Auto merge of rust-lang#10947 - Centri3:needless_lifetimes, r=llogiq

Improve suggestion for [`needless_lifetimes`]

Fixes rust-lang#10093

changelog: [`needless_lifetimes`]: Suggestion now points at the elidable lifetimes, rather than the entire function declaration

Author: bors

clippy_lints/src/lifetimes.rs

@@ -1,5 +1,6 @@
 use clippy_utils::diagnostics::{span_lint, span_lint_and_then};
 use clippy_utils::trait_ref_of_method;
+use itertools::Itertools;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::nested_filter::{self as hir_nested_filter, NestedFilter};
@@ -201,7 +202,19 @@ fn check_fn_inner<'tcx>(
         span_lint_and_then(
             cx,
             NEEDLESS_LIFETIMES,
-            span.with_hi(sig.decl.output.span().hi()),
+            elidable_lts
+                .iter()
+                .map(|&lt| cx.tcx.def_span(lt))
+                .chain(usages.iter().filter_map(|usage| {
+                    if let LifetimeName::Param(def_id) = usage.res
+                        && elidable_lts.contains(&def_id)
+                    {
+                        return Some(usage.ident.span);
+                    }
+
+                    None
+                }))
+                .collect_vec(),
             &format!("the following explicit lifetimes could be elided: {lts}"),
             |diag| {
                 if sig.header.is_async() {

tests/ui/crashes/ice-2774.stderr

@@ -1,8 +1,8 @@
 error: the following explicit lifetimes could be elided: 'a
-  --> $DIR/ice-2774.rs:15:1
+  --> $DIR/ice-2774.rs:15:28
    |
 LL | pub fn add_barfoos_to_foos<'a>(bars: &HashSet<&'a Bar>) {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                            ^^                  ^^
    |
    = note: `-D clippy::needless-lifetimes` implied by `-D warnings`
 help: elide the lifetimes

tests/ui/crashes/needless_lifetimes_impl_trait.stderr

@@ -1,8 +1,8 @@
 error: the following explicit lifetimes could be elided: 'a
-  --> $DIR/needless_lifetimes_impl_trait.rs:15:5
+  --> $DIR/needless_lifetimes_impl_trait.rs:15:12
    |
 LL |     fn baz<'a>(&'a self) -> impl Foo + 'a {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^   ^^                     ^^
    |
 note: the lint level is defined here
   --> $DIR/needless_lifetimes_impl_trait.rs:1:9

tests/ui/issue_4266.stderr

@@ -1,16 +1,16 @@
 error: the following explicit lifetimes could be elided: 'a
-  --> $DIR/issue_4266.rs:4:1
+  --> $DIR/issue_4266.rs:4:16
    |
 LL | async fn sink1<'a>(_: &'a str) {} // lint
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                ^^      ^^
    |
    = note: `-D clippy::needless-lifetimes` implied by `-D warnings`
 
 error: the following explicit lifetimes could be elided: 'a
-  --> $DIR/issue_4266.rs:8:1
+  --> $DIR/issue_4266.rs:8:21
    |
 LL | async fn one_to_one<'a>(s: &'a str) -> &'a str {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                     ^^      ^^
 
 error: methods called `new` usually take no `self`
   --> $DIR/issue_4266.rs:28:22