diff --git a/doc/changelog.dox b/doc/changelog.dox
index 2ae116cac..025d72034 100644
--- a/doc/changelog.dox
+++ b/doc/changelog.dox
@@ -155,7 +155,7 @@ See also:
 
 @subsubsection changelog-latest-changes-shaders Shaders library
 
--   @ref Shaders::Phong::bindAmbientTexture(),
+-   @ref Shaders::Flat::bindTexture(), @ref Shaders::Phong::bindAmbientTexture(),
     @ref Shaders::Phong::bindDiffuseTexture(),
     @ref Shaders::Phong::bindSpecularTexture() and
     @ref Shaders::Phong::bindTextures() now assert that the shader was created
@@ -254,7 +254,7 @@ See also:
     working to fail with an assertion. See the new
     @ref Math::Matrix3::rotationShear() and @ref Math::Matrix4::rotationShear()
     accessors for a possible solution.
--   @ref Shaders::Phong::bindAmbientTexture(),
+-   @ref Shaders::Flat::bindTexture(), @ref Shaders::Phong::bindAmbientTexture(),
     @ref Shaders::Phong::bindDiffuseTexture(),
     @ref Shaders::Phong::bindSpecularTexture() and
     @ref Shaders::Phong::bindTextures() now assert that the shader was created
diff --git a/src/Magnum/Shaders/CMakeLists.txt b/src/Magnum/Shaders/CMakeLists.txt
index 6d96f27d4..7c30a098d 100644
--- a/src/Magnum/Shaders/CMakeLists.txt
+++ b/src/Magnum/Shaders/CMakeLists.txt
@@ -29,7 +29,6 @@ set_target_properties(MagnumShaders_RCS-dependencies PROPERTIES FOLDER "Magnum/S
 set(MagnumShaders_SRCS
     AbstractVector.cpp
     DistanceFieldVector.cpp
-    Flat.cpp
     MeshVisualizer.cpp
     Vector.cpp
     VertexColor.cpp
@@ -37,6 +36,7 @@ set(MagnumShaders_SRCS
     ${MagnumShaders_RCS})
 
 set(MagnumShaders_GracefulAssert_SRCS
+    Flat.cpp
     Phong.cpp)
 
 set(MagnumShaders_HEADERS
diff --git a/src/Magnum/Shaders/Flat.cpp b/src/Magnum/Shaders/Flat.cpp
index beb3bd947..936ea31f4 100644
--- a/src/Magnum/Shaders/Flat.cpp
+++ b/src/Magnum/Shaders/Flat.cpp
@@ -106,7 +106,9 @@ template<UnsignedInt dimensions> Flat<dimensions>::Flat(const Flags flags): _fla
 }
 
 template<UnsignedInt dimensions> Flat<dimensions>& Flat<dimensions>::bindTexture(GL::Texture2D& texture) {
-    if(_flags & Flag::Textured)  texture.bind(TextureLayer);
+    CORRADE_ASSERT(_flags & Flag::Textured,
+        "Shaders::Flat::bindTexture(): the shader was not created with texturing enabled", *this);
+    texture.bind(TextureLayer);
     return *this;
 }
 
diff --git a/src/Magnum/Shaders/Flat.h b/src/Magnum/Shaders/Flat.h
index 8be0055fa..a08c6018d 100644
--- a/src/Magnum/Shaders/Flat.h
+++ b/src/Magnum/Shaders/Flat.h
@@ -186,7 +186,8 @@ template<UnsignedInt dimensions> class MAGNUM_SHADERS_EXPORT Flat: public GL::Ab
          * @brief Bind texture
          * @return Reference to self (for method chaining)
          *
-         * Has effect only if @ref Flag::Textured is set.
+         * Expects that the shader was created with @ref Flag::Textured
+         * enabled.
          * @see @ref setColor()
          */
         Flat<dimensions>& bindTexture(GL::Texture2D& texture);
diff --git a/src/Magnum/Shaders/Test/CMakeLists.txt b/src/Magnum/Shaders/Test/CMakeLists.txt
index a0a604500..23732dd55 100644
--- a/src/Magnum/Shaders/Test/CMakeLists.txt
+++ b/src/Magnum/Shaders/Test/CMakeLists.txt
@@ -41,7 +41,7 @@ set_target_properties(
 
