Auto merge of #11757 - matthri:iter-kv-map-msrv-fix, r=Alexendoo

Fix iter_kv_map false positive into_keys and into_values suggestion

fixes: #11752

changelog: [`iter_kv_map`]: fix false positive: Don't suggest `into_keys()` and `into_values()` if the MSRV is to low

8 files changed, 156 insertions, 3 deletions

diff --git a/book/src/lint_configuration.md b/book/src/lint_configuration.md
index eaef074b8c5..2bb89321cef 100644
--- a/book/src/lint_configuration.md
+++ b/book/src/lint_configuration.md
@@ -150,6 +150,7 @@ The minimum rust version that the project supports. Defaults to the `rust-versio
 * [`tuple_array_conversions`](https://rust-lang.github.io/rust-clippy/master/index.html#tuple_array_conversions)
 * [`manual_try_fold`](https://rust-lang.github.io/rust-clippy/master/index.html#manual_try_fold)
 * [`manual_hash_one`](https://rust-lang.github.io/rust-clippy/master/index.html#manual_hash_one)
+* [`iter_kv_map`](https://rust-lang.github.io/rust-clippy/master/index.html#iter_kv_map)
 
 
 ## `cognitive-complexity-threshold`
diff --git a/clippy_config/src/conf.rs b/clippy_config/src/conf.rs
index 064cb0426b4..88611eb7087 100644
--- a/clippy_config/src/conf.rs
+++ b/clippy_config/src/conf.rs
@@ -249,7 +249,7 @@ define_Conf! {
     ///
     /// Suppress lints whenever the suggested change would cause breakage for other crates.
     (avoid_breaking_exported_api: bool = true),
-    /// Lint: MANUAL_SPLIT_ONCE, MANUAL_STR_REPEAT, CLONED_INSTEAD_OF_COPIED, REDUNDANT_FIELD_NAMES, OPTION_MAP_UNWRAP_OR, REDUNDANT_STATIC_LIFETIMES, FILTER_MAP_NEXT, CHECKED_CONVERSIONS, MANUAL_RANGE_CONTAINS, USE_SELF, MEM_REPLACE_WITH_DEFAULT, MANUAL_NON_EXHAUSTIVE, OPTION_AS_REF_DEREF, MAP_UNWRAP_OR, MATCH_LIKE_MATCHES_MACRO, MANUAL_STRIP, MISSING_CONST_FOR_FN, UNNESTED_OR_PATTERNS, FROM_OVER_INTO, PTR_AS_PTR, IF_THEN_SOME_ELSE_NONE, APPROX_CONSTANT, DEPRECATED_CFG_ATTR, INDEX_REFUTABLE_SLICE, MAP_CLONE, BORROW_AS_PTR, MANUAL_BITS, ERR_EXPECT, CAST_ABS_TO_UNSIGNED, UNINLINED_FORMAT_ARGS, MANUAL_CLAMP, MANUAL_LET_ELSE, UNCHECKED_DURATION_SUBTRACTION, COLLAPSIBLE_STR_REPLACE, SEEK_FROM_CURRENT, SEEK_REWIND, UNNECESSARY_LAZY_EVALUATIONS, TRANSMUTE_PTR_TO_REF, ALMOST_COMPLETE_RANGE, NEEDLESS_BORROW, DERIVABLE_IMPLS, MANUAL_IS_ASCII_CHECK, MANUAL_REM_EUCLID, MANUAL_RETAIN, TYPE_REPETITION_IN_BOUNDS, TUPLE_ARRAY_CONVERSIONS, MANUAL_TRY_FOLD, MANUAL_HASH_ONE.
