[clang-tools-extra] [clang-tidy] add check to suggest replacement of nested std::min or std::max with initializer lists (PR #85572)

[Piotr Zegar via cfe-commits]

================
@@ -0,0 +1,105 @@
+// RUN: %check_clang_tidy %s modernize-min-max-use-initializer-list %t
+
+// CHECK-FIXES: #include <algorithm>
+namespace std {
+template< class T >
+const T& max( const T& a, const T& b ) {
+  return (a < b) ? b : a;
+};
+
+template< class T, class Compare >
+const T& max( const T& a, const T& b, Compare comp ) {
+  return (comp(a, b)) ? b : a;
+};
+
+template< class T >
+const T& min( const T& a, const T& b ) {
+  return (b < a) ? b : a;
+};
+
+template< class T, class Compare >
+const T& min( const T& a, const T& b, Compare comp ) {
+  return (comp(b, a)) ? b : a;
+};
+}
+
+using namespace std;
+
+namespace {
+bool fless_than(int a, int b) {
+return a < b;
+}
+
+bool fgreater_than(int a, int b) {
+return a > b;
+}
+auto less_than = [](int a, int b) { return a < b; };
+auto greater_than = [](int a, int b) { return a > b; };
+
+int max1 = std::max(1, std::max(2, 3));
+// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: do not use nested std::max calls, use std::max({1, 2, 3}) instead [modernize-min-max-use-initializer-list]
+// CHECK-FIXES: int max1 = std::max({1, 2, 3});
+
+int min1 = std::min(1, std::min(2, 3));
+// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: do not use nested std::min calls, use std::min({1, 2, 3}) instead [modernize-min-max-use-initializer-list]
+// CHECK-FIXES: int min1 = std::min({1, 2, 3});
+
+int max2 = std::max(1, std::max(2, std::max(3, 4)));
+// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: do not use nested std::max calls, use std::max({1, 2, 3, 4}) instead [modernize-min-max-use-initializer-list]
+// CHECK-FIXES: int max2 = std::max({1, 2, 3, 4});
+
+int min2 = std::min(1, std::min(2, std::min(3, 4)));
+// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: do not use nested std::min calls, use std::min({1, 2, 3, 4}) instead [modernize-min-max-use-initializer-list]
+// CHECK-FIXES: int min2 = std::min({1, 2, 3, 4});
+
+int max3 = std::max(std::max(4, 5), std::min(2, std::min(3, 1)));
+// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: do not use nested std::max calls, use std::max({4, 5, std::min({2, 3, 1})}) instead [modernize-min-max-use-initializer-list]
+// CHECK-MESSAGES: :[[@LINE-2]]:37: warning: do not use nested std::min calls, use std::min({2, 3, 1}) instead [modernize-min-max-use-initializer-list]
+// CHECK-FIXES: int max3 = std::max({4, 5, std::min({2, 3, 1})});
+
+int min3 = std::min(std::min(4, 5), std::max(2, std::max(3, 1)));
+// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: do not use nested std::min calls, use std::min({4, 5, std::max({2, 3, 1})}) instead [modernize-min-max-use-initializer-list]
+// CHECK-MESSAGES: :[[@LINE-2]]:37: warning: do not use nested std::max calls, use std::max({2, 3, 1}) instead [modernize-min-max-use-initializer-list]
+// CHECK-FIXES: int min3 = std::min({4, 5, std::max({2, 3, 1})});
+
----------------
PiotrZSL wrote:

add:
```
std::min(std::min(4, 5), std::max(2, utils::max(3, 1)));
```

https://github.com/llvm/llvm-project/pull/85572