Math: test that implicit conversion of underlying type can't compile.

src/Math/Test/Matrix3Test.cpp

@@ -135,6 +135,9 @@ void Matrix3Test::constructConversion() {
     CORRADE_COMPARE(b, Matrix3i({3,  5, 8},
                                 {4,  4, 7},
                                 {7, -1, 8}));
+
+    /* Implicit conversion is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<Matrix3, Matrix3i>::value));
 }
 
 void Matrix3Test::constructCopy() {

src/Math/Test/Matrix4Test.cpp

@@ -154,6 +154,9 @@ void Matrix4Test::constructConversion() {
                                 {4,  4, 7,  2},
                                 {1,  2, 3, -1},
                                 {7, -1, 8, -1}));
+
+    /* Implicit conversion is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<Matrix4, Matrix4i>::value));
 }
 
 void Matrix4Test::constructCopy() {

src/Math/Test/MatrixTest.cpp

@@ -132,6 +132,9 @@ void MatrixTest::constructConversion() {
                                 Vector4i(4,  4, 7,  2),
                                 Vector4i(1,  2, 3, -1),
                                 Vector4i(7, -1, 8, -1)));
+
+    /* Implicit conversion is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<Matrix4, Matrix4i>::value));
 }
 
 void MatrixTest::constructCopy() {

src/Math/Test/RectangularMatrixTest.cpp

@@ -134,6 +134,9 @@ void RectangularMatrixTest::constructConversion() {
 
     CORRADE_COMPARE(b, Matrix2i(Vector2i(  1, 2),
                                 Vector2i(-15, 7)));
+
+    /* Implicit conversion is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<Matrix2, Matrix2i>::value));
 }
 
 void RectangularMatrixTest::constructFromData() {

src/Math/Test/Vector2Test.cpp

@@ -120,6 +120,9 @@ void Vector2Test::constructConversion() {
     Vector2i b(a); /* Not constexpr under GCC < 4.7 */
     #endif
     CORRADE_COMPARE(b, Vector2i(1, 2));
+
+    /* Implicit conversion is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<Vector2, Vector2i>::value));
 }
 
 void Vector2Test::constructCopy() {

src/Math/Test/Vector3Test.cpp

@@ -133,6 +133,9 @@ void Vector3Test::constructConversion() {
     Vector3i b(a); /* Not constexpr under GCC < 4.7 */
     #endif
     CORRADE_COMPARE(b, Vector3i(1, 2, -3));
+
+    /* Implicit conversion is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<Vector3, Vector3i>::value));
 }
 
 void Vector3Test::constructCopy() {

src/Math/Test/Vector4Test.cpp

@@ -130,6 +130,9 @@ void Vector4Test::constructConversion() {
     Vector4i b(a); /* Not constexpr under GCC < 4.7 */
     #endif
     CORRADE_COMPARE(b, Vector4i(1, -2, 3, 4));
+
+    /* Implicit conversion is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<Vector4, Vector4i>::value));
 }
 
 void Vector4Test::constructCopy() {

src/Math/Test/VectorTest.cpp

@@ -187,6 +187,9 @@ void VectorTest::constructConversion() {
     #endif
 
     CORRADE_COMPARE(b, Vector4i(1, 2, -15, 7));
+
+    /* Implicit conversion is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<Vector4, Vector4i>::value));
 }
 
 void VectorTest::constructCopy() {