[clang] Reapply "[Clang] Transform lambda's constraints when instantiating parameter mapping (PR #207966)

[Corentin Jabot via cfe-commits]

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@@ -1028,7 +1021,7 @@ ExprResult ConstraintSatisfactionChecker::EvaluateSlow(
       ConceptId->getFoundDecl(), ConceptId->getNamedConcept(), &OutArgs,
       /*DoCheckConstraintSatisfaction=*/false);
 
-  if (SubstitutedConceptId.isInvalid() || Trap.hasErrorOccurred())
+  if (SubstitutedConceptId.isInvalid())
     return ExprError();
 
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cor3ntin wrote:

> FWIW we should get rid of uses of hasErrorOccurred(), in favor of not performing error recovery in SFINAE context,

Maybe - but either way, why is this change necessary in the context of this PR?

https://github.com/llvm/llvm-project/pull/207966