 if(BUILD_GL_TESTS)
     corrade_add_test(ShadersDistanceFieldVectorGLTest DistanceFieldVectorGLTest.cpp LIBRARIES MagnumShaders MagnumOpenGLTester)
-    corrade_add_test(ShadersFlatGLTest FlatGLTest.cpp LIBRARIES MagnumShaders MagnumOpenGLTester)
+    corrade_add_test(ShadersFlatGLTest FlatGLTest.cpp LIBRARIES MagnumShadersTestLib MagnumOpenGLTester)
     corrade_add_test(ShadersMeshVisualizerGLTest MeshVisualizerGLTest.cpp LIBRARIES MagnumShaders MagnumOpenGLTester)
     corrade_add_test(ShadersPhongGLTest PhongGLTest.cpp LIBRARIES MagnumShadersTestLib MagnumOpenGLTester)
     corrade_add_test(ShadersVectorGLTest VectorGLTest.cpp LIBRARIES MagnumShaders MagnumOpenGLTester)
diff --git a/src/Magnum/Shaders/Test/FlatGLTest.cpp b/src/Magnum/Shaders/Test/FlatGLTest.cpp
index c9fd62ae3..585779dd3 100644
--- a/src/Magnum/Shaders/Test/FlatGLTest.cpp
+++ b/src/Magnum/Shaders/Test/FlatGLTest.cpp
@@ -23,8 +23,13 @@
     DEALINGS IN THE SOFTWARE.
 */
 
+#include <sstream>
 #include <Corrade/Utility/Format.h>
 
+#include "Magnum/ImageView.h"
+#include "Magnum/PixelFormat.h"
+#include "Magnum/GL/Texture.h"
+#include "Magnum/GL/TextureFormat.h"
 #include "Magnum/GL/OpenGLTester.h"
 #include "Magnum/Shaders/Flat.h"
 
@@ -36,6 +41,9 @@ struct FlatGLTest: GL::OpenGLTester {
     template<UnsignedInt dimensions> void construct();
 
     template<UnsignedInt dimensions> void constructMove();
+
+    template<UnsignedInt dimensions> void bindTexture();
+    template<UnsignedInt dimensions> void bindTextureNotEnabled();
 };
 
 namespace {
@@ -58,7 +66,12 @@ FlatGLTest::FlatGLTest() {
 
     addTests<FlatGLTest>({
         &FlatGLTest::constructMove<2>,
-        &FlatGLTest::constructMove<3>});
+        &FlatGLTest::constructMove<3>,
+
+        &FlatGLTest::bindTexture<2>,
+        &FlatGLTest::bindTexture<3>,
+        &FlatGLTest::bindTextureNotEnabled<2>,
+        &FlatGLTest::bindTextureNotEnabled<3>});
 }
 
 template<UnsignedInt dimensions> void FlatGLTest::construct() {
@@ -96,6 +109,40 @@ template<UnsignedInt dimensions> void FlatGLTest::constructMove() {
     CORRADE_VERIFY(!b.id());
 }
 
+template<UnsignedInt dimensions> void FlatGLTest::bindTexture() {
+    setTestCaseName(Utility::formatString("bindTexture<{}>", dimensions));
+
+    char data[4];
+
+    GL::Texture2D texture;
+    texture
+        .setMinificationFilter(SamplerFilter::Linear, SamplerMipmap::Linear)
+        .setMagnificationFilter(SamplerFilter::Linear)
+        .setWrapping(SamplerWrapping::ClampToEdge)
+        .setImage(0, GL::TextureFormat::RGBA, ImageView2D{PixelFormat::RGBA8Unorm, {1, 1}, data});
+
+    MAGNUM_VERIFY_NO_GL_ERROR();
+
+    /* Test just that no assertion is fired */
+    Flat<dimensions> shader{Flat<dimensions>::Flag::Textured};
+    shader.bindTexture(texture);
+
+    MAGNUM_VERIFY_NO_GL_ERROR();
+}
+
+template<UnsignedInt dimensions> void FlatGLTest::bindTextureNotEnabled() {
+    setTestCaseName(Utility::formatString("bindTextureNotEnabled<{}>", dimensions));
+
+    std::ostringstream out;
+    Error redirectError{&out};
+
+    GL::Texture2D texture;
+    Flat<dimensions> shader;
+    shader.bindTexture(texture);
+
+    CORRADE_COMPARE(out.str(), "Shaders::Flat::bindTexture(): the shader was not created with texturing enabled\n");
+}
+
 }}}
 
 CORRADE_TEST_MAIN(Magnum::Shaders::Test::FlatGLTest)