diff --git a/src/c.jl b/src/c.jl
index f4bf578..77d5a3f 100644
--- a/src/c.jl
+++ b/src/c.jl
@@ -97,6 +97,7 @@ const ctypes = Dict{String, String}(
     "Float64" => "double",
     "Bool" => "bool",
     "RawFD" => "int",
+    "Nothing" => "void",
 
     "Cstring" => "char *",
     "Cwstring" => "wchar_t *",
@@ -105,7 +106,6 @@ const ctypes = Dict{String, String}(
     # distinct Julia types (these are just platform-specific aliases to the types above).
     "Cchar" => "char",
     "Cwchar_t" => "wchar_t",
-    "Cvoid" => "void",
     "Cint" => "int",
     "Cshort" => "short",
     "Clong" => "long",
diff --git a/test/bindinginfo_libsimple.json b/test/bindinginfo_libsimple.json
index 005e688..d004b16 100644
--- a/test/bindinginfo_libsimple.json
+++ b/test/bindinginfo_libsimple.json
@@ -1,12 +1,14 @@
 {
   "functions": [
     {
-      "symbol": "tree_size",
-      "name": "tree_size(tree::CTree{Float64})",
+      "symbol": "nothing_to_void",
+      "name": "nothing_to_void(x::Ptr{Nothing}, y::Nothing, z::Ptr{Nothing})",
       "arguments": [
-        { "name": "tree", "type_id": 1 }
+        { "name": "x", "type_id": 2 },
+        { "name": "y", "type_id": 4 },
+        { "name": "z", "type_id": 6 }
       ],
-      "returns": { "type_id": 6 }
+      "returns": { "type_id": 3 }
     },
     {
       "symbol": "copyto_and_sum",
@@ -16,64 +18,61 @@
       ],
       "returns": { "type_id": 8 }
     },
+    {
+      "symbol": "tree_size",
+      "name": "tree_size(tree::CTree{Float64})",
+      "arguments": [
+        { "name": "tree", "type_id": 11 }
+      ],
+      "returns": { "type_id": 5 }
+    },
     {
       "symbol": "countsame",
       "name": "countsame(list::Ptr{MyTwoVec}, n::Int32)",
       "arguments": [
-        { "name": "list", "type_id": 11 },
-        { "name": "n", "type_id": 4 }
+        { "name": "list", "type_id": 15 },
+        { "name": "n", "type_id": 1 }
       ],
-      "returns": { "type_id": 4 }
+      "returns": { "type_id": 1 }
     }
   ],
   "types": [
     {
       "id": 1,
-      "kind": "struct",
-      "name": "CTree{Float64}",
-      "size": 16,
-      "alignment": 8,
-      "fields": [
-        { "name": "children", "type_id": 3, "offset": 0, "isptr": false, "isfieldatomic": false }
-      ]
+      "kind": "primitive",
+      "name": "Int32",
+      "signed": true,
+      "bits": 32,
+      "size": 4,
+      "alignment": 4
     },
     {
       "id": 2,
+      "kind": "pointer",
+      "name": "Ptr{Nothing}",
+      "pointee_type_id": 3
+    },
+    {
+      "id": 3,
       "kind": "primitive",
-      "name": "Float64",
+      "name": "Nothing",
       "signed": false,
-      "bits": 64,
-      "size": 8,
-      "alignment": 8
+      "bits": 0,
+      "size": 0,
+      "alignment": 1
     },
     {
-      "id": 3,
+      "id": 4,
       "kind": "struct",
-      "name": "CVector{CTree{Float64}}",
-      "size": 16,
+      "name": "Nothing",
+      "size": 8,
       "alignment": 8,
       "fields": [
-        { "name": "length", "type_id": 4, "offset": 0, "isptr": false, "isfieldatomic": false },
-        { "name": "data", "type_id": 5, "offset": 8, "isptr": false, "isfieldatomic": false }
+        { "name": "x", "type_id": 5, "offset": 0, "isptr": false, "isfieldatomic": false }
       ]
     },
-    {
-      "id": 4,
-      "kind": "primitive",
-      "name": "Int32",
-      "signed": true,
-      "bits": 32,
-      "size": 4,
-      "alignment": 4
-    },
     {
       "id": 5,
-      "kind": "pointer",
-      "name": "Ptr{CTree{Float64}}",
-      "pointee_type_id": 1
-    },
-    {
-      "id": 6,
       "kind": "primitive",
       "name": "Int64",
       "signed": true,
@@ -81,6 +80,12 @@
       "size": 8,
       "alignment": 8
     },
+    {
+      "id": 6,
+      "kind": "pointer",
+      "name": "Ptr{Nothing}",
+      "pointee_type_id": 4
+    },
     {
       "id": 7,
       "kind": "struct",
@@ -108,7 +113,7 @@
       "size": 16,
       "alignment": 8,
       "fields": [
-        { "name": "length", "type_id": 4, "offset": 0, "isptr": false, "isfieldatomic": false },
+        { "name": "length", "type_id": 1, "offset": 0, "isptr": false, "isfieldatomic": false },
         { "name": "data", "type_id": 10, "offset": 8, "isptr": false, "isfieldatomic": false }
       ]
     },
@@ -120,19 +125,55 @@
     },
     {
       "id": 11,
+      "kind": "struct",
+      "name": "CTree{Float64}",
+      "size": 16,
+      "alignment": 8,
+      "fields": [
+        { "name": "children", "type_id": 13, "offset": 0, "isptr": false, "isfieldatomic": false }
+      ]
+    },
+    {
+      "id": 12,
+      "kind": "primitive",
+      "name": "Float64",
+      "signed": false,
+      "bits": 64,
+      "size": 8,
+      "alignment": 8
+    },
+    {
+      "id": 13,
+      "kind": "struct",
+      "name": "CVector{CTree{Float64}}",
+      "size": 16,
+      "alignment": 8,
+      "fields": [
+        { "name": "length", "type_id": 1, "offset": 0, "isptr": false, "isfieldatomic": false },
+        { "name": "data", "type_id": 14, "offset": 8, "isptr": false, "isfieldatomic": false }
+      ]
+    },
+    {
+      "id": 14,
+      "kind": "pointer",
+      "name": "Ptr{CTree{Float64}}",
+      "pointee_type_id": 11
+    },
+    {
+      "id": 15,
       "kind": "pointer",
       "name": "Ptr{MyTwoVec}",
-      "pointee_type_id": 12
+      "pointee_type_id": 16
     },
     {
-      "id": 12,
+      "id": 16,
       "kind": "struct",
       "name": "MyTwoVec",
       "size": 8,
       "alignment": 4,
       "fields": [
-        { "name": "x", "type_id": 4, "offset": 0, "isptr": false, "isfieldatomic": false },
-        { "name": "y", "type_id": 4, "offset": 4, "isptr": false, "isfieldatomic": false }
+        { "name": "x", "type_id": 1, "offset": 0, "isptr": false, "isfieldatomic": false },
+        { "name": "y", "type_id": 1, "offset": 4, "isptr": false, "isfieldatomic": false }
       ]
     }
   ]
diff --git a/test/runtests.jl b/test/runtests.jl
index 32790a6..cb7ba4a 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -180,6 +180,7 @@ end
             @test occursin("CVector_Float32 to;", content)
             @test occursin("float copyto_and_sum(CVectorPair_Float32 fromto);", content)
             @test occursin("int32_t countsame(MyTwoVec* list, int32_t n);", content)
+            @test occursin("void nothing_to_void(void* x, Nothing y, Nothing* z);", content)
         end
     end
 end