[clang] [clang] Fix alias declaration fix-it location for token-split '>>' (PR #184555)

[via cfe-commits]

================
@@ -862,8 +862,17 @@ SourceLocation Lexer::getLocForEndOfToken(SourceLocation Loc, unsigned Offset,
     return {};
 
   if (Loc.isMacroID()) {
----------------
luoliwoshang wrote:

Thanks for the question. The reason this is in the `isMacroID()` branch is that `isMacroID()` only checks `MacroIDBit`; it does not distinguish how that bit was produced.

In this testcase there is no user macro, but `>>` is split during template parsing via `PP.SplitToken`. After that, the location goes through `createTokenSplitLoc -> createExpansionLocImpl -> getMacroLoc`, so the location carries `MacroIDBit` and naturally enters the `isMacroID()` path.


https://github.com/llvm/llvm-project/pull/184555