[clang] [Clang][C++23] Core language changes from P1467R9 extended floating-point types and standard names. (PR #78503)

[via cfe-commits]

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@@ -1032,6 +1033,21 @@ NumericLiteralParser::NumericLiteralParser(StringRef TokSpelling,
 
       isFloat = true;
       continue;  // Success.
+    // C++23 5.13.4 [lex.fcon]
+    case 'b':
+    case 'B':
+      if (!isFPConstant)
+        break; // Error for integer constant.
+      if (s + 3 < ThisTokEnd && (s[1] == 'f' || s[1] == 'F') && s[2] == '1' &&
+          s[3] == '6') {
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cor3ntin wrote:

This allows for `Bf` and `bF` which are not supposed to be allowed to work.
I'd rather we use StringRef::compare

https://github.com/llvm/llvm-project/pull/78503