ClangFormat: Fix keeping line breaks for lambdas

Tweak the bahaviour of keeping line breaks for child tokens.

Change-Id: I38f073b2ad8f554c44abbc80cfae7e89273fc60f
Reviewed-by: Marco Bubke <marco.bubke@qt.io>

3 files changed, 15 insertions, 5 deletions

diff --git a/lib/Format/UnwrappedLineFormatter.cpp b/lib/Format/UnwrappedLineFormatter.cpp
index 7e1d805a5f..d4dbdc5544 100644
--- a/lib/Format/UnwrappedLineFormatter.cpp
+++ b/lib/Format/UnwrappedLineFormatter.cpp
@@ -715,7 +715,8 @@ protected:
       // assert so that we can simply call this function for all tokens.
       return true;
 
-    if (NewLine) {
+    if (NewLine || (Previous.Children[0]->First->MustBreakBefore &&
+                    Style.KeepLineBreaksForNonEmptyLines)) {
       int AdditionalIndent = State.Stack.back().Indent -
                              Previous.Children[0]->Level * Style.IndentWidth;
 
@@ -786,8 +787,7 @@ public:
     while (State.NextToken) {
       bool Newline =
           Indenter->mustBreak(State) ||
-          (State.NextToken->NewlinesBefore > 0 &&
-           (Style.KeepLineBreaksForNonEmptyLines || Indenter->canBreak(State)));
+          (State.NextToken->NewlinesBefore > 0 && Indenter->canBreak(State));
       unsigned Penalty = 0;
       formatChildren(State, Newline, /*DryRun=*/false, Penalty);
       Indenter->addTokenToState(State, Newline, /*DryRun=*/false);
diff --git a/lib/Format/UnwrappedLineParser.cpp b/lib/Format/UnwrappedLineParser.cpp
index e5afa1264a..b363506bb2 100644
--- a/lib/Format/UnwrappedLineParser.cpp
+++ b/lib/Format/UnwrappedLineParser.cpp
@@ -2517,6 +2517,8 @@ void UnwrappedLineParser::nextToken(int LevelDifference) {
   else
     readTokenWithJavaScriptASI();
   FormatTok->Previous = Previous;
+  if (FormatTok->NewlinesBefore && Style.KeepLineBreaksForNonEmptyLines)
+    FormatTok->MustBreakBefore = true;
 }
 
 void UnwrappedLineParser::distributeComments(
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index 3c94e4c9af..f9b575b289 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -353,9 +353,17 @@ TEST_F(FormatTest, RemovesEmptyLines) {
   Style.KeepLineBreaksForNonEmptyLines = true;
   Style.ColumnLimit = 0;
   EXPECT_EQ("int foo(int a,\n"
-            "        int b) {}",
+            "        int b)\n"
+            "{\n"
+            "}",
             format("int foo(int a,\n"
-                   "        int b) {}",
+                   "int b) {}",
+                   Style));
+
+  EXPECT_EQ("[]() {\n"
+            "  foo(); }",
+            format("[]() {\n"
+                   "foo(); }",
                    Style));
 }