bug #1646: fix false aliasing detection for A.row(0) = A.col(0);
This changeset completely disable the detection for vectors for which are current mechanism cannot detect any positive aliasing anyway.

Eigen/src/Core/Transpose.h

diff --git a/Eigen/src/Core/Transpose.h b/Eigen/src/Core/Transpose.h
index 6255a2f..91a9ab1 100644
--- a/Eigen/src/Core/Transpose.h
+++ b/Eigen/src/Core/Transpose.h
@@ -392,7 +392,7 @@
 template<typename Dst, typename Src>
 void check_for_aliasing(const Dst &dst, const Src &src)
 {
-  if(src.size()>1)
+  if((!Dst::IsVectorAtCompileTime) && dst.rows()>1 && dst.cols()>1)
     internal::checkTransposeAliasing_impl<Dst, Src>::run(dst, src);
 }