wire: wire.Value is not forbidding references to names introduced in function scope about wire

[vangent]

The README for wire says "It's important to note that the expression will be copied to the injector's package; references to variables will be evaluated during the injector package's initialization." So maybe this is not supported? The error message could be better.

[zombiezen]

Link for sample is broken, and the imports are really relevant here. This sounds like a legit bug, though (the Wire value initialization time stuff is pretty now). Can you check that link?

[vangent]

The new testcase MultipleSimilarPackages is easily modified to demonstrate this:

vangent/go-cloud@ecd11e6#diff-08ca43f68146628973a3c5efdcb374e7

[zombiezen]

Ohhh. The issue is that Wire is not forbidding references to names introduced in function scope. Wire should throw an error in this case and not generate the code. I modified the issue description to make this more clear.

[vangent]

Yea, the README explicitly says it's not supported but the error message doesn't tell you what you did wrong.

Why can't we support this?

[zombiezen]

It is technically feasible, but it makes the rule of "wire.Value is for constants" no longer true, and thus more complex to the user.