1 files changed, 46 insertions, 0 deletions
diff --git a/test/SemaCXX/warn-unused-result.cpp b/test/SemaCXX/warn-unused-result.cpp
index 01bc457ec206..88f5ab1e85c0 100644
--- a/test/SemaCXX/warn-unused-result.cpp
+++ b/test/SemaCXX/warn-unused-result.cpp
@@ -160,3 +160,49 @@ void g() {
   (void)noexcept(f(), false); // Should not warn.
 }
 }
+
+namespace {
+// C++ Methods should warn even in their own class.
+struct [[clang::warn_unused_result]] S {
+  S DoThing() { return {}; };
+  S operator++(int) { return {}; };
+  S operator--(int) { return {}; };
+  // Improperly written prefix.
+  S operator++() { return {}; };
+  S operator--() { return {}; };
+};
+
+struct [[clang::warn_unused_result]] P {
+  P DoThing() { return {}; };
+};
+
+P operator++(const P &, int) { return {}; };
+P operator--(const P &, int) { return {}; };
+// Improperly written prefix.
+P operator++(const P &) { return {}; };
+P operator--(const P &) { return {}; };
+
+void f() {
+  S s;
+  P p;
+  s.DoThing(); // expected-warning {{ignoring return value}}
+  p.DoThing(); // expected-warning {{ignoring return value}}
+  // Only postfix is expected to warn when written correctly.
+  s++; // expected-warning {{ignoring return value}}
+  s--; // expected-warning {{ignoring return value}}
+  p++; // expected-warning {{ignoring return value}}
+  p--; // expected-warning {{ignoring return value}}
+  // Improperly written prefix operators should still warn.
+  ++s; // expected-warning {{ignoring return value}}
+  --s; // expected-warning {{ignoring return value}}
+  ++p; // expected-warning {{ignoring return value}}
+  --p; // expected-warning {{ignoring return value}}
+
+  // Silencing the warning by cast to void still works.
+  (void)s.DoThing();
+  (void)s++;
+  (void)p++;
+  (void)++s;
+  (void)++p;
+}
+} // namespace