Allow breaking after "::" if absolutely necessary.

Otherwise, really long nested name specifiers can easily lead to a
violation of the column limit.

Not sure about the rules for indentation in those cases, so input is
appreciated (see tests.).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173438 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 34 insertions, 4 deletions

diff --git a/lib/Format/Format.cpp b/lib/Format/Format.cpp
index b16eb15318..1cac334125 100644
--- a/lib/Format/Format.cpp
+++ b/lib/Format/Format.cpp
@@ -688,6 +688,8 @@ private:
       return 50;
     if (Left.is(tok::equal) && Right.is(tok::l_brace))
       return 150;
+    if (Left.is(tok::coloncolon))
+      return 500;
 
     // In for-loops, prefer breaking at ',' and ';'.
     if (RootToken.is(tok::kw_for) &&
@@ -1597,10 +1599,11 @@ private:
     return (isBinaryOperator(Left) && Left.isNot(tok::lessless)) ||
            Left.is(tok::comma) || Right.is(tok::lessless) ||
            Right.is(tok::arrow) || Right.is(tok::period) ||
-           Right.is(tok::colon) || Left.is(tok::semi) ||
-           Left.is(tok::l_brace) || Left.is(tok::question) || Left.Type ==
-           TT_ConditionalExpr || (Left.is(tok::r_paren) && Left.Type !=
-                                  TT_CastRParen && Right.is(tok::identifier)) ||
+           Right.is(tok::colon) || Left.is(tok::coloncolon) ||
+           Left.is(tok::semi) || Left.is(tok::l_brace) ||
+           Left.is(tok::question) || Left.Type == TT_ConditionalExpr ||
+           (Left.is(tok::r_paren) && Left.Type != TT_CastRParen &&
+            Right.is(tok::identifier)) ||
            (Left.is(tok::l_paren) && !Right.is(tok::r_paren));
   }
 
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index d8a6ddcb68..2250c03b58 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -1204,6 +1204,33 @@ TEST_F(FormatTest, WrapsTemplateDeclarations) {
       "void f();");
 }
 
+TEST_F(FormatTest, WrapsAtNestedNameSpecifiers) {
+  verifyFormat(
+      "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa::\n"
+      "    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa();");
+  verifyFormat(
+      "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa::\n"
+      "    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(\n"
+      "        aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa());");
+
+  // FIXME: Should we have an extra indent after the second break?
+  verifyFormat(
+      "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa::\n"
+      "    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa::\n"
+      "    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa();");
+
+  // FIXME: Look into whether we should indent 4 from the start or 4 from
+  // "bbbbb..." here instead of what we are doing now.
+  verifyFormat(
+      "aaaaaaaaaaaaaaa(bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb::\n"
+      "                cccccccccccccccccccccccccccccccccccccccccccccccccc());");
+
+  // Breaking at nested name specifiers is generally not desirable.
+  verifyFormat(
+      "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa::aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(\n"
+      "    aaaaaaaaaaaaaaaaaaaaaaa);");
+}
+
 TEST_F(FormatTest, UnderstandsTemplateParameters) {
   verifyFormat("A<int> a;");
   verifyFormat("A<A<A<int> > > a;");