Add test for r288732, warn on unsigned zero in std::max

llvm-svn: 288740

diff --git a/clang/test/SemaCXX/warn-max-unsigned-zero.cpp b/clang/test/SemaCXX/warn-max-unsigned-zero.cpp
new file mode 100644 (file)
index 0000000..5564b10
--- /dev/null
+++ b/clang/test/SemaCXX/warn-max-unsigned-zero.cpp
@@ -0,0 +1,55 @@
+// RUN: %clang_cc1 -fsyntax-only -Wmax-unsigned-zero -verify %s -std=c++11
+// RUN: %clang_cc1 -fsyntax-only -Wmax-unsigned-zero %s -std=c++11 -fdiagnostics-parseable-fixits 2>&1 | FileCheck %s
+
+namespace std {
+template <typename T>
+T max(const T &, const T &);
+}
+
+void test(unsigned u) {
+  auto a = std::max(55u, 0u);
+  // expected-warning@-1{{taking the max of a value and unsigned zero is always equal to the other value}}
+  // expected-note@-2{{remove call to max function and unsigned zero argument}}
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:12-[[@LINE-3]]:20}:""
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:24-[[@LINE-4]]:28}:""
+  auto b = std::max(u, 0u);
+  // expected-warning@-1{{taking the max of a value and unsigned zero is always equal to the other value}}
+  // expected-note@-2{{remove call to max function and unsigned zero argument}}
+  // fix-it:"/usr/local/google/home/rtrieu/clang/open/llvm/tools/clang/test/SemaCXX/warn-max-unsigned-zero.cpp":{13:12-13:20}:""
+  // fix-it:"/usr/local/google/home/rtrieu/clang/open/llvm/tools/clang/test/SemaCXX/warn-max-unsigned-zero.cpp":{13:22-13:26}:""
+  auto c = std::max(0u, 55u);
+  // expected-warning@-1{{taking the max of unsigned zero and a value is always equal to the other value}}
+  // expected-note@-2{{remove call to max function and unsigned zero argument}}
+  // fix-it:"/usr/local/google/home/rtrieu/clang/open/llvm/tools/clang/test/SemaCXX/warn-max-unsigned-zero.cpp":{16:12-16:20}:""
+  // fix-it:"/usr/local/google/home/rtrieu/clang/open/llvm/tools/clang/test/SemaCXX/warn-max-unsigned-zero.cpp":{16:21-16:24}:""
+  auto d = std::max(0u, u);
+  // expected-warning@-1{{taking the max of unsigned zero and a value is always equal to the other value}}
+  // expected-note@-2{{remove call to max function and unsigned zero argument}}
+  // fix-it:"/usr/local/google/home/rtrieu/clang/open/llvm/tools/clang/test/SemaCXX/warn-max-unsigned-zero.cpp":{19:12-19:20}:""
+  // fix-it:"/usr/local/google/home/rtrieu/clang/open/llvm/tools/clang/test/SemaCXX/warn-max-unsigned-zero.cpp":{19:21-19:24}:""
+}
+
+void negative_test(signed s) {
+  auto a = std::max(0, s);
+  auto b = std::max(s, 0);
+  auto c = std::max(22, 0);
+  auto d = std::max(0, 22);
+}
+
+template <unsigned x>
+unsigned template_test() {
+  return std::max(x, 0u);
+  // expected-warning@-1{{taking the max of a value and unsigned zero is always equal to the other value}}
+  // expected-note@-2{{remove call to max function and unsigned zero argument}}
+  // fix-it:"/usr/local/google/home/rtrieu/clang/open/llvm/tools/clang/test/SemaCXX/warn-max-unsigned-zero.cpp":{33:10-33:18}:""
+  // fix-it:"/usr/local/google/home/rtrieu/clang/open/llvm/tools/clang/test/SemaCXX/warn-max-unsigned-zero.cpp":{33:20-33:24}:""
+}
+
+int a = template_test<0>() + template_test<1>() + template_test<2>();
+
+#define comp(x,y) std::max(x, y)
+
+int b = comp(0, 1);
+int c = comp(0u, 1u);
+int d = comp(2u, 0u);
+