Get rid of some warnings

lib/geef/blob.ex

@@ -6,11 +6,11 @@ defmodule Geef.Blob do
   end
 
 
-  def size(obj = %Object{type: :blob, handle: handle}) do
+  def size(%Object{type: :blob, handle: handle}) do
     :geef_nif.blob_size(handle)
   end
 
-  def content(obj = %Object{type: :blob, handle: handle}) do
+  def content(%Object{type: :blob, handle: handle}) do
     :geef_nif.blob_content(handle)
   end
 

lib/geef/commit.ex

@@ -9,12 +9,12 @@ defmodule Geef.Commit do
   end
 
   @spec tree_id(Object.t) :: Oid.t
-  def tree_id(commit = %Object{type: :commit, handle: handle}) do
+  def tree_id(%Object{type: :commit, handle: handle}) do
     :geef_nif.commit_tree_id(handle)
   end
 
   @spec tree(t) :: {:ok, Tree.t} | {:error, any}
-  def tree(commit = %Object{type: :commit, handle: handle}) do
+  def tree(%Object{type: :commit, handle: handle}) do
     case :geef_nif.commit_tree(handle) do
       {:ok, id, handle} ->
         {:ok, %Object{type: :tree, id: id, handle: handle}}

lib/geef/index.ex

@@ -14,7 +14,7 @@ defmodule Geef.Index.Entry do
     %Geef.Index.Entry{unquote_splicing(pairs)}
   end
 
-  def to_record(e = %Geef.Index.Entry{unquote_splicing(pairs)}) do
+  def to_record(_ = %Geef.Index.Entry{unquote_splicing(pairs)}) do
     {:geef_index_entry, unquote_splicing(vals)}
   end
 

lib/geef/object.ex

@@ -14,8 +14,8 @@ defmodule Geef.Object do
 
   def lookup(repo, id, type) do
     case lookup(repo, id) do
-      {:ok, obj} ->
+      {:ok, obj = %Geef.Object{type: ^type}} ->
-        {:ok, obj = %Geef.Object{type: type}}
+        {:ok, obj}
       error ->
         error
     end

lib/geef/tag.ex

@@ -6,7 +6,7 @@ defmodule Geef.Tag do
     Object.lookup(repo, id, :tag)
   end
 
-  def peel(tag = %Object{type: :tag, handle: handle}) do
+  def peel(%Object{type: :tag, handle: handle}) do
     case :geef_nif.tag_peel(handle) do
       {:ok, type, id, peeled_handle} ->
         {:ok, %Object{type: type, id: id, handle: peeled_handle}}