Auto merge of #104688 - flip1995:clippyup, r=Manishearth,flip1995

Update Clippy

r? `@Manishearth`

Sorry for taking so long. There were so many blockers and so little time. This situation should be mitigated with #104007 in the future.

26 files changed, 811 insertions, 169 deletions

diff --git a/clippy_lints/src/methods/chars_cmp_with_unwrap.rs b/clippy_lints/src/methods/chars_cmp_with_unwrap.rs
index 7e808760663..27a05337a29 100644
--- a/clippy_lints/src/methods/chars_cmp_with_unwrap.rs
+++ b/clippy_lints/src/methods/chars_cmp_with_unwrap.rs
@@ -9,8 +9,8 @@ use rustc_lint::LateContext;
 use rustc_lint::Lint;
 
 /// Wrapper fn for `CHARS_NEXT_CMP` and `CHARS_LAST_CMP` lints with `unwrap()`.
-pub(super) fn check<'tcx>(
-    cx: &LateContext<'tcx>,
+pub(super) fn check(
+    cx: &LateContext<'_>,
     info: &crate::methods::BinaryExprInfo<'_>,
     chain_methods: &[&str],
     lint: &'static Lint,
diff --git a/clippy_lints/src/methods/chars_last_cmp.rs b/clippy_lints/src/methods/chars_last_cmp.rs
index 07bbc5ca1bf..2efff4c3c54 100644
--- a/clippy_lints/src/methods/chars_last_cmp.rs
+++ b/clippy_lints/src/methods/chars_last_cmp.rs
@@ -4,7 +4,7 @@ use rustc_lint::LateContext;
 use super::CHARS_LAST_CMP;
 
 /// Checks for the `CHARS_LAST_CMP` lint.
-pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, info: &crate::methods::BinaryExprInfo<'_>) -> bool {
+pub(super) fn check(cx: &LateContext<'_>, info: &crate::methods::BinaryExprInfo<'_>) -> bool {
     if chars_cmp::check(cx, info, &["chars", "last"], CHARS_LAST_CMP, "ends_with") {
         true
     } else {
diff --git a/clippy_lints/src/methods/chars_last_cmp_with_unwrap.rs b/clippy_lints/src/methods/chars_last_cmp_with_unwrap.rs
index c29ee0ec8c8..5b8713f7d79 100644
--- a/clippy_lints/src/methods/chars_last_cmp_with_unwrap.rs
+++ b/clippy_lints/src/methods/chars_last_cmp_with_unwrap.rs
@@ -4,7 +4,7 @@ use rustc_lint::LateContext;
 use super::CHARS_LAST_CMP;
 
 /// Checks for the `CHARS_LAST_CMP` lint with `unwrap()`.
-pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, info: &crate::methods::BinaryExprInfo<'_>) -> bool {
+pub(super) fn check(cx: &LateContext<'_>, info: &crate::methods::BinaryExprInfo<'_>) -> bool {
     if chars_cmp_with_unwrap::check(cx, info, &["chars", "last", "unwrap"], CHARS_LAST_CMP, "ends_with") {
         true
     } else {
diff --git a/clippy_lints/src/methods/chars_next_cmp.rs b/clippy_lints/src/methods/chars_next_cmp.rs
index a6701d8830e..b631fecab97 100644
--- a/clippy_lints/src/methods/chars_next_cmp.rs
+++ b/clippy_lints/src/methods/chars_next_cmp.rs
@@ -3,6 +3,6 @@ use rustc_lint::LateContext;
 use super::CHARS_NEXT_CMP;
 
 /// Checks for the `CHARS_NEXT_CMP` lint.
-pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, info: &crate::methods::BinaryExprInfo<'_>) -> bool {
+pub(super) fn check(cx: &LateContext<'_>, info: &crate::methods::BinaryExprInfo<'_>) -> bool {
     crate::methods::chars_cmp::check(cx, info, &["chars", "next"], CHARS_NEXT_CMP, "starts_with")
 }
diff --git a/clippy_lints/src/methods/chars_next_cmp_with_unwrap.rs b/clippy_lints/src/methods/chars_next_cmp_with_unwrap.rs
index 28ede28e935..caf21d3ff3b 100644
--- a/clippy_lints/src/methods/chars_next_cmp_with_unwrap.rs
+++ b/clippy_lints/src/methods/chars_next_cmp_with_unwrap.rs
@@ -3,6 +3,6 @@ use rustc_lint::LateContext;
 use super::CHARS_NEXT_CMP;
 
 /// Checks for the `CHARS_NEXT_CMP` lint with `unwrap()`.
-pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, info: &crate::methods::BinaryExprInfo<'_>) -> bool {
+pub(super) fn check(cx: &LateContext<'_>, info: &crate::methods::BinaryExprInfo<'_>) -> bool {
     crate::methods::chars_cmp_with_unwrap::check(cx, info, &["chars", "next", "unwrap"], CHARS_NEXT_CMP, "starts_with")
 }
diff --git a/clippy_lints/src/methods/collapsible_str_replace.rs b/clippy_lints/src/methods/collapsible_str_replace.rs
index 501646863fe..ac61b437788 100644
--- a/clippy_lints/src/methods/collapsible_str_replace.rs
+++ b/clippy_lints/src/methods/collapsible_str_replace.rs
@@ -23,7 +23,7 @@ pub(super) fn check<'tcx>(
         // If the parent node's `to` argument is the same as the `to` argument
         // of the last replace call in the current chain, don't lint as it was already linted
         if let Some(parent) = get_parent_expr(cx, expr)
-            && let Some(("replace", _, [current_from, current_to], _)) = method_call(parent)
+            && let Some(("replace", _, [current_from, current_to], _, _)) = method_call(parent)
             && eq_expr_value(cx, to, current_to)
             && from_kind == cx.typeck_results().expr_ty(current_from).peel_refs().kind()
         {
@@ -48,7 +48,7 @@ fn collect_replace_calls<'tcx>(
     let mut from_args = VecDeque::new();
 
     let _: Option<()> = for_each_expr(expr, |e| {
-        if let Some(("replace", _, [from, to], _)) = method_call(e) {
+        if let Some(("replace", _, [from, to], _, _)) = method_call(e) {
             if eq_expr_value(cx, to_arg, to) && cx.typeck_results().expr_ty(from).peel_refs().is_char() {
                 methods.push_front(e);
                 from_args.push_front(from);
@@ -78,7 +78,7 @@ fn check_consecutive_replace_calls<'tcx>(
         .collect();
     let app = Applicability::MachineApplicable;
     let earliest_replace_call = replace_methods.methods.front().unwrap();
-    if let Some((_, _, [..], span_lo)) = method_call(earliest_replace_call) {
+    if let Some((_, _, [..], span_lo, _)) = method_call(earliest_replace_call) {
         span_lint_and_sugg(
             cx,
             COLLAPSIBLE_STR_REPLACE,
diff --git a/clippy_lints/src/methods/expect_used.rs b/clippy_lints/src/methods/expect_used.rs
index d59fefa1ddc..cce8f797e98 100644
--- a/clippy_lints/src/methods/expect_used.rs
+++ b/clippy_lints/src/methods/expect_used.rs
@@ -1,5 +1,5 @@
 use clippy_utils::diagnostics::span_lint_and_help;
-use clippy_utils::is_in_test_function;
+use clippy_utils::is_in_cfg_test;
 use clippy_utils::ty::is_type_diagnostic_item;
 use rustc_hir as hir;
 use rustc_lint::LateContext;
@@ -18,16 +18,16 @@ pub(super) fn check(
     let obj_ty = cx.typeck_results().expr_ty(recv).peel_refs();
 
     let mess = if is_type_diagnostic_item(cx, obj_ty, sym::Option) && !is_err {
-        Some((EXPECT_USED, "an Option", "None", ""))
+        Some((EXPECT_USED, "an `Option`", "None", ""))
     } else if is_type_diagnostic_item(cx, obj_ty, sym::Result) {
-        Some((EXPECT_USED, "a Result", if is_err { "Ok" } else { "Err" }, "an "))
+        Some((EXPECT_USED, "a `Result`", if is_err { "Ok" } else { "Err" }, "an "))
     } else {
         None
     };
 
     let method = if is_err { "expect_err" } else { "expect" };
 
-    if allow_expect_in_tests && is_in_test_function(cx.tcx, expr.hir_id) {
+    if allow_expect_in_tests && is_in_cfg_test(cx.tcx, expr.hir_id) {
         return;
     }
 
@@ -36,7 +36,7 @@ pub(super) fn check(
             cx,
             lint,
             expr.span,
-            &format!("used `{method}()` on `{kind}` value"),
+            &format!("used `{method}()` on {kind} value"),
             None,
             &format!("if this value is {none_prefix}`{none_value}`, it will panic"),
         );
diff --git a/clippy_lints/src/methods/filter_map.rs b/clippy_lints/src/methods/filter_map.rs
index 9719b2f1c51..f888c58a72d 100644
--- a/clippy_lints/src/methods/filter_map.rs
+++ b/clippy_lints/src/methods/filter_map.rs
@@ -17,7 +17,7 @@ use super::MANUAL_FILTER_MAP;
 use super::MANUAL_FIND_MAP;
 use super::OPTION_FILTER_MAP;
 
