Fix compilation warnings

src/main/java/org/spongepowered/api/command/registrar/tree/CommandTreeNode.java

@@ -85,7 +85,7 @@ static CommandTreeNode<Basic> literal() {
      * @return This, for chaining.
      * @see CommandTreeNodeTypes for the node types that can be created
      */
-    T child(final String key, final CommandTreeNode.Argument<@NonNull ?> childNode);
+    T child(final String key, final CommandTreeNode.Argument<? extends @NonNull Object> childNode);
 
     /**
      * Creates a child of this node with the given key that accepts a
@@ -150,7 +150,7 @@ default <C extends CommandTreeNode.Argument<C>> T child(final String key, final
      * @param redirectTarget The node to redirect to
      * @return This, for chaining
      */
-    T redirect(CommandTreeNode<@NonNull ?> redirectTarget);
+    T redirect(CommandTreeNode<? extends @NonNull Object> redirectTarget);
 
     /**
      * Declares that this element can only be parsed by those with the given

src/main/java/org/spongepowered/api/registry/RegistryTypes.java

@@ -220,7 +220,7 @@ public final class RegistryTypes {
 
     public static final DefaultedRegistryType<EntityCategory> ENTITY_CATEGORY = RegistryTypes.spongeKeyInGame("mob_category");
 
-    public static final DefaultedRegistryType<EntityType<@NonNull ? extends Entity>> ENTITY_TYPE = RegistryTypes.minecraftKeyInGame("entity_type");
+    public static final DefaultedRegistryType<EntityType<? extends @NonNull Entity>> ENTITY_TYPE = RegistryTypes.minecraftKeyInGame("entity_type");
 
     public static final DefaultedRegistryType<Feature> FEATURE = RegistryTypes.minecraftKeyInServer("worldgen/configured_feature");
 
@@ -252,7 +252,7 @@ public final class RegistryTypes {
 
     public static final DefaultedRegistryType<PotionType> POTION_TYPE = RegistryTypes.minecraftKeyInGame("potion");
 
-    public static final DefaultedRegistryType<RecipeType<@NonNull ? extends Recipe>> RECIPE_TYPE = RegistryTypes.minecraftKeyInGame("recipe_type");
+    public static final DefaultedRegistryType<RecipeType<? extends @NonNull Recipe>> RECIPE_TYPE = RegistryTypes.minecraftKeyInGame("recipe_type");
 
     public static final DefaultedRegistryType<SoundType> SOUND_TYPE = RegistryTypes.minecraftKeyInGame("sound_event");
 
@@ -266,7 +266,7 @@ public final class RegistryTypes {
 
     public static final DefaultedRegistryType<StructureType> STRUCTURE_TYPE = RegistryTypes.minecraftKeyInGame("worldgen/structure_type");
 
-    public static final DefaultedRegistryType<Trigger<@NonNull ?>> TRIGGER = RegistryTypes.minecraftKeyInGame("trigger_type");
+    public static final DefaultedRegistryType<Trigger<? extends @NonNull Object>> TRIGGER = RegistryTypes.minecraftKeyInGame("trigger_type");
 
     public static final DefaultedRegistryType<VillagerType> VILLAGER_TYPE = RegistryTypes.minecraftKeyInGame("villager_type");
 
@@ -318,7 +318,7 @@ public final class RegistryTypes {
 
     public static final DefaultedRegistryType<CommandRegistrarType<?>> COMMAND_REGISTRAR_TYPE = RegistryTypes.spongeKeyInGame("command_registrar_type");
 
-    public static final DefaultedRegistryType<CommandTreeNodeType<@NonNull ?>> COMMAND_TREE_NODE_TYPE = RegistryTypes.spongeKeyInGame("command_tree_node_type");
+    public static final DefaultedRegistryType<CommandTreeNodeType<? extends @NonNull Object>> COMMAND_TREE_NODE_TYPE = RegistryTypes.spongeKeyInGame("command_tree_node_type");
 
     public static final DefaultedRegistryType<ComparatorMode> COMPARATOR_MODE = RegistryTypes.spongeKeyInGame("comparator_mode");
 

src/main/java/org/spongepowered/api/state/StateMatcher.java

@@ -141,7 +141,7 @@ default Builder<S, T> type(final Supplier<? extends T> type) {
          * @param stateProperty The state property
          * @return This builder, for chaining
          */
-        Builder<S, T> supportsStateProperty(StateProperty<@NonNull ?> stateProperty);
+        Builder<S, T> supportsStateProperty(StateProperty<? extends @NonNull Object> stateProperty);
 
