails with the message:

Property 'lognName' does not exist on the type 'X'.

In case when a variable is misspelled, the error is even less helpful:

public longMethod(){
  let firstVariable = 10;
  let secondVariable = "hello,world";
  
  //lots of code here
  fristVariable = 20;
}

Cannot find name 'fristVariable'.

It could offer variable/property suggestion, like:

Cannot find name 'fristVariable'. Did you mean 'firstVariable'?

For example, Rust compiler (1.16) would suggest an existing variable that most resembles the misspelled one, based on Levenstein distance, if I'm correct.

[RyanCavanaugh]

@sandersn notes from backlog slog:

• Do some sort of limiting to avoid this being too expensive (caching? limit the number of times we do this? etc?)
• Levensthein / Hamming / Shiveldistance is up to you
• Have some minimal threshold of "might be close enough"
• Filter based on the kind of symbol (value / namespace / type) to make sure we only suggest valid stuff
• Include a quickfix
• Everyone's gonna 😍 this

[sandersn]

You can track the progress of this at the branch sandersn/did-you-mean. It's at a very early stage right now -- the suggested replacement is the first name whose length is no more than 3 different from the misspelled name's length. This works pretty well for property accesses for but lone identifiers tends to suggest NaN and Infinity.

There's a quick fix for property accesses. My next step is to make it work for standalone identifiers as well.

[Igorbek]

Should intellisense also suggest something when you misspell?

[sandersn]

Are you saying that it should provide spelling corrections when the list would otherwise be empty? For example, when the very first letter is misspelled? I think that could work, but I'd have to play around with it to know for sure.

[Igorbek]

@sandersn yes, exactly