diff --git a/spec.md b/spec.md
index 45ff57c..18cad58 100644
--- a/spec.md
+++ b/spec.md
@@ -51,7 +51,7 @@ value := 2                    # `:=` mutates the cell
 print(Num.to_str(!value))
 ```
 
-## (Almost) no function or operator overloading
+## no confusing function or operator overloading
 all operators:
 - `Num + Num` (has overloads for fixed width number types)
 - `Num - Num` (has overloads for fixed width number types)
@@ -132,6 +132,24 @@ def example6-error(): Option[Unit] {
 }
 ```
 
+## automatic return types
+```
+def add(a: Num, b: Num) -> _ {
+  a + b
+}
+```
+
+## templated generics
+```
+def [a,b] add(a: a, b: b) -> _ {
+  a + b
+}
+
+add(1,2)
+
+add(1,"2")    # error: in template expansion of add[Num,List[Char]]: No definition for `Num + List[Char]`
+```
+
 ## pattern matching
 ```
 type Option[t] = 'None | 'Some t