MSVC 2015 compatibility: Math copy/conversion constexpr issues.

I don't know why, but marking the output of copy constructor of any
subclass or output of conversion operator of any class as constexpr
causes MSVC to complain about non-constant expression.

Probably just another bug.

src/Magnum/Math/Test/ColorTest.cpp

@@ -203,11 +203,17 @@ void ColorTest::constructNormalization() {
 
 void ColorTest::constructCopy() {
     constexpr Math::Vector<3, Float> a(1.0f, 0.5f, 0.75f);
-    constexpr Color3 b(a);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be copy constexpr? */
+    constexpr
+    #endif
+    Color3 b(a);
     CORRADE_COMPARE(b, Color3(1.0f, 0.5f, 0.75f));
 
     constexpr Math::Vector<4, Float> c(1.0f, 0.5f, 0.75f, 0.25f);
-    constexpr Color4 d(c);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be copy constexpr? */
+    constexpr
+    #endif
+    Color4 d(c);
     CORRADE_COMPARE(d, Color4(1.0f, 0.5f, 0.75f, 0.25f));
 }
 

src/Magnum/Math/Test/ComplexTest.cpp

@@ -196,7 +196,10 @@ void ComplexTest::convert() {
     Complex c(a);
     CORRADE_COMPARE(c, b);
 
-    constexpr Cmpl d(b);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be conversion constexpr? */
+    constexpr
+    #endif
+    Cmpl d(b);
     CORRADE_COMPARE(d.re, a.re);
     CORRADE_COMPARE(d.im, a.im);
 

src/Magnum/Math/Test/DualComplexTest.cpp

@@ -171,7 +171,10 @@ void DualComplexTest::constructFromVector() {
 
 void DualComplexTest::constructCopy() {
     constexpr Math::Dual<Complex> a({-1.0f, 2.5f}, {3.0f, -7.5f});
-    constexpr DualComplex b(a);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be copy constexpr? */
+    constexpr
+    #endif
+    DualComplex b(a);
     CORRADE_COMPARE(b, DualComplex({-1.0f, 2.5f}, {3.0f, -7.5f}));
 }
 
@@ -190,7 +193,10 @@ void DualComplexTest::convert() {
     DualComplex c{a};
     CORRADE_COMPARE(c, b);
 
-    constexpr DualCmpl d(b);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be conversion constexpr? */
+    constexpr
+    #endif
+    DualCmpl d(b);
     CORRADE_COMPARE(d.re, a.re);
     CORRADE_COMPARE(d.im, a.im);
     CORRADE_COMPARE(d.x, a.x);

src/Magnum/Math/Test/DualQuaternionTest.cpp

@@ -172,7 +172,10 @@ void DualQuaternionTest::constructFromVector() {
 
 void DualQuaternionTest::constructCopy() {
     constexpr Math::Dual<Quaternion> a({{1.0f, 2.0f, -3.0f}, -3.5f}, {{4.5f, -7.0f, 2.0f}, 1.0f});
-    constexpr DualQuaternion b(a);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be copy constexpr? */
+    constexpr
+    #endif
+    DualQuaternion b(a);
     CORRADE_COMPARE(b, DualQuaternion({{1.0f, 2.0f, -3.0f}, -3.5f}, {{4.5f, -7.0f, 2.0f}, 1.0f}));
 }
 
@@ -191,7 +194,10 @@ void DualQuaternionTest::convert() {
     DualQuaternion c{a};
     CORRADE_COMPARE(c, b);
 
