1 files changed, 56 insertions, 0 deletions
diff --git a/clang-tools-extra/clang-tidy/fuchsia/TrailingReturnCheck.cpp b/clang-tools-extra/clang-tidy/fuchsia/TrailingReturnCheck.cpp
new file mode 100644
index 00000000000..27989d9bba1
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/fuchsia/TrailingReturnCheck.cpp
@@ -0,0 +1,56 @@
+//===--- TrailingReturnCheck.cpp - clang-tidy------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "TrailingReturnCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchersInternal.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace ast_matchers {
+
+const internal::VariadicDynCastAllOfMatcher<Type, DecltypeType> decltypeType;
+
+} // namespace ast_matchers
+
+namespace tidy {
+namespace fuchsia {
+
+AST_MATCHER(FunctionDecl, hasTrailingReturn) {
+  return Node.getType()->castAs<FunctionProtoType>()->hasTrailingReturn();
+}
+
+void TrailingReturnCheck::registerMatchers(MatchFinder *Finder) {
+
+  // Requires C++11 or later.
+  if (!getLangOpts().CPlusPlus11)
+    return;
+
+  // Functions that have trailing returns are disallowed, except for those
+  // using decltype specifiers and lambda with otherwise unutterable
+  // return types.
+  Finder->addMatcher(
+      functionDecl(allOf(hasTrailingReturn(),
+                         unless(anyOf(returns(decltypeType()),
+                                      hasParent(cxxRecordDecl(isLambda()))))))
+          .bind("decl"),
+      this);
+}
+
+void TrailingReturnCheck::check(const MatchFinder::MatchResult &Result) {
+  if (const auto *D = Result.Nodes.getNodeAs<Decl>("decl"))
+    diag(D->getLocStart(),
+         "a trailing return type is disallowed for this type of declaration");
+}
+
+} // namespace fuchsia
+} // namespace tidy
+} // namespace clang