[clang] [clang-tools-extra] [clang] improve class type sugar preservation in pointers to members (PR #130537)

[Erich Keane via cfe-commits]

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@@ -13461,13 +13486,112 @@ static ElaboratedTypeKeyword getCommonTypeKeyword(const T *X, const T *Y) {
                                             : ElaboratedTypeKeyword::None;
 }
 
+static NestedNameSpecifier *getCommonNNS(ASTContext &Ctx,
+                                         NestedNameSpecifier *X,
+                                         NestedNameSpecifier *Y, bool Sugar) {
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erichkeane wrote:

What does `Sugar` mean here?  Also, instead of `X` and `Y`, `NNS1` and `NNS2` or `LHS` and `RHS` or something would be at least somewhat descriptive?  We show a preference for the `X` in at least a handful of places it seems, so perhaps a name that implies that?  

https://github.com/llvm/llvm-project/pull/130537