         /**
          * Adds a {@link StateProperty} that needs to be present
@@ -154,7 +154,7 @@ default Builder<S, T> type(final Supplier<? extends T> type) {
          * @param stateProperty The state property
          * @return This builder, for chaining
          */
-        default Builder<S, T> supportsStateProperty(final Supplier<? extends StateProperty<@NonNull ?>> stateProperty) {
+        default Builder<S, T> supportsStateProperty(final Supplier<? extends StateProperty<? extends @NonNull Object>> stateProperty) {
             return this.supportsStateProperty(stateProperty.get());
         }
 

src/main/java/org/spongepowered/api/world/volume/biome/BiomeVolumeFactory.java

@@ -35,13 +35,13 @@ public interface BiomeVolumeFactory {
 
     BiomeVolume.Mutable empty(Palette<Biome, Biome> palette, RegistryReference<Biome> defaultBiome, Vector3i min, Vector3i max);
 
-    BiomeVolume.Mutable copyFromRange(BiomeVolume.Streamable<@NonNull ?> existing, Vector3i newMin, Vector3i newMax);
+    BiomeVolume.Mutable copyFromRange(BiomeVolume.Streamable<? extends @NonNull Object> existing, Vector3i newMin, Vector3i newMax);
 
-    BiomeVolume.Mutable copy(BiomeVolume.Streamable<@NonNull ?> existing);
+    BiomeVolume.Mutable copy(BiomeVolume.Streamable<? extends @NonNull Object> existing);
 
-    BiomeVolume.Immutable immutableOf(BiomeVolume.Streamable<@NonNull ?> existing);
+    BiomeVolume.Immutable immutableOf(BiomeVolume.Streamable<? extends @NonNull Object> existing);
 
-    BiomeVolume.Immutable immutableOf(BiomeVolume.Streamable<@NonNull ?> existing, Vector3i newMin, Vector3i newMax);
+    BiomeVolume.Immutable immutableOf(BiomeVolume.Streamable<? extends @NonNull Object> existing, Vector3i newMin, Vector3i newMax);
 
     UnrealizedBiomeVolume.Mutable empty(Vector3i min, Vector3i max);
 

src/main/java/org/spongepowered/api/world/volume/block/BlockVolumeFactory.java

@@ -35,12 +35,12 @@ public interface BlockVolumeFactory {
 
     BlockVolume.Mutable empty(Palette<BlockState, BlockType> palette, RegistryReference<BlockType> defaultState, Vector3i min, Vector3i max);
 
-    BlockVolume.Mutable copyFromRange(BlockVolume.Streamable<@NonNull ?> existing, Vector3i newMin, Vector3i newMax);
+    BlockVolume.Mutable copyFromRange(BlockVolume.Streamable<? extends @NonNull Object> existing, Vector3i newMin, Vector3i newMax);
 
-    BlockVolume.Mutable copy(BlockVolume.Streamable<@NonNull ?> existing);
+    BlockVolume.Mutable copy(BlockVolume.Streamable<? extends @NonNull Object> existing);
 
-    BlockVolume.Immutable immutableOf(BlockVolume.Streamable<@NonNull ?> existing);
+    BlockVolume.Immutable immutableOf(BlockVolume.Streamable<? extends @NonNull Object> existing);
 
-    BlockVolume.Immutable immutableOf(BlockVolume.Streamable<@NonNull ?> existing, Vector3i newMin, Vector3i newMax);
+    BlockVolume.Immutable immutableOf(BlockVolume.Streamable<? extends @NonNull Object> existing, Vector3i newMin, Vector3i newMax);
 
 }

src/main/java/org/spongepowered/api/world/volume/game/ChunkVolume.java

@@ -67,7 +67,7 @@ public interface ChunkVolume extends Volume {
      * @param z The z coordinate
      * @return The chunk, may be empty
      */
-    Chunk<@NonNull ?> chunk(int x, int y, int z);
+    Chunk<? extends @NonNull Object> chunk(int x, int y, int z);
 