-fn is_method<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, method_name: Symbol) -> bool {
+fn is_method(cx: &LateContext<'_>, expr: &hir::Expr<'_>, method_name: Symbol) -> bool {
     match &expr.kind {
         hir::ExprKind::Path(QPath::TypeRelative(_, mname)) => mname.ident.name == method_name,
         hir::ExprKind::Path(QPath::Resolved(_, segments)) => {
@@ -46,7 +46,7 @@ fn is_method<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, method_name: Sy
     }
 }
 
-fn is_option_filter_map<'tcx>(cx: &LateContext<'tcx>, filter_arg: &hir::Expr<'_>, map_arg: &hir::Expr<'_>) -> bool {
+fn is_option_filter_map(cx: &LateContext<'_>, filter_arg: &hir::Expr<'_>, map_arg: &hir::Expr<'_>) -> bool {
     is_method(cx, map_arg, sym::unwrap) && is_method(cx, filter_arg, sym!(is_some))
 }
 
@@ -66,8 +66,8 @@ fn is_filter_some_map_unwrap(
 
 /// lint use of `filter().map()` or `find().map()` for `Iterators`
 #[allow(clippy::too_many_arguments)]
-pub(super) fn check<'tcx>(
-    cx: &LateContext<'tcx>,
+pub(super) fn check(
+    cx: &LateContext<'_>,
     expr: &hir::Expr<'_>,
     filter_recv: &hir::Expr<'_>,
     filter_arg: &hir::Expr<'_>,
diff --git a/clippy_lints/src/methods/inefficient_to_string.rs b/clippy_lints/src/methods/inefficient_to_string.rs
index 4f4f543e8a9..d8c821bc9ee 100644
--- a/clippy_lints/src/methods/inefficient_to_string.rs
+++ b/clippy_lints/src/methods/inefficient_to_string.rs
@@ -12,8 +12,8 @@ use rustc_span::symbol::{Symbol, sym};
 use super::INEFFICIENT_TO_STRING;
 
 /// Checks for the `INEFFICIENT_TO_STRING` lint
-pub fn check<'tcx>(
-    cx: &LateContext<'tcx>,
+pub fn check(
+    cx: &LateContext<'_>,
     expr: &hir::Expr<'_>,
     method_name: Symbol,
     receiver: &hir::Expr<'_>,
diff --git a/clippy_lints/src/methods/iter_nth_zero.rs b/clippy_lints/src/methods/iter_nth_zero.rs
index 68d906c3ea3..c830958d5c8 100644
--- a/clippy_lints/src/methods/iter_nth_zero.rs
+++ b/clippy_lints/src/methods/iter_nth_zero.rs
@@ -10,7 +10,7 @@ use rustc_span::sym;
 
 use super::ITER_NTH_ZERO;
 
-pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>, arg: &hir::Expr<'_>) {
+pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>, arg: &hir::Expr<'_>) {
     if_chain! {
         if is_trait_method(cx, expr, sym::Iterator);
         if let Some((Constant::Int(0), _)) = constant(cx, cx.typeck_results(), arg);
diff --git a/clippy_lints/src/methods/iter_on_single_or_empty_collections.rs b/clippy_lints/src/methods/iter_on_single_or_empty_collections.rs
index 4f73b3ec422..70abe4891d9 100644
--- a/clippy_lints/src/methods/iter_on_single_or_empty_collections.rs
+++ b/clippy_lints/src/methods/iter_on_single_or_empty_collections.rs
@@ -25,7 +25,7 @@ impl IterType {
     }
 }
 
-pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>, method_name: &str, recv: &Expr<'_>) {
+pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, method_name: &str, recv: &Expr<'_>) {
     let item = match recv.kind {
         ExprKind::Array([]) => None,
         ExprKind::Array([e]) => Some(e),
diff --git a/clippy_lints/src/methods/manual_saturating_arithmetic.rs b/clippy_lints/src/methods/manual_saturating_arithmetic.rs
index b80541b8647..a7284c64497 100644
--- a/clippy_lints/src/methods/manual_saturating_arithmetic.rs
+++ b/clippy_lints/src/methods/manual_saturating_arithmetic.rs
@@ -67,7 +67,7 @@ enum MinMax {
     Max,
 }
 
-fn is_min_or_max<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>) -> Option<MinMax> {
+fn is_min_or_max(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> Option<MinMax> {
     // `T::max_value()` `T::min_value()` inherent methods
     if_chain! {
         if let hir::ExprKind::Call(func, args) = &expr.kind;
diff --git a/clippy_lints/src/methods/manual_str_repeat.rs b/clippy_lints/src/methods/manual_str_repeat.rs
index 13c47c03a80..a08f7254053 100644
--- a/clippy_lints/src/methods/manual_str_repeat.rs
+++ b/clippy_lints/src/methods/manual_str_repeat.rs
@@ -59,10 +59,8 @@ pub(super) fn check(
         if let ExprKind::Call(repeat_fn, [repeat_arg]) = take_self_arg.kind;
         if is_path_diagnostic_item(cx, repeat_fn, sym::iter_repeat);
         if is_type_lang_item(cx, cx.typeck_results().expr_ty(collect_expr), LangItem::String);
-        if let Some(collect_id) = cx.typeck_results().type_dependent_def_id(collect_expr.hir_id);
         if let Some(take_id) = cx.typeck_results().type_dependent_def_id(take_expr.hir_id);
         if let Some(iter_trait_id) = cx.tcx.get_diagnostic_item(sym::Iterator);
-        if cx.tcx.trait_of_item(collect_id) == Some(iter_trait_id);
         if cx.tcx.trait_of_item(take_id) == Some(iter_trait_id);
         if let Some(repeat_kind) = parse_repeat_arg(cx, repeat_arg);
         let ctxt = collect_expr.span.ctxt();
diff --git a/clippy_lints/src/methods/map_clone.rs b/clippy_lints/src/methods/map_clone.rs
index 7ce14ec080b..6bc783c6d50 100644
--- a/clippy_lints/src/methods/map_clone.rs
+++ b/clippy_lints/src/methods/map_clone.rs
@@ -15,11 +15,11 @@ use rustc_span::{sym, Span};
 
 use super::MAP_CLONE;
 
-pub(super) fn check<'tcx>(
+pub(super) fn check(
     cx: &LateContext<'_>,
     e: &hir::Expr<'_>,
     recv: &hir::Expr<'_>,
-    arg: &'tcx hir::Expr<'_>,
+    arg: &hir::Expr<'_>,
     msrv: Option<RustcVersion>,
 ) {
     if_chain! {
diff --git a/clippy_lints/src/methods/map_collect_result_unit.rs b/clippy_lints/src/methods/map_collect_result_unit.rs
index d420f144eea..a0300d27870 100644
--- a/clippy_lints/src/methods/map_collect_result_unit.rs
+++ b/clippy_lints/src/methods/map_collect_result_unit.rs
@@ -1,5 +1,4 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::is_trait_method;
 use clippy_utils::source::snippet;
 use clippy_utils::ty::is_type_diagnostic_item;
 use if_chain::if_chain;
@@ -11,18 +10,10 @@ use rustc_span::symbol::sym;
 
 use super::MAP_COLLECT_RESULT_UNIT;
 
-pub(super) fn check(
-    cx: &LateContext<'_>,
-    expr: &hir::Expr<'_>,
-    iter: &hir::Expr<'_>,
-    map_fn: &hir::Expr<'_>,
-    collect_recv: &hir::Expr<'_>,
-) {
+pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, iter: &hir::Expr<'_>, map_fn: &hir::Expr<'_>) {
+    // return of collect `Result<(),_>`
+    let collect_ret_ty = cx.typeck_results().expr_ty(expr);
     if_chain! {
-        // called on Iterator
-        if is_trait_method(cx, collect_recv, sym::Iterator);
-        // return of collect `Result<(),_>`
-        let collect_ret_ty = cx.typeck_results().expr_ty(expr);
         if is_type_diagnostic_item(cx, collect_ret_ty, sym::Result);
         if let ty::Adt(_, substs) = collect_ret_ty.kind();
         if let Some(result_t) = substs.types().next();
diff --git a/clippy_lints/src/methods/map_err_ignore.rs b/clippy_lints/src/methods/map_err_ignore.rs
index 1fb6617145e..b773b3e423f 100644
--- a/clippy_lints/src/methods/map_err_ignore.rs
+++ b/clippy_lints/src/methods/map_err_ignore.rs
@@ -6,7 +6,7 @@ use rustc_span::sym;
 
 use super::MAP_ERR_IGNORE;
 
