clang-format: Fix corner case for lambda assignments.

Before:
  std::function<std::string(const std::string &)> my_lambda = [](
      const string &s) { return s; };

After:
  std::function<std::string(const std::string &)> my_lambda =
      [](const string &s) { return s; };

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@256739 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Format/TokenAnnotator.cpp

@@ -1722,7 +1722,7 @@ unsigned TokenAnnotator::splitPenalty(const AnnotatedLine &Line,
       return 25;
     // Slightly prefer formatting local lambda definitions like functions.
     if (Right.is(TT_LambdaLSquare) && Left.is(tok::equal))
-      return 50;
+      return 35;
     if (!Right.isOneOf(TT_ObjCMethodExpr, TT_LambdaLSquare,
                        TT_ArrayInitializerLSquare))
       return 500;

unittests/Format/FormatTest.cpp

@@ -10512,6 +10512,8 @@ TEST_F(FormatTest, FormatsLambdas) {
   verifyFormat("auto my_lambda = [](const string &some_parameter) {\n"
                "  return some_parameter.size();\n"
                "};");
+  verifyFormat("std::function<std::string(const std::string &)> my_lambda =\n"
+               "    [](const string &s) { return s; };");
   verifyFormat("int i = aaaaaa ? 1 //\n"
                "               : [] {\n"
                "                   return 2; //\n"