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

[Joshua Cranmer via llvm-commits]

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@@ -11226,12 +11232,14 @@ void Sema::CheckImplicitConversion(Expr *E, QualType T, SourceLocation CC,
         DiagnoseImpCast(*this, E, T, CC, diag::warn_impcast_float_precision);
       }
       // ... or possibly if we're increasing rank, too
-      else if (Order < 0) {
+      else if (Order == FRCR_Lesser) {
         if (SourceMgr.isInSystemMacro(CC))
           return;
 
         DiagnoseImpCast(*this, E, T, CC, diag::warn_impcast_double_promotion);
       }
+      assert(Order != FRCR_Unordered &&
+             "Unordered floating types are not allowed.");
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jcranmer-intel wrote:

Maybe mention "in implicit conversion" in the message here?

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