[clang-format] [PR42417] clang-format inserts a space after '->' for operator->() overloading

Summary:
https://bugs.llvm.org/show_bug.cgi?id=42417

This revision removes the extra space between the opertor-> and the parens ()

```
class Bug {
    auto operator-> () -> int*;
    auto operator++(int) -> int;
};
```

Reviewers: klimek, owenpan, byoungyoung, mitchell-stellar

Reviewed By: mitchell-stellar

Subscribers: cfe-commits

Tags: #clang-format, #clang

Differential Revision: https://reviews.llvm.org/D68242

llvm-svn: 373746

2 files changed, 7 insertions, 1 deletions

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index e6dfffd9733..50e3d056b83 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -1393,7 +1393,9 @@ private:
                Style.Language == FormatStyle::LK_Java) {
       Current.Type = TT_LambdaArrow;
     } else if (Current.is(tok::arrow) && AutoFound && Line.MustBeDeclaration &&
-               Current.NestingLevel == 0) {
+               Current.NestingLevel == 0 &&
+               !Current.Previous->is(tok::kw_operator)) {
+      // not auto operator->() -> xxx;
       Current.Type = TT_TrailingReturnArrow;
       TrailingReturnFound = true;
     } else if (Current.is(tok::star) ||
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index e982c8b2ab0..b770d0f26f8 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -4956,6 +4956,10 @@ TEST_F(FormatTest, DontBreakBeforeQualifiedOperator) {
 
 TEST_F(FormatTest, TrailingReturnType) {
   verifyFormat("auto foo() -> int;\n");
+  // correct trailing return type spacing
+  verifyFormat("auto operator->() -> int;\n");
+  verifyFormat("auto operator++(int) -> int;\n");
+
   verifyFormat("struct S {\n"
                "  auto bar() const -> int;\n"
                "};");