diff --git a/layout/generic/nsQueryFrame.h b/layout/generic/nsQueryFrame.h
index 5eb8e1186450..326b29266c96 100644
--- a/layout/generic/nsQueryFrame.h
+++ b/layout/generic/nsQueryFrame.h
@@ -25,23 +25,22 @@
 #define NS_QUERYFRAME_HEAD(class)               \
   void* class ::QueryFrame(FrameIID id) const { \
     switch (id) {
-#define NS_QUERYFRAME_ENTRY(class)                                            \
-  case class ::kFrameIID: {                                                   \
-    static_assert(                                                            \
-        mozilla::IsSame<class, class ::Has_NS_DECL_QUERYFRAME_TARGET>::value, \
-        #class " must declare itself as a queryframe target");                \
-    return const_cast<class*>(static_cast<const class*>(this));               \
+#define NS_QUERYFRAME_ENTRY(class)                                    \
+  case class ::kFrameIID: {                                           \
+    static_assert(                                                    \
+        std::is_same_v<class, class ::Has_NS_DECL_QUERYFRAME_TARGET>, \
+        #class " must declare itself as a queryframe target");        \
+    return const_cast<class*>(static_cast<const class*>(this));       \
   }
 
-#define NS_QUERYFRAME_ENTRY_CONDITIONAL(class, condition)                \
-  case class ::kFrameIID:                                                \
-    if (condition) {                                                     \
-      static_assert(                                                     \
-          mozilla::IsSame<class,                                         \
-                          class ::Has_NS_DECL_QUERYFRAME_TARGET>::value, \
-          #class " must declare itself as a queryframe target");         \
-      return const_cast<class*>(static_cast<const class*>(this));        \
-    }                                                                    \
+#define NS_QUERYFRAME_ENTRY_CONDITIONAL(class, condition)               \
+  case class ::kFrameIID:                                               \
+    if (condition) {                                                    \
+      static_assert(                                                    \
+          std::is_same_v<class, class ::Has_NS_DECL_QUERYFRAME_TARGET>, \
+          #class " must declare itself as a queryframe target");        \
+      return const_cast<class*>(static_cast<const class*>(this));       \
+    }                                                                   \
     break;
 
 #define NS_QUERYFRAME_TAIL_INHERITING(class) \
@@ -99,10 +98,9 @@ class do_QueryFrameHelper {
 
   template <class Dest>
   operator Dest*() {
-    static_assert(
-        mozilla::IsSame<std::remove_const_t<Dest>,
-                        typename Dest::Has_NS_DECL_QUERYFRAME_TARGET>::value,
-        "Dest must declare itself as a queryframe target");
+    static_assert(std::is_same_v<std::remove_const_t<Dest>,
+                                 typename Dest::Has_NS_DECL_QUERYFRAME_TARGET>,
+                  "Dest must declare itself as a queryframe target");
     if (!mRawPtr) {
       return nullptr;
     }
diff --git a/mfbt/TypeTraits.h b/mfbt/TypeTraits.h
index 8bd5ad2b7d94..de4c93cba073 100644
--- a/mfbt/TypeTraits.h
+++ b/mfbt/TypeTraits.h
@@ -102,26 +102,6 @@ struct IsDestructibleImpl : public DoIsDestructibleImpl {
 template <typename T>
 struct IsDestructible : public detail::IsDestructibleImpl<T>::Type {};
 
-/* 20.9.5 Type property queries [meta.unary.prop.query] */
-
-/* 20.9.6 Relationships between types [meta.rel] */
-
-/**
- * IsSame tests whether two types are the same type.
- *
- * mozilla::IsSame<int, int>::value is true;
- * mozilla::IsSame<int*, int*>::value is true;
- * mozilla::IsSame<int, unsigned int>::value is false;
- * mozilla::IsSame<void, void>::value is true;
- * mozilla::IsSame<const int, int>::value is false;
- * mozilla::IsSame<struct S, struct S>::value is true.
- */
-template <typename T, typename U>
-struct IsSame : std::false_type {};
-
-template <typename T>
-struct IsSame<T, T> : std::true_type {};
-
 } /* namespace mozilla */
 
