[clang] [Clang] Report an error and crash on source location exhaustion in macros (PR #69908)

[Sam McCall via cfe-commits]

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@@ -356,6 +356,8 @@ def err_file_modified : Error<
   "file '%0' modified since it was first processed">, DefaultFatal;
 def err_file_too_large : Error<
   "sorry, unsupported: file '%0' is too large for Clang to process">;
+def err_expansions_too_large : Error<
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sam-mccall wrote:

FWIW, I'm not sure the *why* matters much: this is ~always going to be the sum of thousands of tiny things. So we could consider merging err_expansions_too_large and err_include_too_large. (And also emitting that in ASTReader.cpp above remark_sloc_usage).
But I don't feel strongly.

https://github.com/llvm/llvm-project/pull/69908