akka/akka-http

Make sure we have @implicitnotfound annotations in all relevant places

Open

#2,064 opened on Jun 12, 2018

View on GitHub
 (0 comments) (0 reactions) (0 assignees)Scala (1,311 stars) (598 forks)batch import
1 - triagedhelp wanted

Description

To make sure the compiler can give a more useful error message in case of missing implicits.

(Unfortunately this will still not help when implicit conversions themselves depend on implicit values)

Contributor guide

Tech stack
scala
Domain
developer experience
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Scala implicitsakka http codebase familiarity
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
Start by searching the akka http codebase for existing uses of the @implicitNotFound annotation. Identify implicit parameters in directives and route definitions where missing implicits could produce unclear compiler errors. Add the annotation with a helpful message to each such implicit parameter. The Scala compiler documentation explains how @implicitNotFound works. The caveat in the issue body indicates that implicit conversions themselves depend on implicit values, but that is a separate concern.