[clang] [clang-tools-extra] [clang] Skip suggesting unqualified members in explicit-object member functions (PR #153760)

[Nathan Ridge via cfe-commits]

================
@@ -1428,6 +1428,16 @@ void ResultBuilder::AddResult(Result R, DeclContext *CurContext,
 
   AdjustResultPriorityForDecl(R);
 
+  if (isa<FieldDecl>(R.Declaration)) {
+    // If result is a member in the context of an explicit-object member
+    // function, drop it because it must be accessed through the object
+    // parameter
+    if (auto *MethodDecl = dyn_cast<CXXMethodDecl>(CurContext);
----------------
HighCommander4 wrote:

I don't think `CurContext` is the right `DeclContext` to check here, as it could be a nested context inside the method. For example:

```c++
struct A {
  int member;
  void foo(this A &self) {
    [&]() {
      // Completion should not offer `member`, but with the current patch it does.
      mem^
    }();
  }
};
```

I think you want something like `getFunctionLevelDeclContext(/*AllowLambda=*/false)`.

Also, as mentioned on Discord, we should do this check in `CodeCompleteOrdinaryName()` and save the result on the `ResultBuilder`. This is actually important not just for performance, but also to limit the effect of the change to cases where we're in `CodeCompleteOrdinaryName()`, since `ResultBuilder` is used for completions in other contexts as well.

https://github.com/llvm/llvm-project/pull/153760