-pub(super) fn check<'tcx>(cx: &LateContext<'_>, e: &Expr<'_>, arg: &'tcx Expr<'_>) {
+pub(super) fn check(cx: &LateContext<'_>, e: &Expr<'_>, arg: &Expr<'_>) {
     if let Some(method_id) = cx.typeck_results().type_dependent_def_id(e.hir_id)
         && let Some(impl_id) = cx.tcx.impl_of_method(method_id)
         && is_type_diagnostic_item(cx, cx.tcx.type_of(impl_id), sym::Result)
diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs
index 8a76ba0b064..38165ab4fb2 100644
--- a/clippy_lints/src/methods/mod.rs
+++ b/clippy_lints/src/methods/mod.rs
@@ -54,6 +54,7 @@ mod map_flatten;
 mod map_identity;
 mod map_unwrap_or;
 mod mut_mutex_lock;
+mod needless_collect;
 mod needless_option_as_deref;
 mod needless_option_take;
 mod no_effect_replace;
@@ -69,6 +70,8 @@ mod path_buf_push_overwrite;
 mod range_zip_with_len;
 mod repeat_once;
 mod search_is_some;
+mod seek_from_current;
+mod seek_to_start_instead_of_rewind;
 mod single_char_add_str;
 mod single_char_insert_string;
 mod single_char_pattern;
@@ -101,12 +104,11 @@ mod zst_offset;
 use bind_instead_of_map::BindInsteadOfMap;
 use clippy_utils::consts::{constant, Constant};
 use clippy_utils::diagnostics::{span_lint, span_lint_and_help};
-use clippy_utils::ty::{contains_adt_constructor, implements_trait, is_copy, is_type_diagnostic_item};
-use clippy_utils::{contains_return, is_trait_method, iter_input_pats, meets_msrv, msrvs, return_ty};
+use clippy_utils::ty::{contains_ty_adt_constructor_opaque, implements_trait, is_copy, is_type_diagnostic_item};
+use clippy_utils::{contains_return, is_bool, is_trait_method, iter_input_pats, meets_msrv, msrvs, return_ty};
 use if_chain::if_chain;
 use rustc_hir as hir;
-use rustc_hir::def::Res;
-use rustc_hir::{Expr, ExprKind, PrimTy, QPath, TraitItem, TraitItemKind};
+use rustc_hir::{Expr, ExprKind, TraitItem, TraitItemKind};
 use rustc_hir_analysis::hir_ty_to_ty;
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
@@ -156,9 +158,9 @@ declare_clippy_lint! {
     /// ```
     /// Use instead:
     /// ```rust
-    /// let hello = "hesuo worpd".replace(&['s', 'u', 'p'], "l");
+    /// let hello = "hesuo worpd".replace(['s', 'u', 'p'], "l");
     /// ```
-    #[clippy::version = "1.64.0"]
+    #[clippy::version = "1.65.0"]
     pub COLLAPSIBLE_STR_REPLACE,
     perf,
     "collapse consecutive calls to str::replace (2 or more) into a single call"
@@ -829,32 +831,30 @@ declare_clippy_lint! {
     /// etc. instead.
     ///
     /// ### Why is this bad?
-    /// The function will always be called and potentially
-    /// allocate an object acting as the default.
+    /// The function will always be called. This is only bad if it allocates or
+    /// does some non-trivial amount of work.
     ///
     /// ### Known problems
-    /// If the function has side-effects, not calling it will
-    /// change the semantic of the program, but you shouldn't rely on that anyway.
+    /// If the function has side-effects, not calling it will change the
+    /// semantic of the program, but you shouldn't rely on that.
+    ///
+    /// The lint also cannot figure out whether the function you call is
+    /// actually expensive to call or not.
     ///
     /// ### Example
     /// ```rust
     /// # let foo = Some(String::new());
-    /// foo.unwrap_or(String::new());
+    /// foo.unwrap_or(String::from("empty"));
     /// ```
     ///
     /// Use instead:
     /// ```rust
     /// # let foo = Some(String::new());
-    /// foo.unwrap_or_else(String::new);
-    ///
-    /// // or
-    ///
-    /// # let foo = Some(String::new());
-    /// foo.unwrap_or_default();
+    /// foo.unwrap_or_else(|| String::from("empty"));
     /// ```
     #[clippy::version = "pre 1.29.0"]
     pub OR_FUN_CALL,
-    perf,
+    nursery,
     "using any `*or` method with a function call, which suggests `*or_else`"
 }
 
@@ -1728,7 +1728,7 @@ declare_clippy_lint! {
 
 declare_clippy_lint! {
     /// ### What it does
-    /// Checks for usage of `_.as_ref().map(Deref::deref)` or it's aliases (such as String::as_str).
+    /// Checks for usage of `_.as_ref().map(Deref::deref)` or its aliases (such as String::as_str).
     ///
     /// ### Why is this bad?
     /// Readability, this can be written more concisely as
@@ -2094,8 +2094,7 @@ declare_clippy_lint! {
     /// let s = "Hello world!";
     /// let cow = Cow::Borrowed(s);
     ///
-    /// let data = cow.into_owned();
-    /// assert!(matches!(data, String))
+    /// let _data: String = cow.into_owned();
     /// ```
     #[clippy::version = "1.65.0"]
     pub SUSPICIOUS_TO_OWNED,
@@ -2426,7 +2425,7 @@ declare_clippy_lint! {
     /// ### Known problems
     ///
     /// The type of the resulting iterator might become incompatible with its usage
-    #[clippy::version = "1.64.0"]
+    #[clippy::version = "1.65.0"]
     pub ITER_ON_SINGLE_ITEMS,
     nursery,
     "Iterator for array of length 1"
@@ -2458,7 +2457,7 @@ declare_clippy_lint! {
     /// ### Known problems
     ///
     /// The type of the resulting iterator might become incompatible with its usage
-    #[clippy::version = "1.64.0"]
+    #[clippy::version = "1.65.0"]
     pub ITER_ON_EMPTY_COLLECTIONS,
     nursery,
     "Iterator for empty array"
@@ -3066,6 +3065,102 @@ declare_clippy_lint! {
     "iterating on map using `iter` when `keys` or `values` would do"
 }
 
+declare_clippy_lint! {
+    /// ### What it does
+    ///
+    /// Checks an argument of `seek` method of `Seek` trait
+    /// and if it start seek from `SeekFrom::Current(0)`, suggests `stream_position` instead.
+    ///
+    /// ### Why is this bad?
+    ///
+    /// Readability. Use dedicated method.
+    ///
+    /// ### Example
+    ///
+    /// ```rust,no_run
+    /// use std::fs::File;
+    /// use std::io::{self, Write, Seek, SeekFrom};
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let mut f = File::create("foo.txt")?;
+    ///     f.write_all(b"Hello")?;
+    ///     eprintln!("Written {} bytes", f.seek(SeekFrom::Current(0))?);
+    ///
+    ///     Ok(())
+    /// }
+    /// ```
+    /// Use instead:
+    /// ```rust,no_run
+    /// use std::fs::File;
+    /// use std::io::{self, Write, Seek, SeekFrom};
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let mut f = File::create("foo.txt")?;
+    ///     f.write_all(b"Hello")?;
+    ///     eprintln!("Written {} bytes", f.stream_position()?);
+    ///
+    ///     Ok(())
+    /// }
+    /// ```
+    #[clippy::version = "1.66.0"]
+    pub SEEK_FROM_CURRENT,
+    complexity,
+    "use dedicated method for seek from current position"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    ///
+    /// Checks for jumps to the start of a stream that implements `Seek`
+    /// and uses the `seek` method providing `Start` as parameter.
+    ///
+    /// ### Why is this bad?
+    ///
+    /// Readability. There is a specific method that was implemented for
+    /// this exact scenario.
+    ///
+    /// ### Example
+    /// ```rust
+    /// # use std::io;
+    /// fn foo<T: io::Seek>(t: &mut T) {
+    ///     t.seek(io::SeekFrom::Start(0));
+    /// }
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// # use std::io;
+    /// fn foo<T: io::Seek>(t: &mut T) {
+    ///     t.rewind();
+    /// }
+    /// ```
+    #[clippy::version = "1.66.0"]
+    pub SEEK_TO_START_INSTEAD_OF_REWIND,
+    complexity,
+    "jumping to the start of stream using `seek` method"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for functions collecting an iterator when collect
+    /// is not needed.
+    ///
+    /// ### Why is this bad?
+    /// `collect` causes the allocation of a new data structure,
+    /// when this allocation may not be needed.
+    ///
+    /// ### Example
+    /// ```rust
+    /// # let iterator = vec![1].into_iter();
+    /// let len = iterator.clone().collect::<Vec<_>>().len();
+    /// // should be
+    /// let len = iterator.count();
+    /// ```
+    #[clippy::version = "1.30.0"]
+    pub NEEDLESS_COLLECT,
+    nursery,
+    "collecting an iterator when collect is not needed"
+}
+
 pub struct Methods {
     avoid_breaking_exported_api: bool,
     msrv: Option<RustcVersion>,
@@ -3190,16 +3285,19 @@ impl_lint_pass!(Methods => [
     VEC_RESIZE_TO_ZERO,
     VERBOSE_FILE_READS,
     ITER_KV_MAP,
+    SEEK_FROM_CURRENT,
+    SEEK_TO_START_INSTEAD_OF_REWIND,
+    NEEDLESS_COLLECT,
 ]);
 
 /// Extracts a method call name, args, and `Span` of the method name.
 fn method_call<'tcx>(
     recv: &'tcx hir::Expr<'tcx>,
-) -> Option<(&'tcx str, &'tcx hir::Expr<'tcx>, &'tcx [hir::Expr<'tcx>], Span)> {
-    if let ExprKind::MethodCall(path, receiver, args, _) = recv.kind {
+) -> Option<(&'tcx str, &'tcx hir::Expr<'tcx>, &'tcx [hir::Expr<'tcx>], Span, Span)> {
+    if let ExprKind::MethodCall(path, receiver, args, call_span) = recv.kind {
         if !args.iter().any(|e| e.span.from_expansion()) && !receiver.span.from_expansion() {
             let name = path.ident.name.as_str();
-            return Some((name, receiver, args, path.ident.span));
+            return Some((name, receiver, args, path.ident.span, call_span));
         }
     }
     None
@@ -3316,36 +3414,10 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
         if let hir::ImplItemKind::Fn(_, _) = impl_item.kind {
             let ret_ty = return_ty(cx, impl_item.hir_id());
 
