cmd/vet: warn about unused struct or array, ignoring assignment to field or element · golang/go#449

2009-12-22T02:14:21.000Z

by **RyanneDolan**: What steps will reproduce the problem? v := new(struct{i int}) v.i = 1 What is the expected output? What do you see instead? Should get "v declared and not used" error. Instead, compiles fine. What is your $GOOS? $GOARCH? linux/386 Which revision are you using? (hg identify) 54392bd03d06 tip Please provide any additional information below. The dot operator should mark its left operand as "used" only when it appears on the RHS. a = 1 // 'a' is not marked as used (CORRECT) v.i = 1 // 'v' is marked as used (WRONG) a = v.i // 'v' is marked as used (CORRECT) This bug is important to fix for consistency, and because it confuses new programmers who might expect reference semantics: for _,v := range arr {v.i = 1} // doesn't do anything Mentioned here: http://groups.google.com/group/golang- nuts/browse_thread/thread/342fe61c78916496/fbb57f693f1aca72

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AnalysisNeedsFixhelp wanted

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by RyanneDolan:

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Research direction: Inspect the cmd/vet tool's code to find where assignments to struct fields or array elements mark the left operand as used, and modify it to only mark as used when the expression appears on the right hand side.
Tech stack: go
Domain: backend
Issue type: Bug
Difficulty: 2
Estimated time: 1-3 hours
Activity status: Active
Clarity: Clear
Prerequisites: Go
Newbie friendliness: 60

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