diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 77f1b9b0d707..2aeaecf9cd90 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -10892,6 +10892,9 @@ def confusing_hyperobject : Error<
 def incomplete_hyperobject : Error<
    "incomplete type %0 may not be a hyperobject">;
 
+def qualified_hyperobject : Error<
+   "qualified type %0 may not be a hyperobject">;
+
 def nested_hyperobject : Error<
    "type %0, which contains a hyperobject, may not be a hyperobject">;
 
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 63ac68a39f96..ad2110207729 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -2495,6 +2495,12 @@ QualType Sema::BuildHyperobjectType(QualType Element, Expr *Identity,
       Diag(Loc, *Code) << Element;
   }
 
+  if (Element.isConstQualified() || Element.isVolatileQualified()) {
+    Diag(Loc, diag::qualified_hyperobject) << Element;
+    // Volatile reducers generate confusing diagnostics when used.
+    Element.removeLocalVolatile();
+  }
+
   Identity = ValidateReducerCallback(Identity, 1, Loc);
   Reduce = ValidateReducerCallback(Reduce, 2, Loc);
 
diff --git a/clang/test/Cilk/hyper-errors.c b/clang/test/Cilk/hyper-errors.c
index 5458face1382..c342a82df0cd 100644
--- a/clang/test/Cilk/hyper-errors.c
+++ b/clang/test/Cilk/hyper-errors.c
@@ -37,4 +37,16 @@ void function() {
   // expected-error@-2{{use of undeclared identifier 'typo3'}}
   int _Hyperobject(0, typo4) var3 = 0;
   // expected-error@-1{{use of undeclared identifier 'typo4'}}
+  const int _Hyperobject(identity, reduce) var4 = 0;
+  // expected-error@-1{{qualified type 'const int' may not be a hyperobject}}
+  volatile int _Hyperobject(identity, reduce) var5 = 0;
+  // expected-error@-1{{qualified type 'volatile int' may not be a hyperobject}}
+  typedef const int c_int;
+  c_int _Hyperobject(identity, reduce) var6 = 0;
+  // expected-error@-1{{qualified type 'c_int' (aka 'const int') may not be a hyperobject}}
+  ++var4;
+  // expected-error@-1{{read-only variable is not assignable}}
+  ++var5;
+  ++var6;
+  // expected-error@-1{{read-only variable is not assignable}}
 }