text/template: cannot index with literal integer from map[int32]string

[bupjae]

What version of Go are you using (go version)?

go1.8

What operating system and processor architecture are you using (go env)?

(go playground)

What did you do?

https://play.golang.org/p/dMKNy4pTnb

What did you expect to see?

[ ok] Element 0 is zero
[ ok] Element 0 is zero
[ ok] Element 0 is zero

What did you see instead?

[ ok] Element 0 is zero
[ ok] Element 0 is zero
[err] template: :1:15: executing "" at <index . 0>: error calling index: value has type int; should be int32 

I think "untyped" integer in template should become not only "int", but also "int32", "int64", ......

[odeke-em]

/cc @robpike @rsc

• text/template documents this
  as predefined global function

index
	Returns the result of indexing its first argument by the
	following arguments. Thus "index x 1 2 3" is, in Go syntax,
	x[1][2][3]. Each indexed item must be a map, slice, or array.

must be a map so no restriction on the typing, IMO should be fixed as per this bug report.

• Also an additional note is that "html/template" has the same functionality but predefined global functions are not documented for "html/template" as per https://play.golang.org/p/Gf9Ez_QEyY.

[rsc]

This is just a bug. Constants are supposed to be ideal-like and should convert to int32 here.

[bradfitz]

Or, if somebody has an easy fix this week, Go 1.9 is fine too.

[gopherbot]

CL https://golang.org/cl/43850 mentions this issue.

[odeke-em]

Cool, thanks for the information, for starters, I've mailed https://go-review.googlesource.com/43850.

[odeke-em]

I mailed a CL for Go1.9 on that day as per #20439 (comment). Should we instead mark it as for Go1.10?