From e9bea614ecb6d910948e36b11483bbb0c0f83f76 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Mon, 29 Feb 2016 10:31:27 +0100
Subject: [PATCH] Fix shortcoming in fixed-value deduction of startRow/startCol

---
 Eigen/src/Core/Block.h          | 8 ++++----
 Eigen/src/Core/CoreEvaluators.h | 4 ++--
 test/block.cpp                  | 5 +++++
 3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/Eigen/src/Core/Block.h b/Eigen/src/Core/Block.h
index 2f46c878d..11de45c2e 100644
--- a/Eigen/src/Core/Block.h
+++ b/Eigen/src/Core/Block.h
@@ -318,8 +318,8 @@ template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel, bool H
   protected:
 
     XprTypeNested m_xpr;
-    const internal::variable_if_dynamic<StorageIndex, XprType::RowsAtCompileTime == 1 ? 0 : Dynamic> m_startRow;
-    const internal::variable_if_dynamic<StorageIndex, XprType::ColsAtCompileTime == 1 ? 0 : Dynamic> m_startCol;
+    const internal::variable_if_dynamic<StorageIndex, (XprType::RowsAtCompileTime == 1 && BlockRows==1) ? 0 : Dynamic> m_startRow;
+    const internal::variable_if_dynamic<StorageIndex, (XprType::ColsAtCompileTime == 1 && BlockCols==1) ? 0 : Dynamic> m_startCol;
     const internal::variable_if_dynamic<StorageIndex, RowsAtCompileTime> m_blockRows;
     const internal::variable_if_dynamic<StorageIndex, ColsAtCompileTime> m_blockCols;
 };
@@ -440,8 +440,8 @@ class BlockImpl_dense<XprType,BlockRows,BlockCols, InnerPanel,true>
     }
 
     XprTypeNested m_xpr;
-    const internal::variable_if_dynamic<StorageIndex, XprType::RowsAtCompileTime == 1 ? 0 : Dynamic> m_startRow;
-    const internal::variable_if_dynamic<StorageIndex, XprType::ColsAtCompileTime == 1 ? 0 : Dynamic> m_startCol;
+    const internal::variable_if_dynamic<StorageIndex, (XprType::RowsAtCompileTime == 1 && BlockRows==1) ? 0 : Dynamic> m_startRow;
+    const internal::variable_if_dynamic<StorageIndex, (XprType::ColsAtCompileTime == 1 && BlockCols==1) ? 0 : Dynamic> m_startCol;
     Index m_outerStride;
 };
 
diff --git a/Eigen/src/Core/CoreEvaluators.h b/Eigen/src/Core/CoreEvaluators.h
index a729e0454..388805f0d 100644
--- a/Eigen/src/Core/CoreEvaluators.h
+++ b/Eigen/src/Core/CoreEvaluators.h
@@ -865,8 +865,8 @@ struct unary_evaluator<Block<ArgType, BlockRows, BlockCols, InnerPanel>, IndexBa
  
 protected:
   evaluator<ArgType> m_argImpl;
-  const variable_if_dynamic<Index, ArgType::RowsAtCompileTime == 1 ? 0 : Dynamic> m_startRow;
-  const variable_if_dynamic<Index, ArgType::ColsAtCompileTime == 1 ? 0 : Dynamic> m_startCol;
+  const variable_if_dynamic<Index, (ArgType::RowsAtCompileTime == 1 && BlockRows==1) ? 0 : Dynamic> m_startRow;
+  const variable_if_dynamic<Index, (ArgType::ColsAtCompileTime == 1 && BlockCols==1) ? 0 : Dynamic> m_startCol;
 };
 
 // TODO: This evaluator does not actually use the child evaluator; 
diff --git a/test/block.cpp b/test/block.cpp
index 3b77b704a..1eeb2da27 100644
--- a/test/block.cpp
+++ b/test/block.cpp
@@ -181,6 +181,11 @@ template<typename MatrixType> void block(const MatrixType& m)
   dm = m1.row(r1).segment(c1,c2-c1+1).transpose();
   dv = m1.transpose().block(c1,r1,c2-c1+1,r2-r1+1).col(0);
   VERIFY_IS_EQUAL(dv, dm);
+
+  VERIFY_IS_EQUAL( (m1.template block<Dynamic,1>(1,0,0,1)), m1.block(1,0,0,1));
+  VERIFY_IS_EQUAL( (m1.template block<1,Dynamic>(0,1,1,0)), m1.block(0,1,1,0));
+  VERIFY_IS_EQUAL( ((m1*1).template block<Dynamic,1>(1,0,0,1)), m1.block(1,0,0,1));
+  VERIFY_IS_EQUAL( ((m1*1).template block<1,Dynamic>(0,1,1,0)), m1.block(0,1,1,0));
 }