diff --git a/dlib/cuda/tensor_tools.cpp b/dlib/cuda/tensor_tools.cpp
index c0f7fd69d..1099f4b4f 100644
--- a/dlib/cuda/tensor_tools.cpp
+++ b/dlib/cuda/tensor_tools.cpp
@@ -118,7 +118,7 @@ namespace dlib { namespace tt
         if (m.size() == 0 && v.size() == 0)
             return;
         DLIB_CASSERT(m.size() != 0);
-        DLIB_CASSERT(m.num_samples() == v.size());
+        DLIB_CASSERT(m.num_samples() == static_cast<long long>(v.size()));
 
 #ifdef DLIB_USE_CUDA
         cuda::scale_rows(out, m, v);
@@ -140,7 +140,7 @@ namespace dlib { namespace tt
         DLIB_CASSERT(have_same_dimensions(out,m2));
         DLIB_CASSERT(have_same_dimensions(v1,v2));
         DLIB_CASSERT(is_vector(mat(v1))); 
-        DLIB_CASSERT(v1.size() == m1.num_samples());
+        DLIB_CASSERT(static_cast<long long>(v1.size()) == m1.num_samples());
 
 #ifdef DLIB_USE_CUDA
         cuda::scale_rows2(beta, out, m1, m2, v1, v2);
diff --git a/dlib/geometry/line.h b/dlib/geometry/line.h
index c540e1f37..014630e22 100644
--- a/dlib/geometry/line.h
+++ b/dlib/geometry/line.h
@@ -210,20 +210,20 @@ namespace dlib
         const auto& v31 = v13;
         const auto& v32 = v23;
 
-        if (is_convex_quadrilateral({v01, v12, v23, v30}))
-                             return {v01, v12, v23, v30};
-        if (is_convex_quadrilateral({v01, v13, v32, v20}))
-                             return {v01, v13, v32, v20};
+        if (is_convex_quadrilateral({{v01, v12, v23, v30}}))
+                             return {{v01, v12, v23, v30}};
+        if (is_convex_quadrilateral({{v01, v13, v32, v20}}))
+                             return {{v01, v13, v32, v20}};
 
-        if (is_convex_quadrilateral({v02, v23, v31, v10}))
-                             return {v02, v23, v31, v10};
-        if (is_convex_quadrilateral({v02, v21, v13, v30}))
-                             return {v02, v21, v13, v30};
+        if (is_convex_quadrilateral({{v02, v23, v31, v10}}))
+                             return {{v02, v23, v31, v10}};
+        if (is_convex_quadrilateral({{v02, v21, v13, v30}}))
+                             return {{v02, v21, v13, v30}};
 
-        if (is_convex_quadrilateral({v03, v32, v21, v10}))
-                             return {v03, v32, v21, v10};
-        if (is_convex_quadrilateral({v03, v31, v12, v20}))
-                             return {v03, v31, v12, v20};
+        if (is_convex_quadrilateral({{v03, v32, v21, v10}}))
+                             return {{v03, v32, v21, v10}};
+        if (is_convex_quadrilateral({{v03, v31, v12, v20}}))
+                             return {{v03, v31, v12, v20}};
 
         throw no_convex_quadrilateral();
     }
diff --git a/dlib/image_transforms/interpolation.h b/dlib/image_transforms/interpolation.h
index b9eb5297c..eef353865 100644
--- a/dlib/image_transforms/interpolation.h
+++ b/dlib/image_transforms/interpolation.h
@@ -2169,8 +2169,8 @@ namespace dlib
         for (auto& p : pts)
             bounding_box += p;
 
-        const std::array<dpoint,4> corners = {bounding_box.tl_corner(), bounding_box.tr_corner(),
-                                              bounding_box.bl_corner(), bounding_box.br_corner()};
+        const std::array<dpoint,4> corners = {{bounding_box.tl_corner(), bounding_box.tr_corner(),
+                                               bounding_box.bl_corner(), bounding_box.br_corner()}};
 
         matrix<double> dists(4,4);
         for (long r = 0; r < dists.nr(); ++r)