diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize-loop-convert-const.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize-loop-convert-const.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize-loop-convert-const.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize-loop-convert-const.cpp
@@ -10,12 +10,12 @@
 };
 
 // This class is non-trivially copyable because the copy-constructor and copy
-// assignment take non-const references.
+// assignment take non-const references and are user-provided.
 struct ModifiesRightSide {
   ModifiesRightSide() = default;
-  ModifiesRightSide(ModifiesRightSide &) = default;
+  ModifiesRightSide(ModifiesRightSide &);
   bool operator<(ModifiesRightSide &) const;
-  ModifiesRightSide &operator=(ModifiesRightSide &) = default;
+  ModifiesRightSide &operator=(ModifiesRightSide &);
 };
 
 template <typename T>
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
@@ -9772,11 +9772,9 @@
 
   case CXXCopyConstructor:
   case CXXCopyAssignment: {
-    // Trivial copy operations always have const, non-volatile parameter types.
-    ConstArg = true;
     const ParmVarDecl *Param0 = MD->getParamDecl(0);
     const ReferenceType *RT = Param0->getType()->getAs<ReferenceType>();
-    if (!RT || RT->getPointeeType().getCVRQualifiers() != Qualifiers::Const) {
+    if (!RT) {
       if (Diagnose)
         Diag(Param0->getLocation(), diag::note_nontrivial_param_type)
           << Param0->getSourceRange() << Param0->getType()
@@ -9784,6 +9782,11 @@
                Context.getRecordType(RD).withConst());
       return false;
     }
+
+    if (RT && ((RT->getPointeeType().getCVRQualifiers() & Qualifiers::Const) ==
+               Qualifiers::Const)) {
+      ConstArg = true;
+    }
     break;
   }
 
diff --git a/clang/test/CXX/special/class.copy/p12-0x.cpp b/clang/test/CXX/special/class.copy/p12-0x.cpp
--- a/clang/test/CXX/special/class.copy/p12-0x.cpp
+++ b/clang/test/CXX/special/class.copy/p12-0x.cpp
@@ -28,7 +28,18 @@
 struct NonConstCopy {
   NonConstCopy(NonConstCopy &) = default;
 };
-using _ = not_trivially_copyable<NonConstCopy>;
+static_assert(__has_trivial_copy(NonConstCopy), "");
+static_assert(__is_trivially_constructible(NonConstCopy, NonConstCopy &), "");
+static_assert(!__is_trivially_constructible(NonConstCopy, NonConstCopy), "");
+static_assert(!__is_trivially_constructible(NonConstCopy, const NonConstCopy &), "");
+static_assert(!__is_trivially_constructible(NonConstCopy, NonConstCopy &&), "");
+
+struct DefaultedSpecialMembers {
+  DefaultedSpecialMembers(const DefaultedSpecialMembers &) = default;
+  DefaultedSpecialMembers(DefaultedSpecialMembers &) = default;
+  DefaultedSpecialMembers(DefaultedSpecialMembers &&) = default;
+};
+using _ = trivially_copyable<DefaultedSpecialMembers>;
 
 // class X has no virtual functions
 struct VFn {
diff --git a/clang/test/CXX/special/class.copy/p25-0x.cpp b/clang/test/CXX/special/class.copy/p25-0x.cpp
--- a/clang/test/CXX/special/class.copy/p25-0x.cpp
+++ b/clang/test/CXX/special/class.copy/p25-0x.cpp
@@ -31,7 +31,22 @@
 struct NonConstCopy {
   NonConstCopy &operator=(NonConstCopy &) = default;
 };
-using _ = not_trivially_assignable<NonConstCopy>;
+static_assert(__has_trivial_assign(NonConstCopy), "");
+static_assert(__is_trivially_assignable(NonConstCopy &, NonConstCopy &), "");
+static_assert(!__is_trivially_assignable(NonConstCopy &, const NonConstCopy &), "");
+static_assert(!__is_trivially_assignable(NonConstCopy &, NonConstCopy), "");
+static_assert(!__is_trivially_assignable(NonConstCopy &, NonConstCopy &&), "");
+static_assert(__is_trivially_assignable(NonConstCopy &&, NonConstCopy &), "");
+static_assert(!__is_trivially_assignable(NonConstCopy &&, const NonConstCopy &), "");
+static_assert(!__is_trivially_assignable(NonConstCopy &&, NonConstCopy), "");
+static_assert(!__is_trivially_assignable(NonConstCopy &&, NonConstCopy &&), "");
+
+struct DefaultedSpecialMembers {
+  DefaultedSpecialMembers &operator=(const DefaultedSpecialMembers &) = default;
+  DefaultedSpecialMembers &operator=(DefaultedSpecialMembers &) = default;
+  DefaultedSpecialMembers &operator=(DefaultedSpecialMembers &&) = default;
+};
+using _ = trivially_assignable<DefaultedSpecialMembers>;
 
 // class X has no virtual functions
 struct VFn {