[clang] [libcxx] [Clang] Implement CWG2369 "Ordering between constraints and substitution" (PR #102857)

[via cfe-commits]

================
@@ -4042,8 +4062,8 @@ TemplateDeductionResult Sema::FinishTemplateArgumentDeduction(
   //   ([temp.constr.decl]), those constraints are checked for satisfaction
   //   ([temp.constr.constr]). If the constraints are not satisfied, type
   //   deduction fails.
-  if (!IsIncomplete) {
-    if (CheckInstantiatedFunctionTemplateConstraints(
+  if (IsLambda && !IsIncomplete) {
----------------
cor3ntin wrote:

can you add a fixme comment here?

https://github.com/llvm/llvm-project/pull/102857