-    constexpr DualQuat d(b);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be conversion constexpr? */
+    constexpr
+    #endif
+    DualQuat d(b);
     CORRADE_COMPARE(d.re.x, a.re.x);
     CORRADE_COMPARE(d.re.y, a.re.y);
     CORRADE_COMPARE(d.re.z, a.re.z);

src/Magnum/Math/Test/Matrix3Test.cpp

@@ -190,7 +190,10 @@ void Matrix3Test::constructCopy() {
     constexpr RectangularMatrix<3, 3, Float> a(Vector<3, Float>(3.0f,  5.0f, 8.0f),
                                                Vector<3, Float>(4.5f,  4.0f, 7.0f),
                                                Vector<3, Float>(7.9f, -1.0f, 8.0f));
-    constexpr Matrix3 b(a);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be copy constexpr? */
+    constexpr
+    #endif
+    Matrix3 b(a);
     CORRADE_COMPARE(b, Matrix3({3.0f,  5.0f, 8.0f},
                                {4.5f,  4.0f, 7.0f},
                                {7.9f, -1.0f, 8.0f}));
@@ -207,7 +210,10 @@ void Matrix3Test::convert() {
     constexpr Matrix3 c(b);
     CORRADE_COMPARE(c, b);
 
-    constexpr Mat3 d(b);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be conversion constexpr? */
+    constexpr
+    #endif
+    Mat3 d(b);
     for(std::size_t i = 0; i != 9; ++i)
         CORRADE_COMPARE(d.a[0], a.a[0]);
 
@@ -301,7 +307,10 @@ void Matrix3Test::fromParts() {
     constexpr Matrix2x2 rotationScaling(Vector2(3.0f, 5.0f),
                                         Vector2(4.0f, 4.0f));
     constexpr Vector2 translation(7.0f, -1.0f);
-    constexpr Matrix3 a = Matrix3::from(rotationScaling, translation);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+    constexpr
+    #endif
+    Matrix3 a = Matrix3::from(rotationScaling, translation);
 
     CORRADE_COMPARE(a, Matrix3({3.0f,  5.0f, 0.0f},
                                {4.0f,  4.0f, 0.0f},
@@ -312,7 +321,10 @@ void Matrix3Test::rotationScalingPart() {
     constexpr Matrix3 a({3.0f,  5.0f, 8.0f},
                         {4.0f,  4.0f, 7.0f},
                         {7.0f, -1.0f, 8.0f});
-    constexpr Matrix2x2 b = a.rotationScaling();
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+    constexpr
+    #endif
+    Matrix2x2 b = a.rotationScaling();
 
     CORRADE_COMPARE(b, Matrix2x2(Vector2(3.0f, 5.0f),
                                  Vector2(4.0f, 4.0f)));
@@ -380,9 +392,18 @@ void Matrix3Test::vectorParts() {
     constexpr Matrix3 a({15.0f,  0.0f, 0.0f},
                         { 0.0f, -3.0f, 0.0f},
                         {-5.0f, 12.0f, 1.0f});
-    constexpr Vector2 right = a.right();
-    constexpr Vector2 up = a.up();
-    constexpr Vector2 translation = a.translation();
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+    constexpr
+    #endif
+    Vector2 right = a.right();
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+    constexpr
+    #endif
+    Vector2 up = a.up();
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+    constexpr
+    #endif
+    Vector2 translation = a.translation();
 
     CORRADE_COMPARE(right, Vector2::xAxis(15.0f));
     CORRADE_COMPARE(up, Vector2::yAxis(-3.0f));

src/Magnum/Math/Test/Matrix4Test.cpp

@@ -219,7 +219,10 @@ void Matrix4Test::constructCopy() {
                                  Vector<4, Float>(4.5f,  4.0f, 7.0f,  2.0f),
                                  Vector<4, Float>(1.0f,  2.0f, 3.0f, -1.0f),
                                  Vector<4, Float>(7.9f, -1.0f, 8.0f, -1.5f));
-    constexpr Matrix4 b(a);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be copy constexpr? */
+    constexpr
+    #endif
+    Matrix4 b(a);
     CORRADE_COMPARE(b, Matrix4({3.0f,  5.0f, 8.0f, -3.0f},
                                {4.5f,  4.0f, 7.0f,  2.0f},
                                {1.0f,  2.0f, 3.0f, -1.0f},
@@ -239,7 +242,10 @@ void Matrix4Test::convert() {
     constexpr Matrix4 c(b);
     CORRADE_COMPARE(c, b);
 
-    constexpr Mat4 d(b);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be conversion constexpr? */
+    constexpr
+    #endif
+    Mat4 d(b);
     for(std::size_t i = 0; i != 16; ++i)
         CORRADE_COMPARE(d.a[i], a.a[i]);
 
@@ -400,7 +406,10 @@ void Matrix4Test::fromParts() {
                                         Vector3(4.0f,  4.0f, 7.0f),
                                         Vector3(7.0f, -1.0f, 8.0f));
     constexpr Vector3 translation(9.0f, 4.0f, 5.0f);
-    constexpr Matrix4 a = Matrix4::from(rotationScaling, translation);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+    constexpr
+    #endif
+    Matrix4 a = Matrix4::from(rotationScaling, translation);
 
     CORRADE_COMPARE(a, Matrix4({3.0f,  5.0f, 8.0f, 0.0f},
                                {4.0f,  4.0f, 7.0f, 0.0f},
@@ -413,7 +422,10 @@ void Matrix4Test::rotationScalingPart() {
                         {4.0f,  4.0f, 7.0f, 3.0f},
                         {7.0f, -1.0f, 8.0f, 0.0f},
                         {9.0f,  4.0f, 5.0f, 9.0f});
-    constexpr Matrix3x3 b = a.rotationScaling();
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+    constexpr
+    #endif
+    Matrix3x3 b = a.rotationScaling();
 
     CORRADE_COMPARE(b, Matrix3x3(Vector3(3.0f, 5.0f, 8.0f),
                                  Vector3(4.0f, 4.0f, 7.0f),
@@ -486,10 +498,22 @@ void Matrix4Test::vectorParts() {
                         { 0.0f, 12.0f,  0.0f, 0.0f},
                         { 0.0f,  0.0f, 35.0f, 0.0f},
                         {-5.0f, 12.0f,  0.5f, 1.0f});
-    constexpr Vector3 right = a.right();
-    constexpr Vector3 up = a.up();
-    constexpr Vector3 backward = a.backward();
-    constexpr Vector3 translation = a.translation();
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+    constexpr
+    #endif
+    Vector3 right = a.right();
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+    constexpr
+    #endif
+    Vector3 up = a.up();
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+    constexpr
+    #endif
+    Vector3 backward = a.backward();
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+    constexpr
+    #endif
+    Vector3 translation = a.translation();
 
     CORRADE_COMPARE(right, Vector3::xAxis(-1.0f));
     CORRADE_COMPARE(up, Vector3::yAxis(12.0f));

src/Magnum/Math/Test/MatrixTest.cpp

@@ -185,7 +185,10 @@ void MatrixTest::constructCopy() {
                                                Vector4(4.5f,  4.0f, 7.0f,  2.0f),
                                                Vector4(1.0f,  2.0f, 3.0f, -1.0f),
                                                Vector4(7.9f, -1.0f, 8.0f, -1.5f));
-    constexpr Matrix4x4 b(a);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be copy constexpr? */
+    constexpr
+    #endif
+    Matrix4x4 b(a);
     CORRADE_COMPARE(b, Matrix4x4(Vector4(3.0f,  5.0f, 8.0f, -3.0f),
                                  Vector4(4.5f,  4.0f, 7.0f,  2.0f),
                                  Vector4(1.0f,  2.0f, 3.0f, -1.0f),
@@ -203,7 +206,10 @@ void MatrixTest::convert() {
     constexpr Matrix3x3 c(b);
     CORRADE_COMPARE(c, b);
 
-    constexpr Mat3 d(b);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be conversion constexpr? */
+    constexpr
+    #endif
+    Mat3 d(b);
     for(std::size_t i = 0; i != 9; ++i)
         CORRADE_COMPARE(d.a[i], a.a[i]);
 

src/Magnum/Math/Test/QuaternionTest.cpp

@@ -197,7 +197,10 @@ void QuaternionTest::convert() {
     Quaternion c{a};
     CORRADE_COMPARE(c, b);
 
-    constexpr Quat d(b);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be conversion constexpr? */
+    constexpr
+    #endif
+    Quat d(b);
     CORRADE_COMPARE(d.x, a.x);
     CORRADE_COMPARE(d.y, a.y);
     CORRADE_COMPARE(d.z, a.z);

src/Magnum/Math/Test/RangeTest.cpp

@@ -284,17 +284,26 @@ void RangeTest::convert() {
     CORRADE_COMPARE(i, e);
     CORRADE_COMPARE(j, f);
 
