6 files changed, 21 insertions, 13 deletions
diff --git a/src/resources/imagehelper.cpp b/src/resources/imagehelper.cpp
index e49a738f2..18e415972 100644
--- a/src/resources/imagehelper.cpp
+++ b/src/resources/imagehelper.cpp
@@ -86,6 +86,9 @@ Image *ImageHelper::load(SDL_RWops *const rw, Dye const &dye)
         tmpImage, &rgba, SDL_SWSURFACE);
     MSDL_FreeSurface(tmpImage);
 
+    if (!surf)
+        return nullptr;
+
     uint32_t *const pixels = static_cast<uint32_t *const>(surf->pixels);
     const int type = dye.getType();
 
diff --git a/src/resources/map/mapitem.cpp b/src/resources/map/mapitem.cpp
index f1d045e7f..44f3ec889 100644
--- a/src/resources/map/mapitem.cpp
+++ b/src/resources/map/mapitem.cpp
@@ -164,15 +164,12 @@ void MapItem::draw(Graphics *const graphics, const int x, const int y,
         && mType != MapItemType::EMPTY)
     {
         Font *const font = gui->getFont();
-        if (font)
-        {
-            const Color &color = userPalette->getColor(UserColorId::BEING);
-            font->drawString(graphics,
-                color,
-                color,
-                mName,
-                x, y);
-        }
+        const Color &color = userPalette->getColor(UserColorId::BEING);
+        font->drawString(graphics,
+            color,
+            color,
+            mName,
+            x, y);
     }
     BLOCK_END("MapItem::draw")
 }
diff --git a/src/resources/mapreader.cpp b/src/resources/mapreader.cpp
index 54ee95ea5..f2ec5633d 100644
--- a/src/resources/mapreader.cpp
+++ b/src/resources/mapreader.cpp
@@ -497,7 +497,7 @@ inline static void setTile(Map *const map,
                            const MapLayer::Type &layerType,
                            MapHeights *const heights,
                            const int x, const int y,
-                           const int gid) A_NONNULL(1, 4);
+                           const int gid) A_NONNULL(1);
 
 inline static void setTile(Map *const map,
                            MapLayer *const layer,
@@ -556,9 +556,9 @@ inline static void setTile(Map *const map,
 
         case MapLayer::HEIGHTS:
         {
-            if (!set)
+            if (!set || !heights)
                 break;
-            if (map->getVersion() >= 2)
+            if (heights && map->getVersion() >= 2)
             {
                 heights->setHeight(x, y, static_cast<uint8_t>(
                     gid - set->getFirstGid() + 1));
diff --git a/src/resources/openglimagehelper.cpp b/src/resources/openglimagehelper.cpp
index ca553a180..bf051fc0c 100644
--- a/src/resources/openglimagehelper.cpp
+++ b/src/resources/openglimagehelper.cpp
@@ -67,6 +67,8 @@ Image *OpenGLImageHelper::load(SDL_RWops *const rw, Dye const &dye)
 
     SDL_Surface *const surf = convertTo32Bit(tmpImage);
     MSDL_FreeSurface(tmpImage);
+    if (!surf)
+        return nullptr;
 
     uint32_t *pixels = static_cast<uint32_t *>(surf->pixels);
     const int type = dye.getType();
@@ -291,6 +293,8 @@ Image *OpenGLImageHelper::glLoad(SDL_Surface *tmpImage,
 
     SDL_Surface *oldImage = tmpImage;
     tmpImage = convertSurfaceNormalize(tmpImage, width, height);
+    if (!tmpImage)
+        return nullptr;
 
     const int realWidth = tmpImage->w;
     const int realHeight = tmpImage->h;
@@ -438,6 +442,8 @@ void OpenGLImageHelper::copySurfaceToImage(const Image *const image,
 
     SDL_Surface *const oldSurface = surface;
     surface = convertSurface(surface, surface->w, surface->h);
+    if (!surface)
+        return;
 
     mglTextureSubImage2D(image->mGLImage,
         mTextureType, 0,
diff --git a/src/resources/resourcemanager.h b/src/resources/resourcemanager.h
index cb55f4d6e..9d954cf50 100644
--- a/src/resources/resourcemanager.h
+++ b/src/resources/resourcemanager.h
@@ -223,7 +223,7 @@ class ResourceManager final
          * Returns an instance of the class, creating one if it does not
          * already exist.
          */
-        static ResourceManager *getInstance() A_WARN_UNUSED;
+        static ResourceManager *getInstance() RETURNS_NONNULL A_WARN_UNUSED;
 
         /**
          * Deletes the class instance if it exists.
diff --git a/src/resources/sdlimagehelper.cpp b/src/resources/sdlimagehelper.cpp
index 38939269f..e0018b868 100644
--- a/src/resources/sdlimagehelper.cpp
+++ b/src/resources/sdlimagehelper.cpp
@@ -71,6 +71,8 @@ Image *SDLImageHelper::load(SDL_RWops *const rw, Dye const &dye)
     SDL_Surface *const surf = MSDL_ConvertSurface(
         tmpImage, &rgba, SDL_SWSURFACE);
     MSDL_FreeSurface(tmpImage);
+    if (!surf)
+        return nullptr;
 
     uint32_t *pixels = static_cast<uint32_t *>(surf->pixels);
     const int type = dye.getType();