Allow breaking after the trailing const after a function declaration.

Before:
void aaaaaaaaaaaa(int aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa) const GUARDED_BY(
    aaaaaaaaaaaaa);

After:
void aaaaaaaaaaaa(int aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa) const
    GUARDED_BY(aaaaaaaaaaaaa);

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@172718 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Format/Format.cpp

@@ -1390,6 +1390,13 @@ private:
       // change the "binding" behavior of a comment.
       return false;
 
+    // Allow breaking after a trailing 'const', e.g. after a method declaration,
+    // unless it is follow by ';', '{' or '='.
+    if (Left.is(tok::kw_const) && Left.Parent != NULL &&
+        Left.Parent->is(tok::r_paren))
+      return Right.isNot(tok::l_brace) && Right.isNot(tok::semi) &&
+             Right.isNot(tok::equal);
+
     // We only break before r_brace if there was a corresponding break before
     // the l_brace, which is tracked by BreakBeforeClosingBrace.
     if (Right.is(tok::r_brace))

unittests/Format/FormatTest.cpp

@@ -899,6 +899,10 @@ TEST_F(FormatTest, FormatsOneParameterPerLineIfNecessary) {
 TEST_F(FormatTest, DoesNotBreakTrailingAnnotation) {
   verifyFormat("void aaaaaaaaaaaa(int aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa)\n"
                "    GUARDED_BY(aaaaaaaaaaaaa);");
+  verifyFormat("void aaaaaaaaaaaa(int aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa) const\n"
+               "    GUARDED_BY(aaaaaaaaaaaaa);");
+  verifyFormat("void aaaaaaaaaaaa(int aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa) const\n"
+               "    GUARDED_BY(aaaaaaaaaaaaa) {}");
 }
 
 TEST_F(FormatTest, BreaksAccordingToOperatorPrecedence) {