-            // walk the return type and check for Self (this does not check associated types)
-            if let Some(self_adt) = self_ty.ty_adt_def() {
-                if contains_adt_constructor(ret_ty, self_adt) {
-                    return;
-                }
-            } else if ret_ty.contains(self_ty) {
+            if contains_ty_adt_constructor_opaque(cx, ret_ty, self_ty) {
                 return;
             }
 
-            // if return type is impl trait, check the associated types
-            if let ty::Opaque(def_id, _) = *ret_ty.kind() {
-                // one of the associated types must be Self
-                for &(predicate, _span) in cx.tcx.explicit_item_bounds(def_id) {
-                    if let ty::PredicateKind::Projection(projection_predicate) = predicate.kind().skip_binder() {
-                        let assoc_ty = match projection_predicate.term.unpack() {
-                            ty::TermKind::Ty(ty) => ty,
-                            ty::TermKind::Const(_c) => continue,
-                        };
-                        // walk the associated type and check for Self
-                        if let Some(self_adt) = self_ty.ty_adt_def() {
-                            if contains_adt_constructor(assoc_ty, self_adt) {
-                                return;
-                            }
-                        } else if assoc_ty.contains(self_ty) {
-                            return;
-                        }
-                    }
-                }
-            }
-
             if name == "new" && ret_ty != self_ty {
                 span_lint(
                     cx,
@@ -3411,7 +3483,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
 impl Methods {
     #[allow(clippy::too_many_lines)]
     fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        if let Some((name, recv, args, span)) = method_call(expr) {
+        if let Some((name, recv, args, span, call_span)) = method_call(expr) {
             match (name, args) {
                 ("add" | "offset" | "sub" | "wrapping_offset" | "wrapping_add" | "wrapping_sub", [_arg]) => {
                     zst_offset::check(cx, expr, recv);
@@ -3430,28 +3502,31 @@ impl Methods {
                 ("as_ref", []) => useless_asref::check(cx, expr, "as_ref", recv),
                 ("assume_init", []) => uninit_assumed_init::check(cx, expr, recv),
                 ("cloned", []) => cloned_instead_of_copied::check(cx, expr, recv, span, self.msrv),
-                ("collect", []) => match method_call(recv) {
-                    Some((name @ ("cloned" | "copied"), recv2, [], _)) => {
-                        iter_cloned_collect::check(cx, name, expr, recv2);
-                    },
-                    Some(("map", m_recv, [m_arg], _)) => {
-                        map_collect_result_unit::check(cx, expr, m_recv, m_arg, recv);
-                    },
-                    Some(("take", take_self_arg, [take_arg], _)) => {
-                        if meets_msrv(self.msrv, msrvs::STR_REPEAT) {
-                            manual_str_repeat::check(cx, expr, recv, take_self_arg, take_arg);
-                        }
-                    },
-                    _ => {},
+                ("collect", []) if is_trait_method(cx, expr, sym::Iterator) => {
+                    needless_collect::check(cx, span, expr, recv, call_span);
+                    match method_call(recv) {
+                        Some((name @ ("cloned" | "copied"), recv2, [], _, _)) => {
+                            iter_cloned_collect::check(cx, name, expr, recv2);
+                        },
+                        Some(("map", m_recv, [m_arg], _, _)) => {
+                            map_collect_result_unit::check(cx, expr, m_recv, m_arg);
+                        },
+                        Some(("take", take_self_arg, [take_arg], _, _)) => {
+                            if meets_msrv(self.msrv, msrvs::STR_REPEAT) {
+                                manual_str_repeat::check(cx, expr, recv, take_self_arg, take_arg);
+                            }
+                        },
+                        _ => {},
+                    }
                 },
                 ("count", []) if is_trait_method(cx, expr, sym::Iterator) => match method_call(recv) {
-                    Some(("cloned", recv2, [], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, true, false),
-                    Some((name2 @ ("into_iter" | "iter" | "iter_mut"), recv2, [], _)) => {
+                    Some(("cloned", recv2, [], _, _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, true, false),
+                    Some((name2 @ ("into_iter" | "iter" | "iter_mut"), recv2, [], _, _)) => {
                         iter_count::check(cx, expr, recv2, name2);
                     },
-                    Some(("map", _, [arg], _)) => suspicious_map::check(cx, expr, recv, arg),
-                    Some(("filter", recv2, [arg], _)) => bytecount::check(cx, expr, recv2, arg),
-                    Some(("bytes", recv2, [], _)) => bytes_count_to_len::check(cx, expr, recv, recv2),
+                    Some(("map", _, [arg], _, _)) => suspicious_map::check(cx, expr, recv, arg),
+                    Some(("filter", recv2, [arg], _, _)) => bytecount::check(cx, expr, recv2, arg),
+                    Some(("bytes", recv2, [], _, _)) => bytes_count_to_len::check(cx, expr, recv, recv2),
                     _ => {},
                 },
                 ("drain", [arg]) => {
@@ -3463,8 +3538,8 @@ impl Methods {
                     }
                 },
                 ("expect", [_]) => match method_call(recv) {
-                    Some(("ok", recv, [], _)) => ok_expect::check(cx, expr, recv),
-                    Some(("err", recv, [], err_span)) => err_expect::check(cx, expr, recv, self.msrv, span, err_span),
+                    Some(("ok", recv, [], _, _)) => ok_expect::check(cx, expr, recv),
+                    Some(("err", recv, [], err_span, _)) => err_expect::check(cx, expr, recv, self.msrv, span, err_span),
                     _ => expect_used::check(cx, expr, recv, false, self.allow_expect_in_tests),
                 },
                 ("expect_err", [_]) => expect_used::check(cx, expr, recv, true, self.allow_expect_in_tests),
@@ -3484,13 +3559,13 @@ impl Methods {
                     flat_map_option::check(cx, expr, arg, span);
                 },
                 ("flatten", []) => match method_call(recv) {
-                    Some(("map", recv, [map_arg], map_span)) => map_flatten::check(cx, expr, recv, map_arg, map_span),
-                    Some(("cloned", recv2, [], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, true),
+                    Some(("map", recv, [map_arg], map_span, _)) => map_flatten::check(cx, expr, recv, map_arg, map_span),
+                    Some(("cloned", recv2, [], _, _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, true),
                     _ => {},
                 },
                 ("fold", [init, acc]) => unnecessary_fold::check(cx, expr, init, acc, span),
                 ("for_each", [_]) => {
-                    if let Some(("inspect", _, [_], span2)) = method_call(recv) {
+                    if let Some(("inspect", _, [_], span2, _)) = method_call(recv) {
                         inspect_for_each::check(cx, expr, span2);
                     }
                 },
@@ -3510,12 +3585,12 @@ impl Methods {
                     iter_on_single_or_empty_collections::check(cx, expr, name, recv);
                 },
                 ("join", [join_arg]) => {
-                    if let Some(("collect", _, _, span)) = method_call(recv) {
+                    if let Some(("collect", _, _, span, _)) = method_call(recv) {
                         unnecessary_join::check(cx, expr, recv, join_arg, span);
                     }
                 },
                 ("last", []) | ("skip", [_]) => {
-                    if let Some((name2, recv2, args2, _span2)) = method_call(recv) {
+                    if let Some((name2, recv2, args2, _span2, _)) = method_call(recv) {
                         if let ("cloned", []) = (name2, args2) {
                             iter_overeager_cloned::check(cx, expr, recv, recv2, false, false);
                         }
@@ -3527,13 +3602,13 @@ impl Methods {
                 (name @ ("map" | "map_err"), [m_arg]) => {
                     if name == "map" {
                         map_clone::check(cx, expr, recv, m_arg, self.msrv);
-                        if let Some((map_name @ ("iter" | "into_iter"), recv2, _, _)) = method_call(recv) {
+                        if let Some((map_name @ ("iter" | "into_iter"), recv2, _, _, _)) = method_call(recv) {
                             iter_kv_map::check(cx, map_name, expr, recv2, m_arg);
                         }
                     } else {
                         map_err_ignore::check(cx, expr, m_arg);
                     }
-                    if let Some((name, recv2, args, span2)) = method_call(recv) {
+                    if let Some((name, recv2, args, span2,_)) = method_call(recv) {
                         match (name, args) {
                             ("as_mut", []) => option_as_ref_deref::check(cx, expr, recv2, m_arg, true, self.msrv),
                             ("as_ref", []) => option_as_ref_deref::check(cx, expr, recv2, m_arg, false, self.msrv),
@@ -3553,7 +3628,7 @@ impl Methods {
                     manual_ok_or::check(cx, expr, recv, def, map);
                 },
                 ("next", []) => {
-                    if let Some((name2, recv2, args2, _)) = method_call(recv) {
+                    if let Some((name2, recv2, args2, _, _)) = method_call(recv) {
                         match (name2, args2) {
                             ("cloned", []) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, false),
                             ("filter", [arg]) => filter_next::check(cx, expr, recv2, arg),
@@ -3566,10 +3641,10 @@ impl Methods {
                     }
                 },
                 ("nth", [n_arg]) => match method_call(recv) {
-                    Some(("bytes", recv2, [], _)) => bytes_nth::check(cx, expr, recv2, n_arg),
-                    Some(("cloned", recv2, [], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, false),
-                    Some(("iter", recv2, [], _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, false),
-                    Some(("iter_mut", recv2, [], _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, true),
+                    Some(("bytes", recv2, [], _, _)) => bytes_nth::check(cx, expr, recv2, n_arg),
+                    Some(("cloned", recv2, [], _, _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, false),
+                    Some(("iter", recv2, [], _, _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, false),
+                    Some(("iter_mut", recv2, [], _, _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, true),
                     _ => iter_nth_zero::check(cx, expr, recv, n_arg),
                 },
                 ("ok_or_else", [arg]) => unnecessary_lazy_eval::check(cx, expr, recv, arg, "ok_or"),
@@ -3604,6 +3679,14 @@ impl Methods {
                 ("resize", [count_arg, default_arg]) => {
                     vec_resize_to_zero::check(cx, expr, count_arg, default_arg, span);
                 },
+                ("seek", [arg]) => {
+                    if meets_msrv(self.msrv, msrvs::SEEK_FROM_CURRENT) {
+                        seek_from_current::check(cx, expr, recv, arg);
+                    }
+                    if meets_msrv(self.msrv, msrvs::SEEK_REWIND) {
+                        seek_to_start_instead_of_rewind::check(cx, expr, recv, arg, span);
+                    }
+                },
                 ("sort", []) => {
                     stable_sort_primitive::check(cx, expr, recv);
                 },
@@ -3626,7 +3709,7 @@ impl Methods {
                 },
                 ("step_by", [arg]) => iterator_step_by_zero::check(cx, expr, arg),
                 ("take", [_arg]) => {
-                    if let Some((name2, recv2, args2, _span2)) = method_call(recv) {
+                    if let Some((name2, recv2, args2, _span2, _)) = method_call(recv) {
                         if let ("cloned", []) = (name2, args2) {
                             iter_overeager_cloned::check(cx, expr, recv, recv2, false, false);
                         }
@@ -3649,13 +3732,13 @@ impl Methods {
                 },
                 ("unwrap", []) => {
                     match method_call(recv) {
-                        Some(("get", recv, [get_arg], _)) => {
+                        Some(("get", recv, [get_arg], _, _)) => {
                             get_unwrap::check(cx, expr, recv, get_arg, false);
                         },
-                        Some(("get_mut", recv, [get_arg], _)) => {
+                        Some(("get_mut", recv, [get_arg], _, _)) => {
                             get_unwrap::check(cx, expr, recv, get_arg, true);
                         },
-                        Some(("or", recv, [or_arg], or_span)) => {
+                        Some(("or", recv, [or_arg], or_span, _)) => {
                             or_then_unwrap::check(cx, expr, recv, or_arg, or_span);
                         },
                         _ => {},
@@ -3664,19 +3747,19 @@ impl Methods {
                 },
                 ("unwrap_err", []) => unwrap_used::check(cx, expr, recv, true, self.allow_unwrap_in_tests),
                 ("unwrap_or", [u_arg]) => match method_call(recv) {
-                    Some((arith @ ("checked_add" | "checked_sub" | "checked_mul"), lhs, [rhs], _)) => {
+                    Some((arith @ ("checked_add" | "checked_sub" | "checked_mul"), lhs, [rhs], _, _)) => {
                         manual_saturating_arithmetic::check(cx, expr, lhs, rhs, u_arg, &arith["checked_".len()..]);
                     },
-                    Some(("map", m_recv, [m_arg], span)) => {
+                    Some(("map", m_recv, [m_arg], span, _)) => {
                         option_map_unwrap_or::check(cx, expr, m_recv, m_arg, recv, u_arg, span);
                     },
-                    Some(("then_some", t_recv, [t_arg], _)) => {
+                    Some(("then_some", t_recv, [t_arg], _, _)) => {
                         obfuscated_if_else::check(cx, expr, t_recv, t_arg, u_arg);
                     },
                     _ => {},
                 },
                 ("unwrap_or_else", [u_arg]) => match method_call(recv) {
-                    Some(("map", recv, [map_arg], _))
+                    Some(("map", recv, [map_arg], _, _))
                         if map_unwrap_or::check(cx, expr, recv, map_arg, u_arg, self.msrv) => {},
                     _ => {
                         unwrap_or_else_default::check(cx, expr, recv, u_arg);
@@ -3697,7 +3780,7 @@ impl Methods {
 }
 