+    /// Lint: MANUAL_SPLIT_ONCE, MANUAL_STR_REPEAT, CLONED_INSTEAD_OF_COPIED, REDUNDANT_FIELD_NAMES, OPTION_MAP_UNWRAP_OR, REDUNDANT_STATIC_LIFETIMES, FILTER_MAP_NEXT, CHECKED_CONVERSIONS, MANUAL_RANGE_CONTAINS, USE_SELF, MEM_REPLACE_WITH_DEFAULT, MANUAL_NON_EXHAUSTIVE, OPTION_AS_REF_DEREF, MAP_UNWRAP_OR, MATCH_LIKE_MATCHES_MACRO, MANUAL_STRIP, MISSING_CONST_FOR_FN, UNNESTED_OR_PATTERNS, FROM_OVER_INTO, PTR_AS_PTR, IF_THEN_SOME_ELSE_NONE, APPROX_CONSTANT, DEPRECATED_CFG_ATTR, INDEX_REFUTABLE_SLICE, MAP_CLONE, BORROW_AS_PTR, MANUAL_BITS, ERR_EXPECT, CAST_ABS_TO_UNSIGNED, UNINLINED_FORMAT_ARGS, MANUAL_CLAMP, MANUAL_LET_ELSE, UNCHECKED_DURATION_SUBTRACTION, COLLAPSIBLE_STR_REPLACE, SEEK_FROM_CURRENT, SEEK_REWIND, UNNECESSARY_LAZY_EVALUATIONS, TRANSMUTE_PTR_TO_REF, ALMOST_COMPLETE_RANGE, NEEDLESS_BORROW, DERIVABLE_IMPLS, MANUAL_IS_ASCII_CHECK, MANUAL_REM_EUCLID, MANUAL_RETAIN, TYPE_REPETITION_IN_BOUNDS, TUPLE_ARRAY_CONVERSIONS, MANUAL_TRY_FOLD, MANUAL_HASH_ONE, ITER_KV_MAP.
     ///
     /// The minimum rust version that the project supports. Defaults to the `rust-version` field in `Cargo.toml`
     #[default_text = ""]
diff --git a/clippy_config/src/msrvs.rs b/clippy_config/src/msrvs.rs
index 011d54629d4..b3ef666e306 100644
--- a/clippy_config/src/msrvs.rs
+++ b/clippy_config/src/msrvs.rs
@@ -23,6 +23,7 @@ msrv_aliases! {
     1,62,0 { BOOL_THEN_SOME, DEFAULT_ENUM_ATTRIBUTE }
     1,58,0 { FORMAT_ARGS_CAPTURE, PATTERN_TRAIT_CHAR_ARRAY }
     1,55,0 { SEEK_REWIND }
+    1,54,0 { INTO_KEYS }
     1,53,0 { OR_PATTERNS, MANUAL_BITS, BTREE_MAP_RETAIN, BTREE_SET_RETAIN, ARRAY_INTO_ITERATOR }
     1,52,0 { STR_SPLIT_ONCE, REM_EUCLID_CONST }
     1,51,0 { BORROW_AS_PTR, SEEK_FROM_CURRENT, UNSIGNED_ABS }
diff --git a/clippy_lints/src/methods/iter_kv_map.rs b/clippy_lints/src/methods/iter_kv_map.rs
index c5dbb6ad98b..e1b934d36ea 100644
--- a/clippy_lints/src/methods/iter_kv_map.rs
+++ b/clippy_lints/src/methods/iter_kv_map.rs
@@ -1,6 +1,7 @@
 #![allow(unused_imports)]
 
