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btracey opened this issue Jan 10, 2014 · 7 comments
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go/parser: confusing error message with missing "range" in for loop #7102

btracey opened this issue Jan 10, 2014 · 7 comments
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Go1.3

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@btracey
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btracey commented Jan 10, 2014 

Relevant code:
http://play.golang.org/p/V_0vWTl3KE

Trying to range over anonymous structs but forgetting the range command, 
"for _, test := []struct{ " ...

Hitting "run" produces a  nice error message, 
"prog.go:6: assignment count mismatch: 2 = 1
prog.go:6: i, test := []struct { i int } literal used as value"

However, running format produces a much more cryptic message "6:6: expected
condition, found simple statement".  I get a similar error message running "go
test".
@minux
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minux commented Jan 10, 2014

Comment 1:

we probably can do better here. leaving to gri.
btw, go test first uses go/parser to parse the source, so it outputs the same
error message as gofmt.

Labels changed: added release-go1.3maybe, repo-main.

Owner changed to @griesemer.

@btracey
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btracey commented Jan 10, 2014

Comment 2:

Thanks for the info. Is there a reason that the error messages from gc couldn't or
shouldn't be the same as those from go/parser?

@griesemer
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Comment 3:

The parser is a different tool. The error messages are not synchronized. Some are better
in gc, some are better in go/parser.

@btracey
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btracey commented Jan 10, 2014

Comment 4:

To rephrase my question, isn't it a desirable property that they have the same messages?

@griesemer
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Comment 5:

It's desirable but not easily possible. gc is using yacc, the go/parser is parsing in
recursive-descent fashion. That said, this issue is not the right place to discuss this.

@griesemer
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Comment 6:

https://golang.org/cl/56770045

Status changed to Started.

@griesemer
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Comment 7:

This issue was closed by revision 947aaf2.

Status changed to Fixed.

@rsc rsc added this to the Go1.3 milestone Apr 14, 2015
@golang golang locked and limited conversation to collaborators Jun 25, 2016
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@rsc @minux @btracey @griesemer @gopherbot