[clang] [clang] SemaConcept.cpp - fix MSVC "not all control paths return a value" warnings. NFC. (PR #162060)

[Simon Pilgrim via cfe-commits]

https://github.com/RKSimon created https://github.com/llvm/llvm-project/pull/162060

None

>From aa1268dfc2e87b652c785ae3dd5aa0db7767ba15 Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev at redking.me.uk>
Date: Mon, 6 Oct 2025 11:05:27 +0100
Subject: [PATCH] [clang] SemaConcept.cpp - fix MSVC "not all control paths
 return a value" warnings. NFC.

---
 clang/lib/Sema/SemaConcept.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Sema/SemaConcept.cpp b/clang/lib/Sema/SemaConcept.cpp
index 11d2d5c3938c1..999e302c02535 100644
--- a/clang/lib/Sema/SemaConcept.cpp
+++ b/clang/lib/Sema/SemaConcept.cpp
@@ -1049,6 +1049,7 @@ ExprResult ConstraintSatisfactionChecker::Evaluate(
   case NormalizedConstraint::ConstraintKind::Compound:
     return Evaluate(static_cast<const CompoundConstraint &>(Constraint), MLTAL);
   }
+  llvm_unreachable("Unknown ConstraintKind enum");
 }
 
 static bool CheckConstraintSatisfaction(
@@ -2141,6 +2142,7 @@ bool SubstituteParameterMappings::substitute(NormalizedConstraint &N) {
     return substitute(Compound.getRHS());
   }
   }
+  llvm_unreachable("Unknown ConstraintKind enum");
 }
 
 } // namespace
@@ -2561,7 +2563,6 @@ FormulaType SubsumptionChecker::Normalize(const NormalizedConstraint &NC) {
   };
 
   switch (NC.getKind()) {
-
   case NormalizedConstraint::ConstraintKind::Atomic:
     return {{find(&static_cast<const AtomicConstraint &>(NC))}};
 
@@ -2601,6 +2602,7 @@ FormulaType SubsumptionChecker::Normalize(const NormalizedConstraint &NC) {
     return Res;
   }
   }
+  llvm_unreachable("Unknown ConstraintKind enum");
 }
 
 void SubsumptionChecker::AddUniqueClauseToFormula(Formula &F, Clause C) {