[clang-format] Handle leading comments in using declaration

This fixes clang-format internal assertion for the following code:

  /* override */ using std::string;

Patch by Igor Sugak. Thank you.

llvm-svn: 317901

2 files changed, 13 insertions, 4 deletions

diff --git a/clang/lib/Format/UsingDeclarationsSorter.cpp b/clang/lib/Format/UsingDeclarationsSorter.cpp
index 72151137eed..2c124ec78b1 100644
--- a/clang/lib/Format/UsingDeclarationsSorter.cpp
+++ b/clang/lib/Format/UsingDeclarationsSorter.cpp
@@ -172,15 +172,17 @@ std::pair<tooling::Replacements, unsigned> UsingDeclarationsSorter::analyze(
   tooling::Replacements Fixes;
   SmallVector<UsingDeclaration, 4> UsingDeclarations;
   for (size_t I = 0, E = AnnotatedLines.size(); I != E; ++I) {
+    const auto *FirstTok = AnnotatedLines[I]->First;
     if (AnnotatedLines[I]->InPPDirective ||
-        !AnnotatedLines[I]->startsWith(tok::kw_using) ||
-        AnnotatedLines[I]->First->Finalized) {
+        !AnnotatedLines[I]->startsWith(tok::kw_using) || FirstTok->Finalized) {
       endUsingDeclarationBlock(&UsingDeclarations, SourceMgr, &Fixes);
       continue;
     }
-    if (AnnotatedLines[I]->First->NewlinesBefore > 1)
+    if (FirstTok->NewlinesBefore > 1)
       endUsingDeclarationBlock(&UsingDeclarations, SourceMgr, &Fixes);
-    std::string Label = computeUsingDeclarationLabel(AnnotatedLines[I]->First);
+    const auto *UsingTok =
+        FirstTok->is(tok::comment) ? FirstTok->getNextNonComment() : FirstTok;
+    std::string Label = computeUsingDeclarationLabel(UsingTok);
     if (Label.empty()) {
       endUsingDeclarationBlock(&UsingDeclarations, SourceMgr, &Fixes);
       continue;
diff --git a/clang/unittests/Format/UsingDeclarationsSorterTest.cpp b/clang/unittests/Format/UsingDeclarationsSorterTest.cpp
index e72076a8e31..37427a51f82 100644
--- a/clang/unittests/Format/UsingDeclarationsSorterTest.cpp
+++ b/clang/unittests/Format/UsingDeclarationsSorterTest.cpp
@@ -348,6 +348,13 @@ TEST_F(UsingDeclarationsSorterTest, SortsPartialRangeOfUsingDeclarations) {
                                   {tooling::Range(19, 1)}));
 }
 
+TEST_F(UsingDeclarationsSorterTest, SortsUsingDeclarationsWithLeadingkComments) {
+  EXPECT_EQ("/* comment */ using a;\n"
+            "/* comment */ using b;",
+            sortUsingDeclarations("/* comment */ using b;\n"
+                                  "/* comment */ using a;"));
+}
+
 } // end namespace
 } // end namespace format
 } // end namespace clang