Improve Wrange-loop-analyses for rvalue reference

The Wrange-loop-analyses warns if a copy is made. Suppress this warning when
a temporary is bound to a rvalue reference.

While fixing this issue also found a copy-paste error in test6, which is also
fixed.

Differential Revision: https://reviews.llvm.org/D71806

1 files changed, 3 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 959adbf1c35..1e7cc503d8c 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -2764,9 +2764,11 @@ static void DiagnoseForRangeReferenceVariableCopies(Sema &SemaRef,
     SemaRef.Diag(VD->getBeginLoc(), diag::note_use_type_or_non_reference)
         << NonReferenceType << NewReferenceType << VD->getSourceRange()
         << FixItHint::CreateRemoval(VD->getTypeSpecEndLoc());
-  } else {
+  } else if (!VariableType->isRValueReferenceType()) {
     // The range always returns a copy, so a temporary is always created.
     // Suggest removing the reference from the loop variable.
+    // If the type is a rvalue reference do not warn since that changes the
+    // semantic of the code.
     SemaRef.Diag(VD->getLocation(), diag::warn_for_range_variable_always_copy)
         << VD << RangeInitType;
     QualType NonReferenceType = VariableType.getNonReferenceType();