1 files changed, 4 insertions, 3 deletions
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 6887962940e..d28354f6e82 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -650,10 +650,11 @@ bool Sema::MergeCXXFunctionDecl(FunctionDecl *New, FunctionDecl *Old,
   // FIXME: It's not clear what should happen if multiple declarations of a
   // deduction guide have different explicitness. For now at least we simply
   // reject any case where the explicitness changes.
-  if (New->isDeductionGuide() &&
-      New->isExplicitSpecified() != Old->isExplicitSpecified()) {
+  auto *NewGuide = dyn_cast<CXXDeductionGuideDecl>(New);
+  if (NewGuide && NewGuide->isExplicitSpecified() !=
+                      cast<CXXDeductionGuideDecl>(Old)->isExplicitSpecified()) {
     Diag(New->getLocation(), diag::err_deduction_guide_explicit_mismatch)
-      << New->isExplicitSpecified();
+      << NewGuide->isExplicitSpecified();
     Diag(Old->getLocation(), diag::note_previous_declaration);
   }