 fn check_is_some_is_none(cx: &LateContext<'_>, expr: &Expr<'_>, recv: &Expr<'_>, is_some: bool) {
-    if let Some((name @ ("find" | "position" | "rposition"), f_recv, [arg], span)) = method_call(recv) {
+    if let Some((name @ ("find" | "position" | "rposition"), f_recv, [arg], span, _)) = method_call(recv) {
         search_is_some::check(cx, expr, name, is_some, f_recv, arg, recv, span);
     }
 }
@@ -3906,14 +3989,6 @@ impl OutType {
     }
 }
 
-fn is_bool(ty: &hir::Ty<'_>) -> bool {
-    if let hir::TyKind::Path(QPath::Resolved(_, path)) = ty.kind {
-        matches!(path.res, Res::PrimTy(PrimTy::Bool))
-    } else {
-        false
-    }
-}
-
 fn fn_header_equals(expected: hir::FnHeader, actual: hir::FnHeader) -> bool {
     expected.constness == actual.constness
         && expected.unsafety == actual.unsafety
diff --git a/clippy_lints/src/methods/needless_collect.rs b/clippy_lints/src/methods/needless_collect.rs
new file mode 100644
index 00000000000..b088e642e0e
--- /dev/null
+++ b/clippy_lints/src/methods/needless_collect.rs
@@ -0,0 +1,456 @@
+use super::NEEDLESS_COLLECT;
+use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_hir_and_then};
+use clippy_utils::higher;
+use clippy_utils::source::{snippet, snippet_with_applicability};
+use clippy_utils::sugg::Sugg;
+use clippy_utils::ty::{is_type_diagnostic_item, make_normalized_projection, make_projection};
+use clippy_utils::{
+    can_move_expr_to_closure, get_enclosing_block, get_parent_node, is_trait_method, path_to_local, path_to_local_id,
+    CaptureKind,
+};
+use rustc_data_structures::fx::FxHashMap;
+use rustc_errors::{Applicability, MultiSpan};
+use rustc_hir::intravisit::{walk_block, walk_expr, Visitor};
+use rustc_hir::{
+    BindingAnnotation, Block, Expr, ExprKind, HirId, HirIdSet, Local, Mutability, Node, PatKind, Stmt, StmtKind,
+};
+use rustc_lint::LateContext;
+use rustc_middle::hir::nested_filter;
+use rustc_middle::ty::{self, AssocKind, EarlyBinder, GenericArg, GenericArgKind, Ty};
+use rustc_span::symbol::Ident;
+use rustc_span::{sym, Span, Symbol};
+
+const NEEDLESS_COLLECT_MSG: &str = "avoid using `collect()` when not needed";
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    name_span: Span,
+    collect_expr: &'tcx Expr<'_>,
+    iter_expr: &'tcx Expr<'tcx>,
+    call_span: Span,
+) {
+    if let Some(parent) = get_parent_node(cx.tcx, collect_expr.hir_id) {
+        match parent {
+            Node::Expr(parent) => {
+                if let ExprKind::MethodCall(name, _, args @ ([] | [_]), _) = parent.kind {
+                    let mut app = Applicability::MachineApplicable;
+                    let name = name.ident.as_str();
+                    let collect_ty = cx.typeck_results().expr_ty(collect_expr);
+
+                    let sugg: String = match name {
+                        "len" => {
+                            if let Some(adt) = collect_ty.ty_adt_def()
+                                && matches!(
+                                    cx.tcx.get_diagnostic_name(adt.did()),
+                                    Some(sym::Vec | sym::VecDeque | sym::LinkedList | sym::BinaryHeap)
+                                )
+                            {
+                                "count()".into()
+                            } else {
+                                return;
+                            }
+                        },
+                        "is_empty"
+                            if is_is_empty_sig(cx, parent.hir_id)
+                                && iterates_same_ty(cx, cx.typeck_results().expr_ty(iter_expr), collect_ty) =>
+                        {
+                            "next().is_none()".into()
+                        },
+                        "contains" => {
+                            if is_contains_sig(cx, parent.hir_id, iter_expr)
+                                && let Some(arg) = args.first()
+                            {
+                                let (span, prefix) = if let ExprKind::AddrOf(_, _, arg) = arg.kind {
+                                    (arg.span, "")
+                                } else {
+                                    (arg.span, "*")
+                                };
+                                let snip = snippet_with_applicability(cx, span, "??", &mut app);
+                                format!("any(|x| x == {prefix}{snip})")
+                            } else {
+                                return;
+                            }
+                        },
+                        _ => return,
+                    };
+
+                    span_lint_and_sugg(
+                        cx,
+                        NEEDLESS_COLLECT,
+                        call_span.with_hi(parent.span.hi()),
+                        NEEDLESS_COLLECT_MSG,
+                        "replace with",
+                        sugg,
+                        app,
+                    );
+                }
+            },
+            Node::Local(l) => {
+                if let PatKind::Binding(BindingAnnotation::NONE | BindingAnnotation::MUT, id, _, None)
+                    = l.pat.kind
+                    && let ty = cx.typeck_results().expr_ty(collect_expr)
+                    && [sym::Vec, sym::VecDeque, sym::BinaryHeap, sym::LinkedList].into_iter()
+                        .any(|item| is_type_diagnostic_item(cx, ty, item))
+                    && let iter_ty = cx.typeck_results().expr_ty(iter_expr)
+                    && let Some(block) = get_enclosing_block(cx, l.hir_id)
+                    && let Some(iter_calls) = detect_iter_and_into_iters(block, id, cx, get_captured_ids(cx, iter_ty))
+                    && let [iter_call] = &*iter_calls
+                {
+                    let mut used_count_visitor = UsedCountVisitor {
+                        cx,
+                        id,
+                        count: 0,
+                    };
+                    walk_block(&mut used_count_visitor, block);
+                    if used_count_visitor.count > 1 {
+                        return;
+                    }
+
+                    // Suggest replacing iter_call with iter_replacement, and removing stmt
+                    let mut span = MultiSpan::from_span(name_span);
+                    span.push_span_label(iter_call.span, "the iterator could be used here instead");
+                    span_lint_hir_and_then(
+                        cx,
+                        super::NEEDLESS_COLLECT,
+                        collect_expr.hir_id,
+                        span,
+                        NEEDLESS_COLLECT_MSG,
+                        |diag| {
+                            let iter_replacement = format!("{}{}", Sugg::hir(cx, iter_expr, ".."), iter_call.get_iter_method(cx));
+                            diag.multipart_suggestion(
+                                iter_call.get_suggestion_text(),
+                                vec![
+                                    (l.span, String::new()),
+                                    (iter_call.span, iter_replacement)
+                                ],
+                                Applicability::MaybeIncorrect,
+                            );
+                        },
+                    );
+                }
+            },
+            _ => (),
+        }
+    }
+}
+
+/// Checks if the given method call matches the expected signature of `([&[mut]] self) -> bool`
+fn is_is_empty_sig(cx: &LateContext<'_>, call_id: HirId) -> bool {
+    cx.typeck_results().type_dependent_def_id(call_id).map_or(false, |id| {
+        let sig = cx.tcx.fn_sig(id).skip_binder();
+        sig.inputs().len() == 1 && sig.output().is_bool()
+    })
+}
+
+/// Checks if `<iter_ty as Iterator>::Item` is the same as `<collect_ty as IntoIter>::Item`
+fn iterates_same_ty<'tcx>(cx: &LateContext<'tcx>, iter_ty: Ty<'tcx>, collect_ty: Ty<'tcx>) -> bool {
+    let item = Symbol::intern("Item");
+    if let Some(iter_trait) = cx.tcx.get_diagnostic_item(sym::Iterator)
+        && let Some(into_iter_trait) = cx.tcx.get_diagnostic_item(sym::IntoIterator)
+        && let Some(iter_item_ty) = make_normalized_projection(cx.tcx, cx.param_env, iter_trait, item, [iter_ty])
+        && let Some(into_iter_item_proj) = make_projection(cx.tcx, into_iter_trait, item, [collect_ty])
+        && let Ok(into_iter_item_ty) = cx.tcx.try_normalize_erasing_regions(
+            cx.param_env,
+            cx.tcx.mk_projection(into_iter_item_proj.item_def_id, into_iter_item_proj.substs)
+        )
+    {
+        iter_item_ty == into_iter_item_ty
+    } else {
+        false
+    }
+}
+
+/// Checks if the given method call matches the expected signature of
+/// `([&[mut]] self, &<iter_ty as Iterator>::Item) -> bool`
+fn is_contains_sig(cx: &LateContext<'_>, call_id: HirId, iter_expr: &Expr<'_>) -> bool {
+    let typeck = cx.typeck_results();
+    if let Some(id) = typeck.type_dependent_def_id(call_id)
+        && let sig = cx.tcx.fn_sig(id)
+        && sig.skip_binder().output().is_bool()
+        && let [_, search_ty] = *sig.skip_binder().inputs()
+        && let ty::Ref(_, search_ty, Mutability::Not) = *cx.tcx.erase_late_bound_regions(sig.rebind(search_ty)).kind()
+        && let Some(iter_trait) = cx.tcx.get_diagnostic_item(sym::Iterator)
+        && let Some(iter_item) = cx.tcx
+            .associated_items(iter_trait)
+            .find_by_name_and_kind(cx.tcx, Ident::with_dummy_span(Symbol::intern("Item")), AssocKind::Type, iter_trait)
+        && let substs = cx.tcx.mk_substs([GenericArg::from(typeck.expr_ty_adjusted(iter_expr))].into_iter())
+        && let proj_ty = cx.tcx.mk_projection(iter_item.def_id, substs)
+        && let Ok(item_ty) = cx.tcx.try_normalize_erasing_regions(cx.param_env, proj_ty)
+    {
+        item_ty == EarlyBinder(search_ty).subst(cx.tcx, cx.typeck_results().node_substs(call_id))
+    } else {
+        false
+    }
+}
+
+struct IterFunction {
+    func: IterFunctionKind,
+    span: Span,
+}
+impl IterFunction {
+    fn get_iter_method(&self, cx: &LateContext<'_>) -> String {
+        match &self.func {
