[clang-format][PR41899] PointerAlignment: Left leads to useless space in lambda intializer expression

Summary:
https://bugs.llvm.org/show_bug.cgi?id=41899

```auto lambda = [&a = a]() { a = 2; };```

is formatted as

```auto lambda = [& a = a]() { a = 2; };```

With an extra space if PointerAlignment is set to Left

> The space "& a" looks strange when there is no type in the lambda's intializer expression. This can be worked around with by setting "PointerAlignment: Right", but ideally "PointerAlignment: Left" would not add a space in this case.

Reviewers: klimek, owenpan, krasimir, timwoj

Reviewed By: klimek

Subscribers: cfe-commits

Tags: #clang-tools-extra, #clang

Differential Revision: https://reviews.llvm.org/D67718

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@372249 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 11 insertions, 1 deletions

diff --git a/lib/Format/TokenAnnotator.cpp b/lib/Format/TokenAnnotator.cpp
index 9802711834..e584eec368 100644
--- a/lib/Format/TokenAnnotator.cpp
+++ b/lib/Format/TokenAnnotator.cpp
@@ -2580,7 +2580,8 @@ bool TokenAnnotator::spaceRequiredBetween(const AnnotatedLine &Line,
             (Style.PointerAlignment != FormatStyle::PAS_Right &&
              !Line.IsMultiVariableDeclStmt) &&
             Left.Previous &&
-            !Left.Previous->isOneOf(tok::l_paren, tok::coloncolon));
+            !Left.Previous->isOneOf(tok::l_paren, tok::coloncolon,
+                                    tok::l_square));
   if (Right.is(tok::star) && Left.is(tok::l_paren))
     return false;
   const auto SpaceRequiredForArrayInitializerLSquare =
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index dc20faf70c..0f5040488e 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -14074,6 +14074,15 @@ TEST_F(FormatTest, TypenameMacros) {
   verifyFormat("STACK_OF(int*)* a;", Macros);
 }
 
+TEST_F(FormatTest, AmbersandInLamda) {
+  // Test case reported in https://bugs.llvm.org/show_bug.cgi?id=41899
+  FormatStyle AlignStyle = getLLVMStyle();
+  AlignStyle.PointerAlignment = FormatStyle::PAS_Left;
+  verifyFormat("auto lambda = [&a = a]() { a = 2; };", AlignStyle);
+  AlignStyle.PointerAlignment = FormatStyle::PAS_Right;
+  verifyFormat("auto lambda = [&a = a]() { a = 2; };", AlignStyle);
+}
+
 } // end namespace
 } // end namespace format
 } // end namespace clang