     /**
      * Gets the loaded chunk at the given chunk coordinate position. The position
@@ -81,7 +81,7 @@ public interface ChunkVolume extends Volume {
      * @param chunkPosition The position
      * @return The chunk, if available
      */
-    default Chunk<@NonNull ?> chunk(final Vector3i chunkPosition) {
+    default Chunk<? extends @NonNull Object> chunk(final Vector3i chunkPosition) {
         Objects.requireNonNull(chunkPosition, "chunkPosition");
         return this.chunk(chunkPosition.x(), chunkPosition.y(), chunkPosition.z());
     }
@@ -92,7 +92,7 @@ public interface ChunkVolume extends Volume {
      * @param blockPosition The position
      * @return The chunk, if available
      */
-    default Chunk<@NonNull ?> chunkAtBlock(final Vector3i blockPosition) {
+    default Chunk<? extends @NonNull Object> chunkAtBlock(final Vector3i blockPosition) {
         Objects.requireNonNull(blockPosition, "blockPosition");
         return this.chunkAtBlock(blockPosition.x(), blockPosition.y(), blockPosition.z());
     }
@@ -109,7 +109,7 @@ public interface ChunkVolume extends Volume {
      * @param bz The z coordinate
      * @return The chunk, if available
      */
-    Chunk<@NonNull ?> chunkAtBlock(final int bx, final int by, final int bz);
+    Chunk<? extends @NonNull Object> chunkAtBlock(final int bx, final int by, final int bz);
 
     /**
      * Gets whether a {@link Chunk} is loaded at the particular chunk

src/main/java/org/spongepowered/api/world/volume/stream/VolumeApplicator.java

@@ -30,6 +30,6 @@
 @FunctionalInterface
 public interface VolumeApplicator<M extends MutableVolume, T, R> {
 
-    R apply(M volume, VolumeElement<@NonNull ?, T> element);
+    R apply(M volume, VolumeElement<? extends @NonNull Object, T> element);
 
 }

src/main/java/org/spongepowered/api/world/volume/stream/VolumeApplicators.java

@@ -168,7 +168,7 @@ public static <M extends PhysicsAwareMutableBlockVolume<M>> VolumeApplicator<M,
      * @return A volume applicator that applies block entity archetypes
      */
     @SuppressWarnings({"unchecked"})
-    public static <M extends BlockEntityVolume.Modifiable<M> & LocationCreator<@NonNull ?, ? extends ServerLocation>> VolumeApplicator<M, BlockEntityArchetype, Optional<? extends BlockEntity>> applyBlockEntityArchetype() {
+    public static <M extends BlockEntityVolume.Modifiable<M> & LocationCreator<? extends @NonNull Object, ? extends ServerLocation>> VolumeApplicator<M, BlockEntityArchetype, Optional<? extends BlockEntity>> applyBlockEntityArchetype() {
         return (volume, element) -> element.type().apply(volume.location(element.position().round()));
     }
 
@@ -212,7 +212,7 @@ public static <M extends BiomeVolume.Modifiable<M>> VolumeApplicator<M, Biome, B
     }
 
     @SuppressWarnings("unchecked")
-    public static <M extends EntityVolume.Modifiable<M> & LocationCreator<@NonNull ?, ? extends ServerLocation>> VolumeApplicator<M, EntityArchetype, Optional<? extends Entity>> applyEntityArchetype() {
+    public static <M extends EntityVolume.Modifiable<M> & LocationCreator<? extends @NonNull Object, ? extends ServerLocation>> VolumeApplicator<M, EntityArchetype, Optional<? extends Entity>> applyEntityArchetype() {
         return (volume, element) -> element.type().apply(volume.location(element.position()));
     }
 

src/main/java/org/spongepowered/api/world/volume/stream/VolumeElement.java

@@ -70,7 +70,7 @@ public boolean equals(final @Nullable Object o) {
                 if (o == null || this.getClass() != o.getClass()) {
                     return false;
                 }
-                final VolumeElement<@NonNull ?, ?> that = (VolumeElement<@NonNull ?, ?>) o;
+                final VolumeElement<? extends @NonNull Object, ?> that = (VolumeElement<? extends @NonNull Object, ?>) o;
                 return volume.get().equals(that.volume())
                     && type.get().equals(that.type())
                     && position.equals(that.position());