unwrap_used, expect_used: accept macro result as receiver
#14575
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|
Lintcheck shows many new hits, as expected (mostly with |
| pub fn method_call_expansion_ok<'tcx>( | ||
| recv: &'tcx Expr<'tcx>, | ||
| ) -> Option<(&'tcx str, &'tcx Expr<'tcx>, &'tcx [Expr<'tcx>], Span, Span)> { | ||
| if let ExprKind::MethodCall(path, receiver, args, call_span) = recv.kind { | ||
| let name = path.ident.name.as_str(); | ||
| return Some((name, receiver, args, path.ident.span, call_span)); | ||
| } | ||
| None | ||
| } |
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This doesn't really add anything over just matching inline.
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The idea was to make it easy for some lints use the pattern
if let Some((_, outer_receiver, _, _)) = method_call(expr) {
if let Some((_, inner_receiver, _)) = method_call_expansion_ok(outer_receiver) {
…
}
}since in some cases they wouldn't care if the inner_receiver was a macro call.
For example, we could easily (I just made the check) warn on
macro_rules! iter { ($e:expr) => { $e.iter() }; }
let _ = iter!([String::new()]).cloned().count();with
error: unneeded cloning of iterator items
--> /tmp/t.rs:6:13
|
6 | let _ = iter!([String::new()]).cloned().count();
| ^^^^^^^^^^^^^^^^^^^^^^---------^^^^^^^^
| |
| help: remove
Just by replacing a call to method_call() in methods/mod.rs with a call to method_call_expansion_ok(), and using the right span when printing the error message. There are really no good reasons not to lint when the receiver of .cloned() comes from expansion here, and this function would facilitate that.
changelog: [
unwrap_used,expect_used]: lint even when the receiver is a macro expansion resultThis also paves the way for expanding more method call lints to expanded receivers or arguments.
Fixes #13455