-    constexpr Dim k(d);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be conversion constexpr? */
+    constexpr
+    #endif
+    Dim k(d);
     CORRADE_COMPARE(k.offset, a.offset);
     CORRADE_COMPARE(k.size, a.size);
 
-    constexpr Rect l(e);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be conversion constexpr? */
+    constexpr
+    #endif
+    Rect l(e);
     CORRADE_COMPARE(l.x, b.x);
     CORRADE_COMPARE(l.y, b.y);
     CORRADE_COMPARE(l.w, b.w);
     CORRADE_COMPARE(l.h, b.h);
 
-    constexpr Box m(f);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be conversion constexpr? */
+    constexpr
+    #endif
+    Box m(f);
     CORRADE_COMPARE(m.x, c.x);
     CORRADE_COMPARE(m.y, c.y);
     CORRADE_COMPARE(m.z, c.z);

src/Magnum/Math/Test/RectangularMatrixTest.cpp

@@ -246,7 +246,10 @@ void RectangularMatrixTest::convert() {
     Matrix2x3 c{a};
     CORRADE_COMPARE(c, b);
 
-    constexpr Mat2x3 d(b);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be conversion constexpr? */
+    constexpr
+    #endif
+    Mat2x3 d(b);
     for(std::size_t i = 0; i != 5; ++i)
         CORRADE_COMPARE(d.a[i], a.a[i]);
 
@@ -275,7 +278,10 @@ void RectangularMatrixTest::data() {
     constexpr Matrix3x4 a(Vector4(3.0f,  5.0f, 8.0f, 4.0f),
                           Vector4(4.5f,  4.0f, 7.0f, 3.0f),
                           Vector4(7.0f, -1.7f, 8.0f, 0.0f));
-    constexpr Vector4 b = a[2];
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+    constexpr
+    #endif
+    Vector4 b = a[2];
     constexpr Float c = a[1][2];
     constexpr Float d = *a.data();
     CORRADE_COMPARE(b, Vector4(7.0f, -1.7f, 8.0f, 0.0f));
@@ -416,13 +422,19 @@ void RectangularMatrixTest::diagonal() {
                           Vector3( 4.0f,  5.0f,  7.0f),
                           Vector3( 8.0f,  9.0f, 11.0f),
                           Vector3(12.0f, 13.0f, 15.0f));
-    constexpr Vector3 aDiagonal = a.diagonal();
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+    constexpr
+    #endif
+    Vector3 aDiagonal = a.diagonal();
     CORRADE_COMPARE(aDiagonal, diagonal);
 
     constexpr Matrix3x4 b(Vector4(-1.0f, 4.0f,  8.0f, 12.0f),
                           Vector4( 1.0f, 5.0f,  9.0f, 13.0f),
                           Vector4( 3.0f, 7.0f, 11.0f, 15.0f));
-    constexpr Vector3 bDiagonal = b.diagonal();
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+    constexpr
+    #endif
+    Vector3 bDiagonal = b.diagonal();
     CORRADE_COMPARE(bDiagonal, diagonal);
 }
 

src/Magnum/Math/Test/Vector2Test.cpp

@@ -138,7 +138,10 @@ void Vector2Test::constructConversion() {
 
 void Vector2Test::constructCopy() {
     constexpr Vector<2, Float> a(1.5f, 2.5f);
-    constexpr Vector2 b(a);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be copy constexpr? */
+    constexpr
+    #endif
+    Vector2 b(a);
     CORRADE_COMPARE(b, Vector2(1.5f, 2.5f));
 }
 
@@ -149,7 +152,10 @@ void Vector2Test::convert() {
     constexpr Vector2 c(a);
     CORRADE_COMPARE(c, b);
 
