As proposed on the list:

- rename EvalBeforeAssignBit to MayAliasBit
- make .lazy() remove the MayAliasBit only, and mark it as deprecated
- add a NoAlias pseudo expression, and MatrixBase::noalias() function
Todo:
- we have to decide whether += and -= assume no aliasing by default ?
- once we agree on the API: update the Sparse module and the unit tests respectively.

test/submatrices.cpp

@@ -86,7 +86,8 @@ template<typename MatrixType> void submatrices(const MatrixType& m)
 
   //check row() and col()
   VERIFY_IS_APPROX(m1.col(c1).transpose(), m1.transpose().row(c1));
-  VERIFY_IS_APPROX(m1.col(c1).dot(square.row(r1)), (square.lazy() * m1.conjugate()).eval()(r1,c1));
+  // FIXME perhaps we should re-enable that without the .eval()
+  VERIFY_IS_APPROX(m1.col(c1).dot(square.row(r1)), (square * m1.conjugate()).eval()(r1,c1));
   //check operator(), both constant and non-constant, on row() and col()
   m1.row(r1) += s1 * m1.row(r2);
   m1.col(c1) += s1 * m1.col(c2);