Math: test and fix array-taking isInf()/isNan() also with vectors.

Next time I need to test properly.

src/Magnum/Math/FunctionsBatch.h

@@ -102,12 +102,12 @@ template<class T> inline auto isNan(Corrade::Containers::StridedArrayView1D<cons
 }
 
 /** @overload */
-template<class T> inline auto isNan(std::initializer_list<T> list) -> decltype(isInf(std::declval<T>())) {
+template<class T> inline auto isNan(std::initializer_list<T> list) -> decltype(isNan(std::declval<T>())) {
     return isNan<T>(Corrade::Containers::arrayView(list.begin(), list.size()));
 }
 
 /** @overload */
-template<class T, std::size_t size> inline bool isNan(const T(&array)[size]) {
+template<class T, std::size_t size> inline auto isNan(const T(&array)[size]) -> decltype(isNan(std::declval<T>())) {
     return isNan<T>(Corrade::Containers::arrayView(array));
 }
 

src/Magnum/Math/Test/FunctionsBatchTest.cpp

@@ -82,6 +82,9 @@ void FunctionsBatchTest::isInf() {
 
     const Float b[]{5.0f, -2.0f, -1.0};
     CORRADE_VERIFY(!Math::isInf(b));
+
+    Vector2 c[]{{5.0f, -3.0f}, {-2.0f, 14.0f}, {Constants::inf(), -5.0f}};
+    CORRADE_COMPARE(Math::isInf(c), BoolVector<2>{1});
 }
 
 void FunctionsBatchTest::isNan() {
@@ -103,6 +106,9 @@ void FunctionsBatchTest::isNan() {
 
     const Float b[]{5.0f, -2.0f, -1.0};
     CORRADE_VERIFY(!Math::isNan(b));
+
+    Vector2 c[]{{5.0f, -3.0f}, {14.0f, Constants::nan()}, {-2.0f, -5.0f}};
+    CORRADE_COMPARE(Math::isNan(c), BoolVector<2>{2});
 }
 
 void FunctionsBatchTest::min() {