Typo correction should be smarter about context

[AaronBallman]

Currently, typo correction has very little intelligence about the context of the typo being corrected. As a result, we fail to suggest corrections as well as we could. For example:

This case fails to recognize we're in a context where we expect one of a handful of keywords:

struct S {
  S() = defaul;
};

https://godbolt.org/z/o4snPEGve
(The same applies in many other circumstances; we should have a general mechanism that filters keywords by context.)

This case fails to recognize a type is invalid (but only in C) and suggests we replace lock by long:

void func() {
  long x;
  x = (lock);
}

https://godbolt.org/z/cxbjbE1bP

This case fails to recognize that only a type is valid:

int lang;
int main() {
  (void)(ling)12;
}

https://godbolt.org/z/hc3rnrbKz

I expect more examples exist. The thrust of the request is to make typo correction a bit more situationally aware whenever possible.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Aaron Ballman (AaronBallman)

Currently, typo correction has very little intelligence about the context of the typo being corrected. As a result, we fail to suggest corrections as well as we could. For example:

This case fails to recognize we're in a context where we expect one of a handful of keywords:

struct S {
  S() = defaul;
};

https://godbolt.org/z/o4snPEGve
(The same applies in many other circumstances; we should have a general mechanism that filters keywords by context.)

This case fails to recognize a type is invalid (but only in C) and suggests we replace lock by long:

void func() {
  long x;
  x = (lock);
}

https://godbolt.org/z/cxbjbE1bP

This case fails to recognize that only a type is valid:

int lang;
int main() {
  (void)(ling)12;
}

https://godbolt.org/z/hc3rnrbKz

I expect more examples exist. The thrust of the request is to make typo correction a bit more situationally aware whenever possible.

[AaronBallman]

@cor3ntin made a good observation offline, this sounds like it has some overlap with code completion facilities which typically are more context sensitive. Perhaps that's an opportunity for code sharing.