diff --git a/function.lua b/function.lua
index 9ca29fd..12e3968 100644
--- a/function.lua
+++ b/function.lua
@@ -25,7 +25,7 @@ local function get_function_info (f)
           info.params = {}
           info.ups = {}
           info.env = debug.getfenv and debug.getfenv(f)
-          info.builtin = info.source == '=[C]'
+          info.builtin = (info.source == '=[C]')
     for i = 1, info.nparams or 0 do  info.params[i] = debug.getlocal(f, i)  end
     if info.isvararg or not info.nparams then  info.params[#info.params+1] = '...'  end
     -- Get upvalues
@@ -120,7 +120,7 @@ end
 return function (value, options, depth, l, format_value)
     local info = get_function_info(value)
 
-	if options.include_closure then
+	if options.include_closure and not info.builtin then
 		return format_function_with_closure(value, options, depth, l, format_value)
 	end
 
@@ -130,6 +130,11 @@ return function (value, options, depth, l, format_value)
         return;
     end
 
+	if info.builtin and options.short_builtins then
+		l[#l+1] = info.name
+		return;
+	end
+
     -- Include function modifier, and alignment info.
     l[#l+1] = info.builtin and 'builtin ' or ''
     l[#l+1] = { #l[#l], 'func_mod'}
diff --git a/test/test_function.lua b/test/test_function.lua
index a8d8b0e..3c9af29 100644
--- a/test/test_function.lua
+++ b/test/test_function.lua
@@ -232,7 +232,7 @@ format_test {
 format_test {
     input  = { math.cos, math.sin, math.abs },
     options = { short_builtins = true },
-    expect = '{ math.cos, math.sin, math.abs }',
+    expect = '{\n\tmath.cos,\n\tmath.sin,\n\tmath.abs\n}',
 }
 
 --------------------------------------------------------------------------------
@@ -339,6 +339,13 @@ do
 end
 
 
+format_test {
+    name    = 'Closures do not affect builtins',
+    input  = math.abs,
+    options = { more_function_info = true, include_closure = true },
+    expect = 'builtin function (x)\n\t-- math.abs\n\t-- Returns the absolute value of x.\n\n\t...\nend',
+}
+
 --------------------------------------------------------------------------------
 -- Indent functions nicely