Have LoopConvert use 'auto &&' where necessary

For iterators where the dereference operator returns by value, LoopConvert
should use 'auto &&' in the range-based for loop expression.

If the dereference operator returns an rvalue reference, this is deemed too
strange and the for loop is not converted.

Moved test case from iterator_failing.cpp to iterator.cpp and added extra
tests.

Fixes PR15437.

Reviewer: gribozavr
llvm-svn: 176631

1 files changed, 3 insertions, 1 deletions

diff --git a/clang-tools-extra/cpp11-migrate/LoopConvert/LoopActions.h b/clang-tools-extra/cpp11-migrate/LoopConvert/LoopActions.h
index 504e6ab64d2..bd91a98f7bd 100644
--- a/clang-tools-extra/cpp11-migrate/LoopConvert/LoopActions.h
+++ b/clang-tools-extra/cpp11-migrate/LoopConvert/LoopActions.h
@@ -74,7 +74,8 @@ class LoopFixer : public clang::ast_matchers::MatchFinder::MatchCallback {
                     const UsageResult &Usages,
                     const clang::DeclStmt *AliasDecl,
                     const clang::ForStmt *TheLoop,
-                    bool ContainerNeedsDereference);
+                    bool ContainerNeedsDereference,
+                    bool DerefByValue);
 
   /// \brief Given a loop header that would be convertible, discover all usages
   /// of the index variable and convert the loop if possible.
@@ -84,6 +85,7 @@ class LoopFixer : public clang::ast_matchers::MatchFinder::MatchCallback {
                            const clang::Expr *ContainerExpr,
                            const clang::Expr *BoundExpr,
                            bool ContainerNeedsDereference,
+                           bool DerefByValue,
                            const clang::ForStmt *TheLoop,
                            Confidence ConfidenceLevel);