+            IterFunctionKind::IntoIter => String::new(),
+            IterFunctionKind::Len => String::from(".count()"),
+            IterFunctionKind::IsEmpty => String::from(".next().is_none()"),
+            IterFunctionKind::Contains(span) => {
+                let s = snippet(cx, *span, "..");
+                if let Some(stripped) = s.strip_prefix('&') {
+                    format!(".any(|x| x == {stripped})")
+                } else {
+                    format!(".any(|x| x == *{s})")
+                }
+            },
+        }
+    }
+    fn get_suggestion_text(&self) -> &'static str {
+        match &self.func {
+            IterFunctionKind::IntoIter => {
+                "use the original Iterator instead of collecting it and then producing a new one"
+            },
+            IterFunctionKind::Len => {
+                "take the original Iterator's count instead of collecting it and finding the length"
+            },
+            IterFunctionKind::IsEmpty => {
+                "check if the original Iterator has anything instead of collecting it and seeing if it's empty"
+            },
+            IterFunctionKind::Contains(_) => {
+                "check if the original Iterator contains an element instead of collecting then checking"
+            },
+        }
+    }
+}
+enum IterFunctionKind {
+    IntoIter,
+    Len,
+    IsEmpty,
+    Contains(Span),
+}
+
+struct IterFunctionVisitor<'a, 'tcx> {
+    illegal_mutable_capture_ids: HirIdSet,
+    current_mutably_captured_ids: HirIdSet,
+    cx: &'a LateContext<'tcx>,
+    uses: Vec<Option<IterFunction>>,
+    hir_id_uses_map: FxHashMap<HirId, usize>,
+    current_statement_hir_id: Option<HirId>,
+    seen_other: bool,
+    target: HirId,
+}
+impl<'tcx> Visitor<'tcx> for IterFunctionVisitor<'_, 'tcx> {
+    fn visit_block(&mut self, block: &'tcx Block<'tcx>) {
+        for (expr, hir_id) in block.stmts.iter().filter_map(get_expr_and_hir_id_from_stmt) {
+            if check_loop_kind(expr).is_some() {
+                continue;
+            }
+            self.visit_block_expr(expr, hir_id);
+        }
+        if let Some(expr) = block.expr {
+            if let Some(loop_kind) = check_loop_kind(expr) {
+                if let LoopKind::Conditional(block_expr) = loop_kind {
+                    self.visit_block_expr(block_expr, None);
+                }
+            } else {
+                self.visit_block_expr(expr, None);
+            }
+        }
+    }
+
+    fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) {
+        // Check function calls on our collection
+        if let ExprKind::MethodCall(method_name, recv, [args @ ..], _) = &expr.kind {
+            if method_name.ident.name == sym!(collect) && is_trait_method(self.cx, expr, sym::Iterator) {
+                self.current_mutably_captured_ids = get_captured_ids(self.cx, self.cx.typeck_results().expr_ty(recv));
+                self.visit_expr(recv);
+                return;
+            }
+
+            if path_to_local_id(recv, self.target) {
+                if self
+                    .illegal_mutable_capture_ids
+                    .intersection(&self.current_mutably_captured_ids)
+                    .next()
+                    .is_none()
+                {
+                    if let Some(hir_id) = self.current_statement_hir_id {
+                        self.hir_id_uses_map.insert(hir_id, self.uses.len());
+                    }
+                    match method_name.ident.name.as_str() {
+                        "into_iter" => self.uses.push(Some(IterFunction {
+                            func: IterFunctionKind::IntoIter,
+                            span: expr.span,
+                        })),
+                        "len" => self.uses.push(Some(IterFunction {
+                            func: IterFunctionKind::Len,
+                            span: expr.span,
+                        })),
+                        "is_empty" => self.uses.push(Some(IterFunction {
+                            func: IterFunctionKind::IsEmpty,
+                            span: expr.span,
+                        })),
+                        "contains" => self.uses.push(Some(IterFunction {
+                            func: IterFunctionKind::Contains(args[0].span),
+                            span: expr.span,
+                        })),
+                        _ => {
+                            self.seen_other = true;
+                            if let Some(hir_id) = self.current_statement_hir_id {
+                                self.hir_id_uses_map.remove(&hir_id);
+                            }
+                        },
+                    }
+                }
+                return;
+            }
+
+            if let Some(hir_id) = path_to_local(recv) {
+                if let Some(index) = self.hir_id_uses_map.remove(&hir_id) {
+                    if self
+                        .illegal_mutable_capture_ids
+                        .intersection(&self.current_mutably_captured_ids)
+                        .next()
+                        .is_none()
+                    {
+                        if let Some(hir_id) = self.current_statement_hir_id {
+                            self.hir_id_uses_map.insert(hir_id, index);
+                        }
+                    } else {
+                        self.uses[index] = None;
+                    }
+                }
+            }
+        }
+        // Check if the collection is used for anything else
+        if path_to_local_id(expr, self.target) {
+            self.seen_other = true;
+        } else {
+            walk_expr(self, expr);
+        }
+    }
+}
+
+enum LoopKind<'tcx> {
+    Conditional(&'tcx Expr<'tcx>),
+    Loop,
+}
+
+fn check_loop_kind<'tcx>(expr: &Expr<'tcx>) -> Option<LoopKind<'tcx>> {
+    if let Some(higher::WhileLet { let_expr, .. }) = higher::WhileLet::hir(expr) {
+        return Some(LoopKind::Conditional(let_expr));
+    }
+    if let Some(higher::While { condition, .. }) = higher::While::hir(expr) {
+        return Some(LoopKind::Conditional(condition));
+    }
+    if let Some(higher::ForLoop { arg, .. }) = higher::ForLoop::hir(expr) {
+        return Some(LoopKind::Conditional(arg));
+    }
+    if let ExprKind::Loop { .. } = expr.kind {
+        return Some(LoopKind::Loop);
+    }
+
+    None
+}
+
+impl<'tcx> IterFunctionVisitor<'_, 'tcx> {
+    fn visit_block_expr(&mut self, expr: &'tcx Expr<'tcx>, hir_id: Option<HirId>) {
+        self.current_statement_hir_id = hir_id;
+        self.current_mutably_captured_ids = get_captured_ids(self.cx, self.cx.typeck_results().expr_ty(expr));
+        self.visit_expr(expr);
+    }
+}
+
+fn get_expr_and_hir_id_from_stmt<'v>(stmt: &'v Stmt<'v>) -> Option<(&'v Expr<'v>, Option<HirId>)> {
+    match stmt.kind {
+        StmtKind::Expr(expr) | StmtKind::Semi(expr) => Some((expr, None)),
+        StmtKind::Item(..) => None,
+        StmtKind::Local(Local { init, pat, .. }) => {
+            if let PatKind::Binding(_, hir_id, ..) = pat.kind {
+                init.map(|init_expr| (init_expr, Some(hir_id)))
+            } else {
+                init.map(|init_expr| (init_expr, None))
+            }
+        },
+    }
+}
+
+struct UsedCountVisitor<'a, 'tcx> {
+    cx: &'a LateContext<'tcx>,
+    id: HirId,
+    count: usize,
+}
+
+impl<'a, 'tcx> Visitor<'tcx> for UsedCountVisitor<'a, 'tcx> {
+    type NestedFilter = nested_filter::OnlyBodies;
+
+    fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
+        if path_to_local_id(expr, self.id) {
+            self.count += 1;
+        } else {
+            walk_expr(self, expr);
+        }
+    }
+
+    fn nested_visit_map(&mut self) -> Self::Map {
+        self.cx.tcx.hir()
+    }
+}
+
+/// Detect the occurrences of calls to `iter` or `into_iter` for the
+/// given identifier
+fn detect_iter_and_into_iters<'tcx: 'a, 'a>(
+    block: &'tcx Block<'tcx>,
+    id: HirId,
+    cx: &'a LateContext<'tcx>,
+    captured_ids: HirIdSet,
+) -> Option<Vec<IterFunction>> {
+    let mut visitor = IterFunctionVisitor {
+        uses: Vec::new(),
+        target: id,
+        seen_other: false,
+        cx,
+        current_mutably_captured_ids: HirIdSet::default(),
+        illegal_mutable_capture_ids: captured_ids,
+        hir_id_uses_map: FxHashMap::default(),
+        current_statement_hir_id: None,
+    };
+    visitor.visit_block(block);
+    if visitor.seen_other {
+        None
+    } else {
+        Some(visitor.uses.into_iter().flatten().collect())
+    }
+}
+
+fn get_captured_ids(cx: &LateContext<'_>, ty: Ty<'_>) -> HirIdSet {
+    fn get_captured_ids_recursive(cx: &LateContext<'_>, ty: Ty<'_>, set: &mut HirIdSet) {
+        match ty.kind() {
+            ty::Adt(_, generics) => {
+                for generic in *generics {
+                    if let GenericArgKind::Type(ty) = generic.unpack() {
+                        get_captured_ids_recursive(cx, ty, set);
+                    }
+                }
+            },
+            ty::Closure(def_id, _) => {
+                let closure_hir_node = cx.tcx.hir().get_if_local(*def_id).unwrap();
+                if let Node::Expr(closure_expr) = closure_hir_node {
+                    can_move_expr_to_closure(cx, closure_expr)
+                        .unwrap()
+                        .into_iter()
+                        .for_each(|(hir_id, capture_kind)| {
+                            if matches!(capture_kind, CaptureKind::Ref(Mutability::Mut)) {
+                                set.insert(hir_id);
+                            }
+                        });
+                }
+            },
+            _ => (),
+        }
+    }
+
+    let mut set = HirIdSet::default();
+
+    get_captured_ids_recursive(cx, ty, &mut set);
+
+    set
+}
diff --git a/clippy_lints/src/methods/option_as_ref_deref.rs b/clippy_lints/src/methods/option_as_ref_deref.rs
index 742483e6b2e..e6eb64bcbde 100644
--- a/clippy_lints/src/methods/option_as_ref_deref.rs
+++ b/clippy_lints/src/methods/option_as_ref_deref.rs
@@ -13,8 +13,8 @@ use rustc_span::sym;
 use super::OPTION_AS_REF_DEREF;
 
