diff --git a/doc/developer-notes.md b/doc/developer-notes.md
index 21fc360bbf..65671c6b6e 100644
--- a/doc/developer-notes.md
+++ b/doc/developer-notes.md
@@ -407,6 +407,13 @@ class A
 
   - *Rationale*: Easier to understand what is happening, thus easier to spot mistakes, even for those
   that are not language lawyers
+ - Prefer signed ints and do not mix signed and unsigned integers. If an unsigned int is used, it should have a good
+   reason. The fact a value will never be negative is not a good reason. The most common reason will be that mod two
+   arithmetic is needed, such as in cryptographic primitives. If you need to make sure that some value is always
+   a non-negative one, use an assertion or exception instead.
+   - *Rationale*: When signed ints are mixed with unsigned ints, the signed int is converted to a unsigned
+   int. If the signed int is some negative `N`, it'll become `INT_MAX - N`  which might cause unexpected consequences.
+
 
 Strings and formatting
 ------------------------