Trade: and you, MSVC 2015, need a special place in hell.

src/Magnum/Trade/MaterialData.h

@@ -2636,7 +2636,17 @@ template<class T
     #ifndef DOXYGEN_GENERATING_OUTPUT
     , class
     #endif
-> constexpr MaterialAttributeData::MaterialAttributeData(const Containers::StringView name, const T& value) noexcept: _data{Implementation::MaterialAttributeTypeFor<T>::type(), (CORRADE_CONSTEXPR_ASSERT(name.size() + sizeof(T) + 2 <= Implementation::MaterialAttributeDataSize, "Trade::MaterialAttributeData: name" << name << "too long, expected at most" << Implementation::MaterialAttributeDataSize - sizeof(T) - 2 << "bytes for" << Implementation::MaterialAttributeTypeFor<T>::type() << "but got" << name.size()), name), value} {}
+> constexpr MaterialAttributeData::MaterialAttributeData(const Containers::StringView name, const T& value) noexcept:
+    _data{Implementation::MaterialAttributeTypeFor<T>::type(),
+        /* MSVC 2015 complains about "error C2065: 'T': undeclared identifier"
+           in the lambda inside this macro. Sorry, the assert will be less
+           useful on that stupid thing. */
+        #ifndef CORRADE_MSVC2015_COMPATIBILITY
+        (CORRADE_CONSTEXPR_ASSERT(name.size() + sizeof(T) + 2 <= Implementation::MaterialAttributeDataSize, "Trade::MaterialAttributeData: name" << name << "too long, expected at most" << Implementation::MaterialAttributeDataSize - sizeof(T) - 2 << "bytes for" << Implementation::MaterialAttributeTypeFor<T>::type() << "but got" << name.size()), name)
+        #else
+        (CORRADE_CONSTEXPR_ASSERT(name.size() + sizeof(T) + 2 <= Implementation::MaterialAttributeDataSize, "Trade::MaterialAttributeData: name" << name << "too long, got" << name.size() << "bytes"), name)
+        #endif
+    , value} {}
 
 /* The 4 extra bytes are for a null byte after both the name and value, a type
    and a string size */

src/Magnum/Trade/Test/MaterialDataTest.cpp

@@ -821,11 +821,18 @@ void MaterialDataTest::constructAttributeTooLarge() {
     Error redirectError{&out};
     MaterialAttributeData{"attributeIsLong", Matrix3x4{}};
     /* Constexpr variant has the same assert, but in the header. It should have
-       the same output. */
+       the same output. Except on MSVC 2015, which is a crap thing and gets
+       lost when encountering T in there, so the assert is less useful. */
     /*constexpr*/ MaterialAttributeData{"attributeIsLong"_s, Matrix3x4{}};
+    #ifndef CORRADE_MSVC2015_COMPATIBILITY
     CORRADE_COMPARE(out.str(),
         "Trade::MaterialAttributeData: name attributeIsLong too long, expected at most 14 bytes for Trade::MaterialAttributeType::Matrix3x4 but got 15\n"
         "Trade::MaterialAttributeData: name attributeIsLong too long, expected at most 14 bytes for Trade::MaterialAttributeType::Matrix3x4 but got 15\n");
+    #else
+    CORRADE_COMPARE(out.str(),
+        "Trade::MaterialAttributeData: name attributeIsLong too long, expected at most 14 bytes for Trade::MaterialAttributeType::Matrix3x4 but got 15\n"
+        "Trade::MaterialAttributeData: name attributeIsLong too long, got 15 bytes\n");
+    #endif
 }
 
 void MaterialDataTest::constructAttributeTooLargeString() {