 #endif /* mozilla_TypeTraits_h */
diff --git a/mfbt/tests/TestTypeTraits.cpp b/mfbt/tests/TestTypeTraits.cpp
index 9e811a6a05c5..4e945c7a8aed 100644
--- a/mfbt/tests/TestTypeTraits.cpp
+++ b/mfbt/tests/TestTypeTraits.cpp
@@ -4,11 +4,12 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#include <type_traits>
+
 #include "mozilla/Assertions.h"
 #include "mozilla/TypeTraits.h"
 
 using mozilla::IsDestructible;
-using mozilla::IsSame;
 
 class PublicDestructible {
  public:
@@ -35,9 +36,9 @@ static_assert(IsDestructible<TrivialDestructible>::value,
  * actual type sizes seen at compile time.
  */
 #if defined(ANDROID) && !defined(__LP64__)
-static_assert(mozilla::IsSame<int, intptr_t>::value,
+static_assert(std::is_same_v<int, intptr_t>,
               "emulated PRI[di]PTR definitions will be wrong");
-static_assert(mozilla::IsSame<unsigned int, uintptr_t>::value,
+static_assert(std::is_same_v<unsigned int, uintptr_t>,
               "emulated PRI[ouxX]PTR definitions will be wrong");
 #endif
 
diff --git a/mozglue/baseprofiler/core/ProfileBufferEntry.cpp b/mozglue/baseprofiler/core/ProfileBufferEntry.cpp
index d7191bcf779f..abbb06cee189 100644
--- a/mozglue/baseprofiler/core/ProfileBufferEntry.cpp
+++ b/mozglue/baseprofiler/core/ProfileBufferEntry.cpp
@@ -19,6 +19,7 @@
 #  include "mozilla/StackWalk.h"
 
 #  include <ostream>
+#  include <type_traits>
 
 namespace mozilla {
 namespace baseprofiler {
@@ -152,7 +153,7 @@ class MOZ_RAII AutoArraySchemaWriter {
 
   template <typename T>
   void IntElement(uint32_t aIndex, T aValue) {
-    static_assert(!IsSame<T, uint64_t>::value,
+    static_assert(!std::is_same_v<T, uint64_t>,
                   "Narrowing uint64 -> int64 conversion not allowed");
     FillUpTo(aIndex);
     mJSONWriter.IntElement(static_cast<int64_t>(aValue));
diff --git a/tools/profiler/core/ProfileBufferEntry.cpp b/tools/profiler/core/ProfileBufferEntry.cpp
index 2cb6b15cd14f..975152a7cc4b 100644
--- a/tools/profiler/core/ProfileBufferEntry.cpp
+++ b/tools/profiler/core/ProfileBufferEntry.cpp
@@ -20,6 +20,7 @@
 #include "ProfilerCodeAddressService.h"
 
 #include <ostream>
+#include <type_traits>
 
 using namespace mozilla;
 
@@ -161,7 +162,7 @@ class MOZ_RAII AutoArraySchemaWriter {
 
   template <typename T>
   void IntElement(uint32_t aIndex, T aValue) {
-    static_assert(!IsSame<T, uint64_t>::value,
+    static_assert(!std::is_same_v<T, uint64_t>,
                   "Narrowing uint64 -> int64 conversion not allowed");
     FillUpTo(aIndex);
     mJSONWriter.IntElement(static_cast<int64_t>(aValue));
diff --git a/tools/profiler/core/platform.cpp b/tools/profiler/core/platform.cpp
index e9421e648f84..630716a07e38 100644
--- a/tools/profiler/core/platform.cpp
+++ b/tools/profiler/core/platform.cpp
@@ -84,6 +84,7 @@
 #include <fstream>
 #include <ostream>
 #include <sstream>
+#include <type_traits>
 
 #ifdef MOZ_TASK_TRACER
 #  include "GeckoTaskTracer.h"
@@ -2790,8 +2791,8 @@ class SamplerThread {
     // It may be tempting for a future maintainer to change aCallbacks into an
     // rvalue reference; this will remind them not to do that!
     static_assert(
-        IsSame<decltype(aCallbacks),
-               UniquePtr<PostSamplingCallbackListItem>>::value,
+        std::is_same_v<decltype(aCallbacks),
+                       UniquePtr<PostSamplingCallbackListItem>>,
         "We need to capture the list by-value, to implicitly destroy it");
   }