-    constexpr Vec2 d(b);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be conversion constexpr? */
+    constexpr
+    #endif
+    Vec2 d(b);
     CORRADE_COMPARE(d.x, a.x);
     CORRADE_COMPARE(d.y, a.y);
 

src/Magnum/Math/Test/Vector3Test.cpp

@@ -142,7 +142,10 @@ void Vector3Test::constructConversion() {
 
 void Vector3Test::constructCopy() {
     constexpr Vector<3, Float> a(1.0f, 2.5f, -3.0f);
-    constexpr Vector3 b(a);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be copy constexpr? */
+    constexpr
+    #endif
+    Vector3 b(a);
     CORRADE_COMPARE(b, Vector3(1.0f, 2.5f, -3.0f));
 }
 
@@ -153,7 +156,10 @@ void Vector3Test::convert() {
     constexpr Vector3 c(a);
     CORRADE_COMPARE(c, b);
 
-    constexpr Vec3 d(b);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be conversion constexpr? */
+    constexpr
+    #endif
+    Vec3 d(b);
     CORRADE_COMPARE(d.x, a.x);
     CORRADE_COMPARE(d.y, a.y);
     CORRADE_COMPARE(d.z, a.z);

src/Magnum/Math/Test/Vector4Test.cpp

@@ -105,8 +105,14 @@ void Vector4Test::construct() {
 
 void Vector4Test::constructPad() {
     constexpr Vector<2, Float> a{3.0f, -1.0f};
-    constexpr Vector4 b = Vector4::pad(a);
-    constexpr Vector4 c = Vector4::pad(a, 5.0f);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+    constexpr
+    #endif
+    Vector4 b = Vector4::pad(a);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+    constexpr
+    #endif
+    Vector4 c = Vector4::pad(a, 5.0f);
     constexpr Vector4 d = Vector4::pad(a, 5.0f, 1.0f);
     CORRADE_COMPARE(b, Vector4(3.0f, -1.0f, 0.0f, 0.0f));
     CORRADE_COMPARE(c, Vector4(3.0f, -1.0f, 5.0f, 5.0f));
@@ -151,7 +157,10 @@ void Vector4Test::constructConversion() {
 
 void Vector4Test::constructCopy() {
     constexpr Vector<4, Float> a(1.0f, -2.5f, 3.0f, 4.1f);
-    constexpr Vector4 b(a);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be copy constexpr? */
+    constexpr
+    #endif
+    Vector4 b(a);
     CORRADE_COMPARE(b, Vector4(1.0f, -2.5f, 3.0f, 4.1f));
 }
 
@@ -162,7 +171,10 @@ void Vector4Test::convert() {
     constexpr Vector4 c(a);
     CORRADE_COMPARE(c, b);
 
-    constexpr Vec4 d(b);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be conversion constexpr? */
+    constexpr
+    #endif
+    Vec4 d(b);
     CORRADE_COMPARE(d.x, a.x);
     CORRADE_COMPARE(d.y, a.y);
     CORRADE_COMPARE(d.z, a.z);

src/Magnum/Math/Test/VectorTest.cpp

@@ -256,7 +256,10 @@ void VectorTest::convert() {
     Vector3 c{a};
     CORRADE_COMPARE(c, b);
 
-    constexpr Vec3 d(b);
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Why can't be conversion constexpr? */
+    constexpr
+    #endif
+    Vec3 d(b);
     CORRADE_COMPARE(d.x, a.x);
     CORRADE_COMPARE(d.y, a.y);
     CORRADE_COMPARE(d.z, a.z);
@@ -567,8 +570,14 @@ void VectorTest::subclass() {
 
     {
         constexpr Vector<1, Float> a = 5.0f;
-        constexpr Vec2 b = Vec2::pad(a);
-        constexpr Vec2 c = Vec2::pad(a, -1.0f);
+        #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+        constexpr
+        #endif
+        Vec2 b = Vec2::pad(a);
+        #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Probably because copy is not constexpr */
+        constexpr
+        #endif
+        Vec2 c = Vec2::pad(a, -1.0f);
         CORRADE_COMPARE(b, Vec2(5.0f, 0.0f));
         CORRADE_COMPARE(c, Vec2(5.0f, -1.0f));
     }