 /// lint use of `_.as_ref().map(Deref::deref)` for `Option`s
-pub(super) fn check<'tcx>(
-    cx: &LateContext<'tcx>,
+pub(super) fn check(
+    cx: &LateContext<'_>,
     expr: &hir::Expr<'_>,
     as_ref_recv: &hir::Expr<'_>,
     map_arg: &hir::Expr<'_>,
diff --git a/clippy_lints/src/methods/or_fun_call.rs b/clippy_lints/src/methods/or_fun_call.rs
index 991d3dd538b..4460f38fcc1 100644
--- a/clippy_lints/src/methods/or_fun_call.rs
+++ b/clippy_lints/src/methods/or_fun_call.rs
@@ -83,6 +83,8 @@ pub(super) fn check<'tcx>(
         method_span: Span,
         self_expr: &hir::Expr<'_>,
         arg: &'tcx hir::Expr<'_>,
+        // `Some` if fn has second argument
+        second_arg: Option<&hir::Expr<'_>>,
         span: Span,
         // None if lambda is required
         fun_span: Option<Span>,
@@ -109,30 +111,40 @@ pub(super) fn check<'tcx>(
             if poss.contains(&name);
 
             then {
-                let macro_expanded_snipped;
-                let sugg: Cow<'_, str> = {
+                let sugg = {
                     let (snippet_span, use_lambda) = match (fn_has_arguments, fun_span) {
                         (false, Some(fun_span)) => (fun_span, false),
                         _ => (arg.span, true),
                     };
-                    let snippet = {
-                        let not_macro_argument_snippet = snippet_with_macro_callsite(cx, snippet_span, "..");
-                        if not_macro_argument_snippet == "vec![]" {
-                            macro_expanded_snipped = snippet(cx, snippet_span, "..");
+
+                    let format_span = |span: Span| {
+                        let not_macro_argument_snippet = snippet_with_macro_callsite(cx, span, "..");
+                        let snip = if not_macro_argument_snippet == "vec![]" {
+                            let macro_expanded_snipped = snippet(cx, snippet_span, "..");
                             match macro_expanded_snipped.strip_prefix("$crate::vec::") {
-                                Some(stripped) => Cow::from(stripped),
+                                Some(stripped) => Cow::Owned(stripped.to_owned()),
                                 None => macro_expanded_snipped,
                             }
                         } else {
                             not_macro_argument_snippet
-                        }
+                        };
+
+                        snip.to_string()
                     };
 
-                    if use_lambda {
+                    let snip = format_span(snippet_span);
+                    let snip = if use_lambda {
                         let l_arg = if fn_has_arguments { "_" } else { "" };
-                        format!("|{l_arg}| {snippet}").into()
+                        format!("|{l_arg}| {snip}")
                     } else {
-                        snippet
+                        snip
+                    };
+
+                    if let Some(f) = second_arg {
+                        let f = format_span(f.span);
+                        format!("{snip}, {f}")
+                    } else {
+                        snip
                     }
                 };
                 let span_replace_word = method_span.with_hi(span.hi());
@@ -149,8 +161,8 @@ pub(super) fn check<'tcx>(
         }
     }
 
