Code fix should prefer import type

[andrewbranch]

Noticed this while reviewing @johnnyreilly’s post about importsNotUsedAsValues, verbatimModuleSyntax, and eslint.

importsNotUsedAsValues would produce errors any time the whole import declaration wasn’t marked as type-only but could be, so the error span was over the whole import, and the only fix that would satisfy it was to use a top-level import type. verbatimModuleSyntax, on the other hand, cares more about whether the individual import specifiers are safe to emit, so the error span from that option is placed on individual import specifiers, and using a type modifier on each specifier can satisfy the check. However, under verbatimModuleSyntax, it’s generally preferable to use a top-level import type on the whole import declaration when possible, and the built-in codefix hadn’t been updated to consider that. Even though it’s no longer a TS error to have an import that will unnecessarily be emitted to JS, default behavior from auto-imports and codefixes should avoid that.

For individual fixes, both fix options are offered if import type is possible, with the import type being sorted first:

Using import type is not possible when other specifiers are already used as values:

For fix-all, import type is used whenever possible.

[andrewbranch]

I’m not sure if the two fix options should have different fixNames

[sheetalkamat]

Change looks good to me but i don't know about this either.

[andrewbranch]

Asked at the editor sync and this is only used for telemetry, and the telemetry stakeholders don’t care if they have the same name.

[jakebailey]

LGTM, though it seems like our Convert ... language is somewhat universal; is it worth preserving that wording?

[andrewbranch]

I think it’s usually better to quote exact syntax, and “type-only import” is ambiguous between type-only import declarations and type-only import specifiers. Not sure how to preserve the word “convert” and disambiguate, and I also don’t think I like the word to describe just adding a modifier.

[andrewbranch]

I’m going to add a fix-all test before merging.