diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -7007,11 +7007,9 @@
   "volatile qualifier in structured binding declaration is deprecated">,
   InGroup<DeprecatedVolatile>;
 
-def err_catch_incomplete_ptr : Error<
-  "cannot catch pointer to incomplete type %0">;
-def err_catch_incomplete_ref : Error<
-  "cannot catch reference to incomplete type %0">;
-def err_catch_incomplete : Error<"cannot catch incomplete type %0">;
+def err_catch_incomplete_or_sizeless : Error<
+  "cannot catch %select{|pointer to |reference to }0"
+  "%select{incomplete|sizeless}1 type %2">;
 def err_catch_rvalue_ref : Error<"cannot catch exceptions by rvalue reference">;
 def err_catch_variably_modified : Error<
   "cannot catch variably modified type %0">;
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -15472,19 +15472,18 @@
 
   QualType BaseType = ExDeclType;
   int Mode = 0; // 0 for direct type, 1 for pointer, 2 for reference
-  unsigned DK = diag::err_catch_incomplete;
   if (const PointerType *Ptr = BaseType->getAs<PointerType>()) {
     BaseType = Ptr->getPointeeType();
     Mode = 1;
-    DK = diag::err_catch_incomplete_ptr;
   } else if (const ReferenceType *Ref = BaseType->getAs<ReferenceType>()) {
     // For the purpose of error recovery, we treat rvalue refs like lvalue refs.
     BaseType = Ref->getPointeeType();
     Mode = 2;
-    DK = diag::err_catch_incomplete_ref;
   }
   if (!Invalid && (Mode == 0 || !BaseType->isVoidType()) &&
-      !BaseType->isDependentType() && RequireCompleteType(Loc, BaseType, DK))
+      !BaseType->isDependentType() &&
+      RequireCompleteSizedType(Loc, BaseType,
+                               diag::err_catch_incomplete_or_sizeless, Mode))
     Invalid = true;
 
   if (!Invalid && !ExDeclType->isDependentType() &&
diff --git a/clang/test/SemaCXX/sizeless-1.cpp b/clang/test/SemaCXX/sizeless-1.cpp
--- a/clang/test/SemaCXX/sizeless-1.cpp
+++ b/clang/test/SemaCXX/sizeless-1.cpp
@@ -399,6 +399,19 @@
   throw local_int8;      // expected-error {{cannot throw object of sizeless type 'svint8_t'}}
   throw global_int8_ptr; // expected-error {{cannot throw pointer to object of sizeless type 'svint8_t'}}
 
+  try {
+  } catch (int) {
+  }
+  try {
+  } catch (svint8_t) { // expected-error {{cannot catch sizeless type 'svint8_t'}}
+  }
+  try {
+  } catch (svint8_t *) { // expected-error {{cannot catch pointer to sizeless type 'svint8_t'}}
+  }
+  try {
+  } catch (svint8_t &) { // expected-error {{cannot catch reference to sizeless type 'svint8_t'}}
+  }
+
   local_int8.~__SVInt8_t(); // expected-error {{object expression of non-scalar type 'svint8_t' (aka '__SVInt8_t') cannot be used in a pseudo-destructor expression}}
 
   (void)svint8_t();