[clang-tidy] Update tests to include C++23 and C++26

[avogelsgesang]

Summary

This commit changes the c++xx-or-later definitions to also include
C++23 and the upcoming C++26.
readability/container-contains.cpp to also test newer C++ versions.

Also, this commit adjusts a couple of test cases slightly:

• container-contains.cpp now also tests newer C++ versions. Restricting it to C++20 was an oversight of mine when originally writing this check.
• unconventional-assign-operator.cpp: The return rhs raised a "non-const lvalue reference to type 'BadReturnStatement' cannot bind to a temporary" error in C++23. The issue is circumenvented by writing return *&rhs.
• const-correctness-values.cpp was also running into the same error in C++23. The troublesome test cases were moved to a separate file.

[PiotrZSL]

LGTM

[PiotrZSL]

clang-tools-extra/test/clang-tidy/checkers/misc/const-correctness-values-before-cxx23.cpp

3–7

[avogelsgesang]

Address comments

clang-tools-extra/test/clang-tidy/check_clang_tidy.py

def run(self):
         clang_tidy_output = self.run_clang_tidy()
         self.check_fixes()
         self.check_messages(clang_tidy_output)
         self.check_notes(clang_tidy_output)
 
 
 def expand_std(std):
     if std == "c++98-or-later":
-        return ["c++98", "c++11", "c++14", "c++17", "c++20"]
+        return ["c++98", "c++11", "c++14", "c++17", "c++20", "c++23", "c++2c"]
     if std == "c++11-or-later":
-        return ["c++11", "c++14", "c++17", "c++20"]
+        return ["c++11", "c++14", "c++17", "c++20", "c++23", "c++2c"]
     if std == "c++14-or-later":
-        return ["c++14", "c++17", "c++20"]
+        return ["c++14", "c++17", "c++20", "c++23", "c++2c"]
     if std == "c++17-or-later":
-        return ["c++17", "c++20"]
+        return ["c++17", "c++20", "c++23", "c++2c"]
     if std == "c++20-or-later":
-        return ["c++20"]
+        return ["c++20", "c++23", "c++2c"]
+    if std == "c++23-or-later":
+        return ["c++23", "c++2c"]
     return [std]
 
 
 def csv(string):
     return string.split(",")
 
 
 def parse_arguments():

clang-tools-extra/test/clang-tidy/checkers/misc/const-correctness-values-before-cxx23.cpp

+// RUN: %check_clang_tidy -std=c++11,c++14,c++17,c++20 %s misc-const-correctness %t -- \
+// RUN:   -config="{CheckOptions: {\
+// RUN:     misc-const-correctness.TransformValues: true, \
+// RUN:     misc-const-correctness.WarnPointersAsValues: false, \
+// RUN:     misc-const-correctness.TransformPointersAsValues: false \
+// RUN:   }}" -- -fno-delayed-template-parsing
+
+
+double &non_const_ref_return() {
+  double p_local0 = 0.0;
+  // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'double' can be declared 'const'
+  // CHECK-FIXES: double const p_local0
+  double np_local0 = 42.42;
+  return np_local0;
+}
+
+double *&return_non_const_pointer_ref() {
+  double *np_local0 = nullptr;
+  return np_local0;
+}

clang-tools-extra/test/clang-tidy/checkers/misc/const-correctness-values.cpp

 // RUN: %check_clang_tidy %s misc-const-correctness %t -- \
 // RUN:   -config="{CheckOptions: {\
-// RUN:   misc-const-correctness.TransformValues: true, \
-// RUN:   misc-const-correctness.WarnPointersAsValues: false, \
-// RUN:   misc-const-correctness.TransformPointersAsValues: false} \
-// RUN:   }" -- -fno-delayed-template-parsing
+// RUN:     misc-const-correctness.TransformValues: true, \
+// RUN:     misc-const-correctness.WarnPointersAsValues: false, \
+// RUN:     misc-const-correctness.TransformPointersAsValues: false \
+// RUN:   }}" -- -fno-delayed-template-parsing
 
 // ------- Provide test samples for primitive builtins ---------
 // - every 'p_*' variable is a 'potential_const_*' variable
 // - every 'np_*' variable is a 'non_potential_const_*' variable
 
 bool global;
 char np_global = 0; // globals can't be known to be const
 
const double *const_pointer_return() {
   // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'double' can be declared 'const'
   // CHECK-FIXES: double const p_local0
   double p_local1 = 24.4;
   // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'double' can be declared 'const'
   // CHECK-FIXES: double const p_local1
   return &p_local1;
 }
 
-double &non_const_ref_return() {
-  double p_local0 = 0.0;
-  // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'double' can be declared 'const'
-  // CHECK-FIXES: double const p_local0
-  double np_local0 = 42.42;
-  return np_local0;
-}
-
+// Also see const-correctness-values.cpp-before-cxx23.cpp for `non_const_ref_return` and `return_non_const_pointer_ref`
 const double &const_ref_return() {
   double p_local0 = 0.0;
   // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'double' can be declared 'const'
   // CHECK-FIXES: double const p_local0
   double p_local1 = 24.4;
   // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'double' can be declared 'const'
   // CHECK-FIXES: double const p_local1
   return p_local1;
 }
 
-double *&return_non_const_pointer_ref() {
-  double *np_local0 = nullptr;
-  return np_local0;
-}
-
 void overloaded_arguments(const int &in);
 void overloaded_arguments(int &inout);
 void overloaded_arguments(const int *in);
 void overloaded_arguments(int *inout);
 
 void function_calling() {
   int np_local0 = 42;
   overloaded_arguments(np_local0);

clang-tools-extra/test/clang-tidy/checkers/misc/unconventional-assign-operator.cpp

struct BadReturnType2 {
   int operator=(BadReturnType2&&);
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: operator=() should return 'Bad
 };
 
 struct BadArgument {
   BadArgument& operator=(BadArgument&);
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: operator=() should take 'BadArgument const&', 'BadArgument&&' or 'BadArgument'
   BadArgument& operator=(const BadArgument&&);
-  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: operator=() should take 'BadAr
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: operator=() should take 'BadArgument const&', 'BadArgument&&' or 'BadArgument'
 };
 
 struct BadModifier {
   BadModifier& operator=(const BadModifier&) const;
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: operator=() should not be marked 'const'
 };
 
 struct Deleted {

 };
 
 class BadReturnStatement {
   int n;
 
 public:
   BadReturnStatement& operator=(BadReturnStatement&& rhs) {
     n = std::move(rhs.n);
-    return rhs;
+    return *&rhs;
 // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: operator=() should always return '*this'
   }
 
   // Do not check if return type is different from '&BadReturnStatement'
   int operator=(int i) {
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: operator=() should return 'Bad
     n = i;
     return n;

clang-tools-extra/test/clang-tidy/checkers/readability/container-contains.cpp

-// RUN: %check_clang_tidy -std=c++20 %s readability-container-contains %t
+// RUN: %check_clang_tidy -std=c++20-or-later %s readability-container-contains %t
 
 // Some *very* simplified versions of `map` etc.
 namespace std {
 
 template <class Key, class T>
 struct map {
   unsigned count(const Key &K) const;
   bool contains(const Key &K) const;