Add unit tests for bug 981: valid and invalid usage of ternary operator

failtest/CMakeLists.txt

@@ -41,6 +41,9 @@ ei_add_failtest("ref_5")
 ei_add_failtest("swap_1")
 ei_add_failtest("swap_2")
 
+ei_add_failtest("ternary_1")
+ei_add_failtest("ternary_2")
+
 ei_add_failtest("sparse_ref_1")
 ei_add_failtest("sparse_ref_2")
 ei_add_failtest("sparse_ref_3")

failtest/ternary_1.cpp

@@ -0,0 +1,13 @@
+#include "../Eigen/Core"
+
+using namespace Eigen;
+
+int main(int argc,char **)
+{
+  VectorXf a(10), b(10);
+#ifdef EIGEN_SHOULD_FAIL_TO_BUILD
+  b = argc>1 ? 2*a : -a;
+#else
+  b = argc>1 ? 2*a : VectorXf(-a);
+#endif
+}

failtest/ternary_2.cpp

@@ -0,0 +1,13 @@
+#include "../Eigen/Core"
+
+using namespace Eigen;
+
+int main(int argc,char **)
+{
+  VectorXf a(10), b(10);
+#ifdef EIGEN_SHOULD_FAIL_TO_BUILD
+  b = argc>1 ? 2*a : a+a;
+#else
+  b = argc>1 ? VectorXf(2*a) : VectorXf(a+a);
+#endif
+}

test/basicstuff.cpp

@@ -126,6 +126,20 @@ template<typename MatrixType> void basicStuff(const MatrixType& m)
   for(typename MatrixType::Index i=0;i<rows;++i)
     sm2.col(i).noalias() -= sm1.row(i);
   VERIFY_IS_APPROX(sm2,-sm1.transpose());
+
+  // check ternary usage
+  {
+    bool b = internal::random<int>(0,10)>5;
+    m3 = b ? m1 : m2;
+    if(b) VERIFY_IS_APPROX(m3,m1);
+    else  VERIFY_IS_APPROX(m3,m2);
+    m3 = b ? -m1 : m2;
+    if(b) VERIFY_IS_APPROX(m3,-m1);
+    else  VERIFY_IS_APPROX(m3,m2);
+    m3 = b ? m1 : -m2;
+    if(b) VERIFY_IS_APPROX(m3,m1);
+    else  VERIFY_IS_APPROX(m3,-m2);
+  }
 }
 
 template<typename MatrixType> void basicStuffComplex(const MatrixType& m)