diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/dangling-handle.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/dangling-handle.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/dangling-handle.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/dangling-handle.cpp
@@ -2,7 +2,7 @@
 // RUN:   -config="{CheckOptions: \
 // RUN:             [{key: bugprone-dangling-handle.HandleClasses, \
 // RUN:               value: 'std::basic_string_view; ::llvm::StringRef;'}]}"
-// FIXME: Fix the checker to work in C++17 mode.
+// FIXME: Fix the checker to work in C++17 or later mode.
 
 namespace std {
 
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/easily-swappable-parameters-implicits.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/easily-swappable-parameters-implicits.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/easily-swappable-parameters-implicits.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/easily-swappable-parameters-implicits.cpp
@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy -std=c++17 %s bugprone-easily-swappable-parameters %t \
+// RUN: %check_clang_tidy -std=c++17-or-later %s bugprone-easily-swappable-parameters %t \
 // RUN:   -config='{CheckOptions: [ \
 // RUN:     {key: bugprone-easily-swappable-parameters.MinimumLength, value: 2}, \
 // RUN:     {key: bugprone-easily-swappable-parameters.IgnoredParameterNames, value: ""}, \
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/exception-escape.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/exception-escape.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/exception-escape.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/exception-escape.cpp
@@ -4,6 +4,7 @@
 // RUN:         {key: bugprone-exception-escape.FunctionsThatShouldNotThrow, value: 'enabled1,enabled2,enabled3'} \
 // RUN:     ]}" \
 // RUN:     -- -fexceptions
+// FIXME: Fix the checker to work in C++17 or later mode.
 
 struct throwing_destructor {
   ~throwing_destructor() {
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/signal-handler.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/signal-handler.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/signal-handler.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/signal-handler.cpp
@@ -1,5 +1,5 @@
 // RUN: %check_clang_tidy -std=c++14 %s bugprone-signal-handler %t -- -- -isystem %clang_tidy_headers -isystem %S/Inputs/signal-handler -target x86_64-unknown-unknown
-
+// FIXME: Fix the checker to work in C++17 or later mode.
 #include "stdcpp.h"
 #include "stdio.h"
 
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/unhandled-exception-at-new.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/unhandled-exception-at-new.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/unhandled-exception-at-new.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/unhandled-exception-at-new.cpp
@@ -1,5 +1,5 @@
 // RUN: %check_clang_tidy -std=c++14 %s bugprone-unhandled-exception-at-new %t -- -- -fexceptions
-
+// FIXME: Fix the checker to work in C++17 or later mode.
 namespace std {
 typedef __typeof__(sizeof(0)) size_t;
 enum class align_val_t : std::size_t {};
diff --git a/clang-tools-extra/test/clang-tidy/checkers/cert/throw-exception-type.cpp b/clang-tools-extra/test/clang-tidy/checkers/cert/throw-exception-type.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/cert/throw-exception-type.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cert/throw-exception-type.cpp
@@ -1,7 +1,7 @@
 // RUN: %check_clang_tidy -std=c++11,c++14 %s cert-err60-cpp %t -- -- -fcxx-exceptions
 // FIXME: Split off parts of this test that rely on dynamic exception
 // specifications, and run this test in all language modes.
-
+// FIXME: Fix the checker to work in C++17 or later mode.
 struct S {};
 struct T : S {};
 struct U {
diff --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-member-init-cxx98.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-member-init-cxx98.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-member-init-cxx98.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-member-init-cxx98.cpp
@@ -1,5 +1,4 @@
 // RUN: %check_clang_tidy -std=c++98 %s cppcoreguidelines-pro-type-member-init %t -- -- -fno-delayed-template-parsing
-
 struct PositiveFieldBeforeConstructor {
   int F;
   PositiveFieldBeforeConstructor() /* some comment */ {}
diff --git a/clang-tools-extra/test/clang-tidy/checkers/misc/static-assert.cpp b/clang-tools-extra/test/clang-tidy/checkers/misc/static-assert.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/misc/static-assert.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/misc/static-assert.cpp
@@ -1,5 +1,5 @@
 // RUN: %check_clang_tidy -std=c++11 -check-suffixes=,CXX11 %s misc-static-assert %t
-// RUN: %check_clang_tidy -std=c++17 -check-suffixes=,CXX17 %s misc-static-assert %t
+// RUN: %check_clang_tidy -std=c++17-or-later -check-suffixes=,CXX17 %s misc-static-assert %t
 
 void abort() {}
 #ifdef NDEBUG
diff --git a/clang-tools-extra/test/clang-tidy/checkers/performance/unnecessary-copy-initialization.cpp b/clang-tools-extra/test/clang-tidy/checkers/performance/unnecessary-copy-initialization.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/performance/unnecessary-copy-initialization.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/performance/unnecessary-copy-initialization.cpp
@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy -std=c++17 %s performance-unnecessary-copy-initialization %t
+// RUN: %check_clang_tidy -std=c++17-or-later %s performance-unnecessary-copy-initialization %t
 
 template <typename T>
 struct Iterator {
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/const-return-type-macros.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/const-return-type-macros.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/const-return-type-macros.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/const-return-type-macros.cpp
@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy -std=c++14 %s readability-const-return-type %t -- \
+// RUN: %check_clang_tidy -std=c++14-or-later %s readability-const-return-type %t -- \
 // RUN:   -config="{CheckOptions: [{key: readability-const-return-type.IgnoreMacros, value: false}]}"
 
 //  p# = positive test
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/const-return-type.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/const-return-type.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/const-return-type.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/const-return-type.cpp
@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy -std=c++14 %s readability-const-return-type %t
+// RUN: %check_clang_tidy -std=c++14-or-later %s readability-const-return-type %t
 
 //  p# = positive test
 //  n# = negative test
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/isolate-declaration-cxx17.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/isolate-declaration-cxx17.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/isolate-declaration-cxx17.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/isolate-declaration-cxx17.cpp
@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy -std=c++17 %s readability-isolate-declaration %t
+// RUN: %check_clang_tidy -std=c++17-or-later %s readability-isolate-declaration %t
 
 template <typename T1, typename T2>
 struct pair {
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/use-anyofallof.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/use-anyofallof.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/use-anyofallof.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/use-anyofallof.cpp
@@ -1,4 +1,5 @@
 // RUN: %check_clang_tidy -std=c++14,c++17 %s readability-use-anyofallof %t -- -- -fexceptions
+// FIXME: Fix the checker to work in C++20 mode.
 
 bool good_any_of() {
   int v[] = {1, 2, 3};
diff --git a/clang-tools-extra/unittests/clang-tidy/ClangTidyTest.h b/clang-tools-extra/unittests/clang-tidy/ClangTidyTest.h
--- a/clang-tools-extra/unittests/clang-tidy/ClangTidyTest.h
+++ b/clang-tools-extra/unittests/clang-tidy/ClangTidyTest.h
@@ -110,7 +110,7 @@
     Args.push_back("-fobjc-arc");
   }
   if (extension == ".cc" || extension == ".cpp" || extension == ".mm") {
-    Args.push_back("-std=c++11");
+    Args.push_back("-std=c++20");
   }
   Args.push_back("-Iinclude");
   Args.insert(Args.end(), ExtraArgs.begin(), ExtraArgs.end());