Fix bugs around handling C++11 attributes.

Previously, we would format:
  int a() { ... }
  [[unused]] int b() { ... }
as...
  int a() {} [[unused] int b() {}
Now we correctly format each on its own line.

Similarly, we would detect:
  [[unused]] int b() { return 42; }
As a lambda and leave it on a single line, even if that was disallowed
by the format style.

llvm-svn: 329816

2 files changed, 27 insertions, 2 deletions

diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index be7e2bbabac..b61ffb21d84 100644
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -449,12 +449,19 @@ void UnwrappedLineParser::calculateBraceTypes(bool ExpectClassBody) {
               (Style.isCpp() && NextTok->is(tok::l_paren)) ||
               NextTok->isOneOf(tok::comma, tok::period, tok::colon,
                                tok::r_paren, tok::r_square, tok::l_brace,
-                               tok::l_square, tok::ellipsis) ||
+                               tok::ellipsis) ||
               (NextTok->is(tok::identifier) &&
                !PrevTok->isOneOf(tok::semi, tok::r_brace, tok::l_brace)) ||
               (NextTok->is(tok::semi) &&
                (!ExpectClassBody || LBraceStack.size() != 1)) ||
               (NextTok->isBinaryOperator() && !NextIsObjCMethod);
+          if (NextTok->is(tok::l_square)) {
+            // We can have an array subscript after a braced init
+            // list, but C++11 attributes are expected after blocks.
+            NextTok = Tokens->getNextToken();
+            ++ReadTokens;
+            ProbablyBracedList = NextTok->isNot(tok::l_square);
+          }
         }
         if (ProbablyBracedList) {
           Tok->BlockKind = BK_BracedInit;
@@ -1406,13 +1413,16 @@ bool UnwrappedLineParser::tryToParseLambdaIntroducer() {
   const FormatToken *Previous = FormatTok->Previous;
   if (Previous &&
       (Previous->isOneOf(tok::identifier, tok::kw_operator, tok::kw_new,
-                         tok::kw_delete) ||
+                         tok::kw_delete, tok::l_square) ||
        FormatTok->isCppStructuredBinding(Style) || Previous->closesScope() ||
        Previous->isSimpleTypeSpecifier())) {
     nextToken();
     return false;
   }
   nextToken();
+  if (FormatTok->is(tok::l_square)) {
+    return false;
+  }
   parseSquare(/*LambdaIntroducer=*/true);
   return true;
 }
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 43225304670..4abf978b721 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -6078,6 +6078,21 @@ TEST_F(FormatTest, UnderstandsSquareAttributes) {
   verifyFormat("void f() [[deprecated(\"so sorry\")]];");
   verifyFormat("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
                "    [[unused]] aaaaaaaaaaaaaaaaaaaaaaa(int i);");
+
+  // Make sure we do not mistake attributes for array subscripts.
+  verifyFormat("int a() {}\n"
+               "[[unused]] int b() {}\n");
+
+  // On the other hand, we still need to correctly find array subscripts.
+  verifyFormat("int a = std::vector<int>{1, 2, 3}[0];");
+
+  // Make sure we do not parse attributes as lambda introducers.
+  FormatStyle MultiLineFunctions = getLLVMStyle();
+  MultiLineFunctions.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_None;
+  verifyFormat("[[unused]] int b() {\n"
+               "  return 42;\n"
+               "}\n",
+               MultiLineFunctions);
 }
 
 TEST_F(FormatTest, UnderstandsEllipsis) {