[clang] [RFC] Reapply "[Clang] Implement P3034R1 Module Declarations Shouldn’t be Macros" (PR #102135)

[via cfe-commits]

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@@ -136,6 +136,8 @@ class Lexer : public PreprocessorLexer {
 
   bool IsAtPhysicalStartOfLine;
 
+  bool IsCurrentLexingTokAtPhysicalStartOfLine;
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cor3ntin wrote:

we have IsAtStartOfLine and IsAtPhysicalStartOfLine - Why do we need a third one?

https://github.com/llvm/llvm-project/pull/102135