GL: verify that NoCreate constructors are explicit.

src/Magnum/GL/Test/AbstractShaderProgramTest.cpp

@@ -50,7 +50,8 @@ void AbstractShaderProgramTest::constructNoCreate() {
         CORRADE_COMPARE(shader.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, AbstractShaderProgram>::value));
 }
 
 void AbstractShaderProgramTest::constructCopy() {

src/Magnum/GL/Test/BufferImageTest.cpp

@@ -53,7 +53,8 @@ void BufferImageTest::constructNoCreate() {
         CORRADE_COMPARE(image.buffer().id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, BufferImage2D>::value));
 }
 
 void BufferImageTest::constructNoCreateCompressed() {

src/Magnum/GL/Test/BufferTest.cpp

@@ -61,7 +61,8 @@ void BufferTest::constructNoCreate() {
         CORRADE_COMPARE(buffer.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, Buffer>::value));
 }
 
 void BufferTest::constructCopy() {

src/Magnum/GL/Test/BufferTextureTest.cpp

@@ -47,7 +47,8 @@ void BufferTextureTest::constructNoCreate() {
         CORRADE_COMPARE(texture.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, BufferTexture>::value));
 }
 
 void BufferTextureTest::constructCopy() {

src/Magnum/GL/Test/ContextTest.cpp

@@ -78,6 +78,9 @@ void ContextTest::constructNoCreate() {
     }
 
     CORRADE_VERIFY(!Context::hasCurrent());
+
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, Context>::value));
 }
 
 void ContextTest::constructCopyMove() {

src/Magnum/GL/Test/CubeMapTextureArrayTest.cpp

@@ -47,7 +47,8 @@ void CubeMapTextureArrayTest::constructNoCreate() {
         CORRADE_COMPARE(texture.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, CubeMapTextureArray>::value));
 }
 
 void CubeMapTextureArrayTest::constructCopy() {

src/Magnum/GL/Test/CubeMapTextureTest.cpp

@@ -47,7 +47,8 @@ void CubeMapTextureTest::constructNoCreate() {
         CORRADE_COMPARE(texture.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, CubeMapTexture>::value));
 }
 
 void CubeMapTextureTest::constructCopy() {

src/Magnum/GL/Test/FramebufferTest.cpp

@@ -53,7 +53,8 @@ void FramebufferTest::constructNoCreate() {
         CORRADE_COMPARE(framebuffer.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, Framebuffer>::value));
 }
 
 void FramebufferTest::constructCopy() {

src/Magnum/GL/Test/MeshTest.cpp

@@ -89,7 +89,8 @@ void MeshTest::constructNoCreate() {
         CORRADE_COMPARE(mesh.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, Mesh>::value));
 }
 
 void MeshTest::constructViewNoCreate() {
@@ -99,7 +100,8 @@ void MeshTest::constructViewNoCreate() {
         CORRADE_COMPARE(&view.mesh(), &mesh);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, MeshView>::value));
 }
 
 void MeshTest::constructCopy() {

src/Magnum/GL/Test/MultisampleTextureTest.cpp

@@ -53,7 +53,8 @@ void MultisampleTextureTest::construct2DNoCreate() {
         CORRADE_COMPARE(texture.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, MultisampleTexture2D>::value));
 }
 
 void MultisampleTextureTest::construct2DArrayNoCreate() {
@@ -62,7 +63,8 @@ void MultisampleTextureTest::construct2DArrayNoCreate() {
         CORRADE_COMPARE(texture.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, MultisampleTexture2DArray>::value));
 }
 
 void MultisampleTextureTest::constructCopy2D() {

src/Magnum/GL/Test/PipelineStatisticsQueryTest.cpp

@@ -47,7 +47,8 @@ void PipelineStatisticsQueryTest::constructNoCreate() {
         CORRADE_COMPARE(query.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, PipelineStatisticsQuery>::value));
 }
 
 void PipelineStatisticsQueryTest::constructCopy() {

src/Magnum/GL/Test/PrimitiveQueryTest.cpp

@@ -47,7 +47,8 @@ void PrimitiveQueryTest::constructNoCreate() {
         CORRADE_COMPARE(query.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, PrimitiveQuery>::value));
 }
 
 void PrimitiveQueryTest::constructCopy() {

src/Magnum/GL/Test/RectangleTextureTest.cpp

@@ -47,7 +47,8 @@ void RectangleTextureTest::constructNoCreate() {
         CORRADE_COMPARE(texture.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, RectangleTexture>::value));
 }
 
 void RectangleTextureTest::constructCopy() {

src/Magnum/GL/Test/RenderbufferTest.cpp

@@ -47,7 +47,8 @@ void RenderbufferTest::constructNoCreate() {
         CORRADE_COMPARE(renderbuffer.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, Renderbuffer>::value));
 }
 
 void RenderbufferTest::constructCopy() {

src/Magnum/GL/Test/SampleQueryTest.cpp

@@ -47,7 +47,8 @@ void SampleQueryTest::constructNoCreate() {
         CORRADE_COMPARE(query.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, SampleQuery>::value));
 }
 
 void SampleQueryTest::constructCopy() {

src/Magnum/GL/Test/ShaderTest.cpp

@@ -51,7 +51,8 @@ void ShaderTest::constructNoCreate() {
         CORRADE_COMPARE(shader.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, Shader>::value));
 }
 
 void ShaderTest::constructCopy() {

src/Magnum/GL/Test/TextureArrayTest.cpp

@@ -63,7 +63,8 @@ void TextureArrayTest::construct1DNoCreate() {
         CORRADE_COMPARE(texture.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, Texture1DArray>::value));
 }
 #endif
 
@@ -73,7 +74,8 @@ void TextureArrayTest::construct2DNoCreate() {
         CORRADE_COMPARE(texture.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, Texture2DArray>::value));
 }
 
 #ifndef MAGNUM_TARGET_GLES

src/Magnum/GL/Test/TextureTest.cpp

@@ -76,7 +76,8 @@ void TextureTest::construct1DNoCreate() {
         CORRADE_COMPARE(texture.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, Texture1D>::value));
 }
 #endif
 
@@ -86,7 +87,8 @@ void TextureTest::construct2DNoCreate() {
         CORRADE_COMPARE(texture.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, Texture2D>::value));
 }
 
 #if !(defined(MAGNUM_TARGET_WEBGL) && defined(MAGNUM_TARGET_GLES2))
@@ -96,7 +98,8 @@ void TextureTest::construct3DNoCreate() {
         CORRADE_COMPARE(texture.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, Texture3D>::value));
 }
 #endif
 

src/Magnum/GL/Test/TimeQueryTest.cpp

@@ -47,7 +47,8 @@ void TimeQueryTest::constructNoCreate() {
         CORRADE_COMPARE(query.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, TimeQuery>::value));
 }
 
 void TimeQueryTest::constructCopy() {

src/Magnum/GL/Test/TransformFeedbackTest.cpp

@@ -47,7 +47,8 @@ void TransformFeedbackTest::constructNoCreate() {
         CORRADE_COMPARE(xfb.id(), 0);
     }
 
-    CORRADE_VERIFY(true);
+    /* Implicit construction is not allowed */
+    CORRADE_VERIFY(!(std::is_convertible<NoCreateT, TransformFeedback>::value));
 }
 
 void TransformFeedbackTest::constructCopy() {