MIR: Fix value moved diagnose messages

[ritiek]

#45960. I believe this will take a different approach. Simply replacing all nouns to verbs (desired_action) messes up the message use of moved value (although fixes the message in original issue). Here is what happens:

$ rustc -Zborrowck-mir src/test/ui/borrowck/borrowck-reinit.rs

error[E0382]: used of moved value: `x` (Mir)
  --> src/test/ui/borrowck/borrowck-reinit.rs:18:16
   |
17 |     drop(x);
   |          - value moved here
18 |     let _ = (1,x);
   |                ^ value used here after move

error: aborting due to 2 previous errors

(Notice: "used of moved value: x" instead of "use")

Which does not seem to be okay.

After experimenting a bit, it looks like report_use_of_moved_value() tries to handle both these messages by taking in only one form ofdesired_action.

These messages rise from: "{noun} of moved value" and "value {verb} here after move".

This PR fixes "value {verb} here after move" type messages by passing a corresponding verb (desired_action) instead of the original noun.

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @arielb1 (or someone else) soon.

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[ritiek]

cc @kennytm

[kennytm]

Perhaps change this branch to unreachable!() or span_bug!(...).

[kennytm]

cc @pnkfelix.

Personally I'd create an enum so that the unreachable branch won't appear at all, but that will introduce a lot of changes just for a grammatical fix.

#[derive(Copy, Clone)]
enum DesiredAction {
    Update,
    Borrow,
    Use,
    Assignment,
}
impl DesiredAction {
    fn as_noun(self) -> &'static str {
        match self {
            DesiredAction::Update => "update",
            ...
        }
    }
    fn as_verb_in_past_tense(self) -> &'static str {
        match self {
            DesiredAction::Update => "updated",
            ...
        }
    }
}

[bors]

☔ The latest upstream changes (presumably #46116) made this pull request unmergeable. Please resolve the merge conflicts.

[ritiek]

I've replaced the branch with span_bug!, not sure if it is correct though. An enum would introduce a lot of changes indeed but I'll wait for the final call.

[arielb1]

@ritiek

Could you create a new enum enum InitializationRequiringAction and use it instead of passing strings for desired_action and matching on them? For one thing, this will avoid weird problems if we update the error messages.

r=me modulo that

[kennytm]

Please also leave no merge commits (those Merge branch 'master' into verbs). Rebase and squash after you're done.

[ritiek]

@arielb1 Sure, I'll report back as soon as I make progress.

@kennytm Okie, I'll keep that in mind.

[arielb1]

@bors r+ rollup

[bors]

📌 Commit 1be38e0 has been approved by arielb1