Auto merge of #88214 - notriddle:notriddle/for-loop-span-drop-temps-mut, r=nagisa

rustc: use more correct span data in for loop desugaring

Fixes #82462

Before:

      help: consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
         |
      LL |     for x in DroppingSlice(&*v).iter(); {
         |                                       +

After:

      help: consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
         |
      LL |     };
         |      +

This seems like a reasonable fix: since the desugared "expr_drop_temps_mut" contains the entire desugared loop construct, its span should contain the entire loop construct as well.

4 files changed, 9 insertions, 10 deletions

diff --git a/src/tools/clippy/clippy_lints/src/loops/for_kv_map.rs b/src/tools/clippy/clippy_lints/src/loops/for_kv_map.rs
index 68bef2f4c8b..12ffe7a1364 100644
--- a/src/tools/clippy/clippy_lints/src/loops/for_kv_map.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/for_kv_map.rs
@@ -15,7 +15,6 @@ pub(super) fn check<'tcx>(
     pat: &'tcx Pat<'_>,
     arg: &'tcx Expr<'_>,
     body: &'tcx Expr<'_>,
-    expr: &'tcx Expr<'_>,
 ) {
     let pat_span = pat.span;
 
@@ -43,7 +42,7 @@ pub(super) fn check<'tcx>(
                 span_lint_and_then(
                     cx,
                     FOR_KV_MAP,
-                    expr.span,
+                    arg_span,
                     &format!("you seem to want to iterate on a map's {}s", kind),
                     |diag| {
                         let map = sugg::Sugg::hir(cx, arg, "map");
diff --git a/src/tools/clippy/clippy_lints/src/loops/iter_next_loop.rs b/src/tools/clippy/clippy_lints/src/loops/iter_next_loop.rs
index 9148fbfd497..e640c62ebda 100644
--- a/src/tools/clippy/clippy_lints/src/loops/iter_next_loop.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/iter_next_loop.rs
@@ -5,12 +5,12 @@ use rustc_hir::Expr;
 use rustc_lint::LateContext;
 use rustc_span::sym;
 
-pub(super) fn check(cx: &LateContext<'_>, arg: &Expr<'_>, expr: &Expr<'_>) -> bool {
+pub(super) fn check(cx: &LateContext<'_>, arg: &Expr<'_>) -> bool {
     if is_trait_method(cx, arg, sym::Iterator) {
         span_lint(
             cx,
             ITER_NEXT_LOOP,
-            expr.span,
+            arg.span,
             "you are iterating over `Iterator::next()` which is an Option; this will compile but is \
             probably not what you want",
         );
diff --git a/src/tools/clippy/clippy_lints/src/loops/mod.rs b/src/tools/clippy/clippy_lints/src/loops/mod.rs
index 2860cb68f42..5df1b796401 100644
--- a/src/tools/clippy/clippy_lints/src/loops/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/mod.rs
@@ -616,15 +616,15 @@ fn check_for_loop<'tcx>(
         needless_range_loop::check(cx, pat, arg, body, expr);
         explicit_counter_loop::check(cx, pat, arg, body, expr);
     }
-    check_for_loop_arg(cx, pat, arg, expr);
-    for_kv_map::check(cx, pat, arg, body, expr);
+    check_for_loop_arg(cx, pat, arg);
+    for_kv_map::check(cx, pat, arg, body);
     mut_range_bound::check(cx, arg, body);
     single_element_loop::check(cx, pat, arg, body, expr);
     same_item_push::check(cx, pat, arg, body, expr);
     manual_flatten::check(cx, pat, arg, body, span);
 }
 
-fn check_for_loop_arg(cx: &LateContext<'_>, pat: &Pat<'_>, arg: &Expr<'_>, expr: &Expr<'_>) {
+fn check_for_loop_arg(cx: &LateContext<'_>, pat: &Pat<'_>, arg: &Expr<'_>) {
     let mut next_loop_linted = false; // whether or not ITER_NEXT_LOOP lint was used
 
     if let ExprKind::MethodCall(method, _, [self_arg], _) = arg.kind {
@@ -637,7 +637,7 @@ fn check_for_loop_arg(cx: &LateContext<'_>, pat: &Pat<'_>, arg: &Expr<'_>, expr:
                 explicit_into_iter_loop::check(cx, self_arg, arg);
             },
             "next" => {
-                next_loop_linted = iter_next_loop::check(cx, arg, expr);
+                next_loop_linted = iter_next_loop::check(cx, arg);
             },
             _ => {},
         }
diff --git a/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs b/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs
index e8f3550283a..7157b801185 100644
--- a/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs
@@ -144,7 +144,7 @@ pub(super) fn check<'tcx>(
                     span_lint_and_then(
                         cx,
                         NEEDLESS_RANGE_LOOP,
-                        expr.span,
+                        arg.span,
                         &format!("the loop variable `{}` is used to index `{}`", ident.name, indexed),
                         |diag| {
                             multispan_sugg(
@@ -170,7 +170,7 @@ pub(super) fn check<'tcx>(
                     span_lint_and_then(
                         cx,
                         NEEDLESS_RANGE_LOOP,
-                        expr.span,
+                        arg.span,
                         &format!("the loop variable `{}` is only used to index `{}`", ident.name, indexed),
                         |diag| {
                             multispan_sugg(