Allowed unused parameters before used ones #12139
Conversation
A running tally of unused parameters is kept durin checking unused locals. It's reset to `[]` whenever a used parameter is found. If any are left after done checking a scope they're logged as errors.
Added a third parameter existing tests that previously had an unused and a used parameter in that order.
|
Hi @JoshuaKGoldberg, I'm your friendly neighborhood Microsoft Pull Request Bot (You can call me MSBOT). Thanks for your contribution!
TTYL, MSBOT; |
| } | ||
|
|
||
| function checkUnusedParameterLocals(locals: Map<Symbol>): void { | ||
| let unusedParameterLocals: Symbol[] | undefined = []; |
There was a problem hiding this comment.
From a performance perspective I was hesitant to make a new [] no matter what. Hence the slight added complexity.
| } | ||
| } | ||
| } | ||
|
|
||
| if (unusedParameterLocals) { | ||
| forEach(unusedParameterLocals, local => error(local.valueDeclaration.name, Diagnostics._0_is_declared_but_never_used, local.name)); |
There was a problem hiding this comment.
Should unusedParameterLocals be sorted? Map guarantees iteration in insertion order, but does TS guarantee locals be in inserted order? Do we want to rely on that guarantee?
|
In my experience, it's useful to know when you aren't using a parameter, regardless of where that parameter appears. |
This PR addresses concerns listed in #9458 by removing errors logged for any unused parameters, particularly from @KnisterPeter and myself. Errors are now skipped for unused parameters that come before used parameters.
Asking for
_-prefixed variable names as the primary method of marking variables as unused can be non-optimal for several reasons: