[clang-tidy] Improve bugprone-unused-return-value check

Summary:
Add support for checking class template member functions.

Also add the following functions to be checked by default:

- std::unique_ptr::release
- std::basic_string::empty
- std::vector::empty

Reviewers: alexfh, hokein, aaron.ballman, ilya-biryukov

Reviewed By: aaron.ballman

Subscribers: jbcoe, xazax.hun, cfe-commits

Tags: #clang-tools-extra

Differential Revision: https://reviews.llvm.org/D45891

Patch by khuttun (Kalle Huttunen)

llvm-svn: 330772

1 files changed, 21 insertions, 3 deletions

diff --git a/clang-tools-extra/test/clang-tidy/bugprone-unused-return-value-custom.cpp b/clang-tools-extra/test/clang-tidy/bugprone-unused-return-value-custom.cpp
index 4f498ddcc37..efe3705e3be 100644
--- a/clang-tools-extra/test/clang-tidy/bugprone-unused-return-value-custom.cpp
+++ b/clang-tools-extra/test/clang-tidy/bugprone-unused-return-value-custom.cpp
@@ -1,7 +1,7 @@
 // RUN: %check_clang_tidy %s bugprone-unused-return-value %t \
 // RUN: -config='{CheckOptions: \
 // RUN:  [{key: bugprone-unused-return-value.CheckedFunctions, \
-// RUN:    value: "::fun;::ns::Outer::Inner::memFun;::ns::Type::staticFun"}]}' \
+// RUN:    value: "::fun;::ns::Outer::Inner::memFun;::ns::Type::staticFun;::ns::ClassTemplate::memFun;::ns::ClassTemplate::staticFun"}]}' \
 // RUN: --
 
 namespace std {
@@ -34,6 +34,12 @@ struct Type {
   static Retval staticFun();
 };
 
+template <typename T>
+struct ClassTemplate {
+  Retval memFun();
+  static Retval staticFun();
+};
+
 } // namespace ns
 
 int fun();
@@ -60,6 +66,13 @@ void warning() {
 
   ns::Type::staticFun();
   // CHECK-MESSAGES: [[@LINE-1]]:3: warning: the value returned by this function should be used [bugprone-unused-return-value]
+
+  ns::ClassTemplate<int> ObjA4;
+  ObjA4.memFun();
+  // CHECK-MESSAGES: [[@LINE-1]]:3: warning: the value returned by this function should be used [bugprone-unused-return-value]
+
+  ns::ClassTemplate<int>::staticFun();
+  // CHECK-MESSAGES: [[@LINE-1]]:3: warning: the value returned by this function should be used [bugprone-unused-return-value]
 }
 
 void noWarning() {
@@ -70,6 +83,11 @@ void noWarning() {
 
   auto R3 = ns::Type::staticFun();
 
+  ns::ClassTemplate<int> ObjB2;
+  auto R4 = ObjB2.memFun();
+
+  auto R5 = ns::ClassTemplate<int>::staticFun();
+
   // test calling a void overload of a checked function
   fun(5);
 
@@ -77,6 +95,6 @@ void noWarning() {
   int I = 1;
   std::launder(&I);
 
-  ns::Type ObjB2;
-  ObjB2.memFun();
+  ns::Type ObjB3;
+  ObjB3.memFun();
 }