diff --git a/doc/manual/expressions/arguments-variables.xml b/doc/manual/expressions/arguments-variables.xml
index bf60cb7eef8..306d2a080bb 100644
--- a/doc/manual/expressions/arguments-variables.xml
+++ b/doc/manual/expressions/arguments-variables.xml
@@ -105,7 +105,23 @@ hello = callPackage ../applications/misc/hello/ex-1 { };
 hello = callPackage ../applications/misc/hello/ex-1 { stdenv = myStdenv; };
 </programlisting>
 
-    </para></note>
+    </para>
+
+    <para>A useful way to use the callPackage function would be to
+    change the name of the above <filename>default.nix</filename>
+    to <filename>hello.nix</filename> and create a new
+    <filename>default.nix</filename> as follows:</para>
+
+<programlisting>
+(import <nixpkgs> {}).callPackage ./hello.nix {}
+</programlisting>
+
+    <para>This infrastructure allows you to build it as a local
+    package simply by running <literal>nix-build</literal> or drop
+    into a build environment shell with
+    <literal>nix-shell</literal></para>
+
+    </note>
 
   </callout>
 
@@ -118,4 +134,4 @@ hello = callPackage ../applications/misc/hello/ex-1 { stdenv = myStdenv; };
 
 </calloutlist>
 
-</section>
\ No newline at end of file
+</section>
diff --git a/tests/lang/eval-okay-builtins-add.exp b/tests/lang/eval-okay-builtins-add.exp
new file mode 100644
index 00000000000..b55e8bce030
--- /dev/null
+++ b/tests/lang/eval-okay-builtins-add.exp
@@ -0,0 +1 @@
+[ 5 4 "int" "tt" "float" 4.0 ]
diff --git a/tests/lang/eval-okay-builtins-add.nix b/tests/lang/eval-okay-builtins-add.nix
new file mode 100644
index 00000000000..c841816222a
--- /dev/null
+++ b/tests/lang/eval-okay-builtins-add.nix
@@ -0,0 +1,8 @@
+[
+(builtins.add 2 3)
+(builtins.add 2 2)
+(builtins.typeOf (builtins.add 2  2))
+("t" + "t")
+(builtins.typeOf (builtins.add 2.0 2))
+(builtins.add 2.0 2)
+]
diff --git a/tests/lang/eval-okay-builtins-mul.exp b/tests/lang/eval-okay-builtins-mul.exp
new file mode 100644
index 00000000000..641208859c2
--- /dev/null
+++ b/tests/lang/eval-okay-builtins-mul.exp
@@ -0,0 +1 @@
+[ 4 "int" "float" 4.0 ]
diff --git a/tests/lang/eval-okay-builtins-mul.nix b/tests/lang/eval-okay-builtins-mul.nix
new file mode 100644
index 00000000000..e31258c4c1b
--- /dev/null
+++ b/tests/lang/eval-okay-builtins-mul.nix
@@ -0,0 +1,6 @@
+[
+(builtins.mul 2 2)
+(builtins.typeOf (builtins.mul 2  2))
+(builtins.typeOf (builtins.mul 2.0 2))
+(builtins.mul 2.0 2)
+]