golang/go

cmd/compile: clearer error message for unkeyed composite literal with unexported field

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#28,053 opened on Oct 6, 2018

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 (13 comments) (0 reactions) (1 assignee)Go (19,008 forks)batch import
BadErrorMessageFixPendingcompiler/runtimehelp wanted

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Description

I have a struct:

package df

type SortKey struct {
	Key interface{}
	SortDesc bool
	seriesIndex int
}

From an outside package:

TRY 1

z := df.SortKey{"n", false}

Compiler error: too few values in df.SortKey literal

TRY 2

z := df.SortKey{"n", false, 0}

Compiler error: implicit assignment of unexported field 'seriesIndex' in df.SortKey literal

You can't win. Perhaps it should just be disallowed for Go 2 - It messes up backwards compatibility anyway amongst minor versions of packages (eg. net/http.Request and Context situation).

Contributor guide

Research direction
Investigate the Go compiler source code to locate where composite literal errors are generated (e.g., in typecheck or noder). Trace the logic that produces 'too few values' and 'implicit assignment of unexported field' messages, and propose a unified error that covers both cases.
Tech stack
go
Domain
backenddeveloper experience
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Gocompiler internals
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70