clang-format: remove trailing lines in lamdas and arrow functions.

Summary:
clang-format already removes empty lines at the beginning & end of
blocks:

    int x() {

      foo();  // lines before and after will be removed.

    }

However because lamdas and arrow functions are parsed as expressions,
the existing logic to remove empty lines in UnwrappedLineFormatter
doesn't handle them.

This change special cases arrow functions in ContinuationIndenter to
remove empty lines:

    x = []() {

      foo();  // lines before and after will now be removed.

    };

Reviewers: djasper

Subscribers: klimek, cfe-commits

Differential Revision: https://reviews.llvm.org/D40178

llvm-svn: 318537

2 files changed, 30 insertions, 3 deletions

diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 7fbf01dc129..acff8d32320 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -70,18 +70,23 @@ protected:
     return getStyleWithColumns(getGoogleStyle(), ColumnLimit);
   }
 
-  void verifyFormat(llvm::StringRef Code,
+  void verifyFormat(llvm::StringRef Expected, llvm::StringRef Code,
                     const FormatStyle &Style = getLLVMStyle()) {
-    EXPECT_EQ(Code.str(), format(test::messUp(Code), Style));
+    EXPECT_EQ(Expected.str(), format(Code, Style));
     if (Style.Language == FormatStyle::LK_Cpp) {
       // Objective-C++ is a superset of C++, so everything checked for C++
       // needs to be checked for Objective-C++ as well.
       FormatStyle ObjCStyle = Style;
       ObjCStyle.Language = FormatStyle::LK_ObjC;
-      EXPECT_EQ(Code.str(), format(test::messUp(Code), ObjCStyle));
+      EXPECT_EQ(Expected.str(), format(test::messUp(Code), ObjCStyle));
     }
   }
 
+  void verifyFormat(llvm::StringRef Code,
+                    const FormatStyle &Style = getLLVMStyle()) {
+    verifyFormat(Code, test::messUp(Code), Style);
+  }
+
   void verifyIncompleteFormat(llvm::StringRef Code,
                               const FormatStyle &Style = getLLVMStyle()) {
     EXPECT_EQ(Code.str(),
@@ -11089,6 +11094,17 @@ TEST_F(FormatTest, FormatsLambdas) {
       "    });");
 }
 
+TEST_F(FormatTest, EmptyLinesInLambdas) {
+  verifyFormat("auto lambda = []() {\n"
+               "  x(); //\n"
+               "};",
+               "auto lambda = []() {\n"
+               "\n"
+               "  x(); //\n"
+               "\n"
+               "};");
+}
+
 TEST_F(FormatTest, FormatsBlocks) {
   FormatStyle ShortBlocks = getLLVMStyle();
   ShortBlocks.AllowShortBlocksOnASingleLine = true;
diff --git a/clang/unittests/Format/FormatTestJS.cpp b/clang/unittests/Format/FormatTestJS.cpp
index 3df01663e9d..3e5abdc098a 100644
--- a/clang/unittests/Format/FormatTestJS.cpp
+++ b/clang/unittests/Format/FormatTestJS.cpp
@@ -1606,6 +1606,17 @@ TEST_F(FormatTestJS, TypeInterfaceLineWrapping) {
       Style);
 }
 
+TEST_F(FormatTestJS, RemoveEmptyLinesInArrowFunctions) {
+  verifyFormat("x = () => {\n"
+               "  foo();\n"
+               "};\n",
+               "x = () => {\n"
+               "\n"
+               "  foo();\n"
+               "\n"
+               "};\n");
+}
+
 TEST_F(FormatTestJS, Modules) {
   verifyFormat("import SomeThing from 'some/module.js';");
   verifyFormat("import {X, Y} from 'some/module.js';");