[clang][dataflow][NFC] Eliminate unnecessary helper `stripReference()`.

[mboehme]

Summary

QualType::getNonReferenceType() does the same thing.

[sammccall]

This looks equivalent to me.

clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp

if (HasValueVal == nullptr) {
       HasValueVal = &Env.makeAtomicBoolValue();
       OptionalVal->setProperty("has_value", *HasValueVal);
     }
     return HasValueVal;
   }
   return nullptr;
 }
 
-/// If `Type` is a reference type, returns the type of its pointee. Otherwise,
-/// returns `Type` itself.
-QualType stripReference(QualType Type) {
-  return Type->isReferenceType() ? Type->getPointeeType() : Type;
-}
-
 /// Returns true if and only if `Type` is an optional type.
 bool isOptionalType(QualType Type) {
   if (!Type->isRecordType())
     return false;
   const CXXRecordDecl *D = Type->getAsCXXRecordDecl();
   return D != nullptr && hasOptionalClassName(*D);
 }
 
if (Env.getValue(ValueLoc) == nullptr) {
       auto *ValueVal = Env.createValue(ValueLoc.getType());
       if (ValueVal == nullptr)
         return nullptr;
       Env.setValue(ValueLoc, *ValueVal);
     }
     return &ValueLoc;
   }
 
-  auto Ty = stripReference(Q);
+  auto Ty = Q.getNonReferenceType();
   auto *ValueVal = Env.createValue(Ty);
   if (ValueVal == nullptr)
     return nullptr;
   auto &ValueLoc = Env.createStorageLocation(Ty);
   Env.setValue(ValueLoc, *ValueVal);
   auto &ValueRef = Env.create<ReferenceValue>(ValueLoc);
   OptionalVal.setProperty("value", ValueRef);
   return &ValueLoc;

 /// value that is constructed/assigned from a value of type `U` or `optional<U>`
 /// where `T` is constructible from `U`.
 BoolValue &valueOrConversionHasValue(const FunctionDecl &F, const Expr &E,
                                      const MatchFinder::MatchResult &MatchRes,
                                      LatticeTransferState &State) {
   assert(F.getTemplateSpecializationArgs() != nullptr);
   assert(F.getTemplateSpecializationArgs()->size() > 0);
 
-  const int TemplateParamOptionalWrappersCount = countOptionalWrappers(
-      *MatchRes.Context,
-      stripReference(F.getTemplateSpecializationArgs()->get(0).getAsType()));
-  const int ArgTypeOptionalWrappersCount =
-      countOptionalWrappers(*MatchRes.Context, stripReference(E.getType()));
+  const int TemplateParamOptionalWrappersCount =
+      countOptionalWrappers(*MatchRes.Context, F.getTemplateSpecializationArgs()
+                                                   ->get(0)
+                                                   .getAsType()
+                                                   .getNonReferenceType());
+  const int ArgTypeOptionalWrappersCount = countOptionalWrappers(
+      *MatchRes.Context, E.getType().getNonReferenceType());
 
   // Check if this is a constructor/assignment call for `optional<T>` with
   // argument of type `U` such that `T` is constructible from `U`.
   if (TemplateParamOptionalWrappersCount == ArgTypeOptionalWrappersCount)
     return State.Env.getBoolLiteralValue(true);
 
   // This is a constructor/assignment call for `optional<T>` with argument of
   // type `optional<U>` such that `T` is constructible from `U`.