fix unused variables in condition warning

for 92023b1

Author: metaflow

clang/include/clang/AST/DeclTemplate.h

@@ -377,7 +377,8 @@ class DefaultArgStorage {
     InheritedFrom = getParmOwningDefaultArg(InheritedFrom);
     if (!isSet())
       ValueOrInherited = InheritedFrom;
-    else if (auto *D = ValueOrInherited.template dyn_cast<ParmDecl *>()) {
+    else if ([[maybe_unused]] auto *D =
+                 ValueOrInherited.template dyn_cast<ParmDecl *>()) {
       assert(C.isSameDefaultTemplateArgument(D, InheritedFrom));
       ValueOrInherited =
           new (allocateDefaultArgStorageChain(C)) Chain{InheritedFrom, get()};

clang/lib/AST/Interp/ByteCodeExprGen.cpp

@@ -1670,7 +1670,7 @@ template <class Emitter>
 std::optional<unsigned>
 ByteCodeExprGen<Emitter>::allocateLocal(DeclTy &&Src, bool IsExtended) {
   // Make sure we don't accidentally register the same decl twice.
-  if (const auto *VD =
+  if ([[maybe_unused]]  const auto *VD =
           dyn_cast_if_present<ValueDecl>(Src.dyn_cast<const Decl *>())) {
     assert(!P.getGlobal(VD));
     assert(!Locals.contains(VD));