-    if let [arg] = args {
-        let inner_arg = if let hir::ExprKind::Block(
+    let extract_inner_arg = |arg: &'tcx hir::Expr<'_>| {
+        if let hir::ExprKind::Block(
             hir::Block {
                 stmts: [],
                 expr: Some(expr),
@@ -162,19 +174,32 @@ pub(super) fn check<'tcx>(
             expr
         } else {
             arg
-        };
+        }
+    };
+
+    if let [arg] = args {
+        let inner_arg = extract_inner_arg(arg);
         match inner_arg.kind {
             hir::ExprKind::Call(fun, or_args) => {
                 let or_has_args = !or_args.is_empty();
                 if !check_unwrap_or_default(cx, name, fun, arg, or_has_args, expr.span, method_span) {
                     let fun_span = if or_has_args { None } else { Some(fun.span) };
-                    check_general_case(cx, name, method_span, receiver, arg, expr.span, fun_span);
+                    check_general_case(cx, name, method_span, receiver, arg, None, expr.span, fun_span);
                 }
             },
             hir::ExprKind::Index(..) | hir::ExprKind::MethodCall(..) => {
-                check_general_case(cx, name, method_span, receiver, arg, expr.span, None);
+                check_general_case(cx, name, method_span, receiver, arg, None, expr.span, None);
             },
             _ => (),
         }
     }
+
+    // `map_or` takes two arguments
+    if let [arg, lambda] = args {
+        let inner_arg = extract_inner_arg(arg);
+        if let hir::ExprKind::Call(fun, or_args) = inner_arg.kind {
+            let fun_span = if or_args.is_empty() { Some(fun.span) } else { None };
+            check_general_case(cx, name, method_span, receiver, arg, Some(lambda), expr.span, fun_span);
+        }
+    }
 }
diff --git a/clippy_lints/src/methods/seek_from_current.rs b/clippy_lints/src/methods/seek_from_current.rs
new file mode 100644
index 00000000000..361a3082f94
--- /dev/null
+++ b/clippy_lints/src/methods/seek_from_current.rs
@@ -0,0 +1,48 @@
+use rustc_ast::ast::{LitIntType, LitKind};
+use rustc_errors::Applicability;
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::LateContext;
+
+use clippy_utils::{
+    diagnostics::span_lint_and_sugg, get_trait_def_id, match_def_path, paths, source::snippet_with_applicability,
+    ty::implements_trait,
+};
+
+use super::SEEK_FROM_CURRENT;
+
+pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, recv: &'tcx Expr<'_>, arg: &'tcx Expr<'_>) {
+    let ty = cx.typeck_results().expr_ty(recv);
+
+    if let Some(def_id) = get_trait_def_id(cx, &paths::STD_IO_SEEK) {
+        if implements_trait(cx, ty, def_id, &[]) && arg_is_seek_from_current(cx, arg) {
+            let mut applicability = Applicability::MachineApplicable;
+            let snip = snippet_with_applicability(cx, recv.span, "..", &mut applicability);
+
+            span_lint_and_sugg(
+                cx,
+                SEEK_FROM_CURRENT,
+                expr.span,
+                "using `SeekFrom::Current` to start from current position",
+                "replace with",
+                format!("{snip}.stream_position()"),
+                applicability,
+            );
+        }
+    }
+}
+
+fn arg_is_seek_from_current<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> bool {
+    if let ExprKind::Call(f, args) = expr.kind &&
+        let ExprKind::Path(ref path) = f.kind &&
+        let Some(def_id) = cx.qpath_res(path, f.hir_id).opt_def_id() &&
+        match_def_path(cx, def_id, &paths::STD_IO_SEEK_FROM_CURRENT) {
+        // check if argument of `SeekFrom::Current` is `0`
+        if args.len() == 1 &&
+            let ExprKind::Lit(ref lit) = args[0].kind &&
+            let LitKind::Int(0, LitIntType::Unsuffixed) = lit.node {
+            return true
+        }
+    }
+
+    false
+}
diff --git a/clippy_lints/src/methods/seek_to_start_instead_of_rewind.rs b/clippy_lints/src/methods/seek_to_start_instead_of_rewind.rs
new file mode 100644
index 00000000000..7e3bed1e41a
--- /dev/null
+++ b/clippy_lints/src/methods/seek_to_start_instead_of_rewind.rs
@@ -0,0 +1,45 @@
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::ty::implements_trait;
+use clippy_utils::{get_trait_def_id, match_def_path, paths};
+use rustc_ast::ast::{LitIntType, LitKind};
+use rustc_errors::Applicability;
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::LateContext;
+use rustc_span::Span;
+
+use super::SEEK_TO_START_INSTEAD_OF_REWIND;
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx Expr<'_>,
+    recv: &'tcx Expr<'_>,
+    arg: &'tcx Expr<'_>,
+    name_span: Span,
+) {
+    // Get receiver type
+    let ty = cx.typeck_results().expr_ty(recv).peel_refs();
+
+    if let Some(seek_trait_id) = get_trait_def_id(cx, &paths::STD_IO_SEEK) &&
+        implements_trait(cx, ty, seek_trait_id, &[]) &&
+        let ExprKind::Call(func, args1) = arg.kind &&
+        let ExprKind::Path(ref path) = func.kind &&
+        let Some(def_id) = cx.qpath_res(path, func.hir_id).opt_def_id() &&
+        match_def_path(cx, def_id, &paths::STD_IO_SEEKFROM_START) &&
+        args1.len() == 1 &&
+        let ExprKind::Lit(ref lit) = args1[0].kind &&
+        let LitKind::Int(0, LitIntType::Unsuffixed) = lit.node
+    {
+        let method_call_span = expr.span.with_lo(name_span.lo());
+        span_lint_and_then(
+            cx,
+            SEEK_TO_START_INSTEAD_OF_REWIND,
+            method_call_span,
+            "used `seek` to go to the start of the stream",
+            |diag| {
+                let app = Applicability::MachineApplicable;
+
+                diag.span_suggestion(method_call_span, "replace with", "rewind()", app);
+            },
+        );
+    }
+}
diff --git a/clippy_lints/src/methods/string_extend_chars.rs b/clippy_lints/src/methods/string_extend_chars.rs
index 6f4cec546e9..f35d81cee8e 100644
--- a/clippy_lints/src/methods/string_extend_chars.rs
+++ b/clippy_lints/src/methods/string_extend_chars.rs
@@ -18,7 +18,11 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr
         let target = &arglists[0].0;
         let self_ty = cx.typeck_results().expr_ty(target).peel_refs();
         let ref_str = if *self_ty.kind() == ty::Str {
-            ""
+            if matches!(target.kind, hir::ExprKind::Index(..)) {
+                "&"
+            } else {
+                ""
+            }
         } else if is_type_lang_item(cx, self_ty, hir::LangItem::String) {
             "&"
         } else {
diff --git a/clippy_lints/src/methods/suspicious_map.rs b/clippy_lints/src/methods/suspicious_map.rs
index 851cdf54455..2ac0786b37b 100644
--- a/clippy_lints/src/methods/suspicious_map.rs
+++ b/clippy_lints/src/methods/suspicious_map.rs
@@ -8,7 +8,7 @@ use rustc_span::sym;
 
 use super::SUSPICIOUS_MAP;
 
-pub fn check<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, count_recv: &hir::Expr<'_>, map_arg: &hir::Expr<'_>) {
+pub fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, count_recv: &hir::Expr<'_>, map_arg: &hir::Expr<'_>) {
     if_chain! {
         if is_trait_method(cx, count_recv, sym::Iterator);
         let closure = expr_or_init(cx, map_arg);
diff --git a/clippy_lints/src/methods/unnecessary_join.rs b/clippy_lints/src/methods/unnecessary_join.rs
index c9b87bc6bf2..087e1e4343b 100644
--- a/clippy_lints/src/methods/unnecessary_join.rs
+++ b/clippy_lints/src/methods/unnecessary_join.rs
@@ -31,7 +31,7 @@ pub(super) fn check<'tcx>(
                 cx,
                 UNNECESSARY_JOIN,
                 span.with_hi(expr.span.hi()),
-                r#"called `.collect<Vec<String>>().join("")` on an iterator"#,
+                r#"called `.collect::<Vec<String>>().join("")` on an iterator"#,
                 "try using",
                 "collect::<String>()".to_owned(),
                 applicability,
diff --git a/clippy_lints/src/methods/unwrap_used.rs b/clippy_lints/src/methods/unwrap_used.rs
index ee17f2d7889..90983f249cd 100644
--- a/clippy_lints/src/methods/unwrap_used.rs
+++ b/clippy_lints/src/methods/unwrap_used.rs
@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_help;
 use clippy_utils::ty::is_type_diagnostic_item;
-use clippy_utils::{is_in_test_function, is_lint_allowed};
+use clippy_utils::{is_in_cfg_test, is_lint_allowed};
 use rustc_hir as hir;
 use rustc_lint::LateContext;
 use rustc_span::sym;
@@ -18,16 +18,16 @@ pub(super) fn check(
     let obj_ty = cx.typeck_results().expr_ty(recv).peel_refs();
 
     let mess = if is_type_diagnostic_item(cx, obj_ty, sym::Option) && !is_err {
-        Some((UNWRAP_USED, "an Option", "None", ""))
+        Some((UNWRAP_USED, "an `Option`", "None", ""))
     } else if is_type_diagnostic_item(cx, obj_ty, sym::Result) {
-        Some((UNWRAP_USED, "a Result", if is_err { "Ok" } else { "Err" }, "an "))
+        Some((UNWRAP_USED, "a `Result`", if is_err { "Ok" } else { "Err" }, "an "))
     } else {
         None
     };
 
     let method_suffix = if is_err { "_err" } else { "" };
 
-    if allow_unwrap_in_tests && is_in_test_function(cx.tcx, expr.hir_id) {
+    if allow_unwrap_in_tests && is_in_cfg_test(cx.tcx, expr.hir_id) {
         return;
     }
 
@@ -45,7 +45,7 @@ pub(super) fn check(
             cx,
             lint,
             expr.span,
-            &format!("used `unwrap{method_suffix}()` on `{kind}` value"),
+            &format!("used `unwrap{method_suffix}()` on {kind} value"),
             None,
             &help,
         );