[clang-tidy] Adding Fuchsia checker for trailing returns

Adds a check to the Fuchsia module to warn if a function has a trailing
return.

See https://fuchsia.googlesource.com/zircon/+/master/docs/cxx.md for
reference.

Differential Revision: https://reviews.llvm.org/D42116

llvm-svn: 322759

1 files changed, 23 insertions, 0 deletions

diff --git a/clang-tools-extra/test/clang-tidy/fuchsia-trailing-return.cpp b/clang-tools-extra/test/clang-tidy/fuchsia-trailing-return.cpp
new file mode 100644
index 00000000000..f6c943ac873
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/fuchsia-trailing-return.cpp
@@ -0,0 +1,23 @@
+// RUN: %check_clang_tidy %s fuchsia-trailing-return %t
+
+int add_one(const int arg) { return arg; }
+
+auto get_add_one() -> int (*)(const int) {
+  // CHECK-MESSAGES: [[@LINE-1]]:1: warning: a trailing return type is disallowed for this type of declaration
+  // CHECK-NEXT: auto get_add_one() -> int (*)(const int) {
+  return add_one;
+}
+
+auto lambda = [](double x, double y) {return x + y;};
+
+auto lambda2 = [](double x, double y) -> double {return x + y;};
+
+int main() {
+  get_add_one()(5);
+  return 0;
+}
+
+template <typename T1, typename T2>
+auto fn(const T1 &lhs, const T2 &rhs) -> decltype(lhs + rhs) {
+  return lhs + rhs;
+}