 use super::ITER_KV_MAP;
+use clippy_config::msrvs::{self, Msrv};
 use clippy_utils::diagnostics::{multispan_sugg, span_lint_and_sugg, span_lint_and_then};
 use clippy_utils::source::{snippet, snippet_with_applicability};
 use clippy_utils::ty::is_type_diagnostic_item;
@@ -21,7 +22,11 @@ pub(super) fn check<'tcx>(
     expr: &'tcx Expr<'tcx>,  // .iter().map(|(_, v_| v))
     recv: &'tcx Expr<'tcx>,  // hashmap
     m_arg: &'tcx Expr<'tcx>, // |(_, v)| v
+    msrv: &Msrv,
 ) {
+    if map_type == "into_iter" && !msrv.meets(msrvs::INTO_KEYS) {
+        return;
+    }
     if !expr.span.from_expansion()
         && let ExprKind::Closure(c) = m_arg.kind
         && let Body {
diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs
index 9ea2f6448b6..82cd3ac0486 100644
--- a/clippy_lints/src/methods/mod.rs
+++ b/clippy_lints/src/methods/mod.rs
@@ -4301,7 +4301,7 @@ impl Methods {
                         map_clone::check(cx, expr, recv, m_arg, &self.msrv);
                         match method_call(recv) {
                             Some((map_name @ ("iter" | "into_iter"), recv2, _, _, _)) => {
-                                iter_kv_map::check(cx, map_name, expr, recv2, m_arg);
+                                iter_kv_map::check(cx, map_name, expr, recv2, m_arg, &self.msrv);
                             },
                             Some(("cloned", recv2, [], _, _)) => iter_overeager_cloned::check(
                                 cx,
diff --git a/tests/ui/iter_kv_map.fixed b/tests/ui/iter_kv_map.fixed
index 566a5b690d8..2cbf972fca5 100644
--- a/tests/ui/iter_kv_map.fixed
+++ b/tests/ui/iter_kv_map.fixed
@@ -89,3 +89,46 @@ fn main() {
     // Don't let a mut interfere.
     let _ = map.clone().into_values().count();
 }
+
+#[clippy::msrv = "1.53"]
+fn msrv_1_53() {
+    let map: HashMap<u32, u32> = HashMap::new();
+
+    // Don't lint because into_iter is not supported
+    let _ = map.clone().into_iter().map(|(key, _)| key).collect::<Vec<_>>();
+    let _ = map.clone().into_iter().map(|(key, _)| key + 2).collect::<Vec<_>>();
+
+    let _ = map.clone().into_iter().map(|(_, val)| val).collect::<Vec<_>>();
+    let _ = map.clone().into_iter().map(|(_, val)| val + 2).collect::<Vec<_>>();
+
+    // Lint
+    let _ = map.keys().collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's keys
+    let _ = map.values().collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's values
+    let _ = map.values().map(|v| v + 2).collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's values
+}
+
+#[clippy::msrv = "1.54"]
+fn msrv_1_54() {
+    // Lint all
+    let map: HashMap<u32, u32> = HashMap::new();
+
+    let _ = map.clone().into_keys().collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's keys
+    let _ = map.clone().into_keys().map(|key| key + 2).collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's keys
+
+    let _ = map.clone().into_values().collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's values
+    let _ = map.clone().into_values().map(|val| val + 2).collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's values
+
+    let _ = map.keys().collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's keys
+    let _ = map.values().collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's values
+    let _ = map.values().map(|v| v + 2).collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's values
+}
diff --git a/tests/ui/iter_kv_map.rs b/tests/ui/iter_kv_map.rs
index d85e501da48..6a9a4267a76 100644
--- a/tests/ui/iter_kv_map.rs
+++ b/tests/ui/iter_kv_map.rs
@@ -93,3 +93,46 @@ fn main() {
     // Don't let a mut interfere.
     let _ = map.clone().into_iter().map(|(_, mut val)| val).count();
 }
+
+#[clippy::msrv = "1.53"]
+fn msrv_1_53() {
+    let map: HashMap<u32, u32> = HashMap::new();
+
+    // Don't lint because into_iter is not supported
+    let _ = map.clone().into_iter().map(|(key, _)| key).collect::<Vec<_>>();
+    let _ = map.clone().into_iter().map(|(key, _)| key + 2).collect::<Vec<_>>();
+
+    let _ = map.clone().into_iter().map(|(_, val)| val).collect::<Vec<_>>();
+    let _ = map.clone().into_iter().map(|(_, val)| val + 2).collect::<Vec<_>>();
+
+    // Lint
+    let _ = map.iter().map(|(key, _)| key).collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's keys
+    let _ = map.iter().map(|(_, value)| value).collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's values
+    let _ = map.iter().map(|(_, v)| v + 2).collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's values
+}
+
+#[clippy::msrv = "1.54"]
+fn msrv_1_54() {
+    // Lint all
+    let map: HashMap<u32, u32> = HashMap::new();
+
+    let _ = map.clone().into_iter().map(|(key, _)| key).collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's keys
+    let _ = map.clone().into_iter().map(|(key, _)| key + 2).collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's keys
+
+    let _ = map.clone().into_iter().map(|(_, val)| val).collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's values
+    let _ = map.clone().into_iter().map(|(_, val)| val + 2).collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's values
+
+    let _ = map.iter().map(|(key, _)| key).collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's keys
+    let _ = map.iter().map(|(_, value)| value).collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's values
+    let _ = map.iter().map(|(_, v)| v + 2).collect::<Vec<_>>();
+    //~^ ERROR: iterating on a map's values
+}
diff --git a/tests/ui/iter_kv_map.stderr b/tests/ui/iter_kv_map.stderr
index 62155b7f838..471615978e1 100644
--- a/tests/ui/iter_kv_map.stderr
+++ b/tests/ui/iter_kv_map.stderr
@@ -201,5 +201,65 @@ error: iterating on a map's values
 LL |     let _ = map.clone().into_iter().map(|(_, mut val)| val).count();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.clone().into_values()`
 
-error: aborting due to 28 previous errors
+error: iterating on a map's keys
+  --> $DIR/iter_kv_map.rs:109:13
+   |
+LL |     let _ = map.iter().map(|(key, _)| key).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.keys()`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:111:13
+   |
+LL |     let _ = map.iter().map(|(_, value)| value).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.values()`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:113:13
+   |
+LL |     let _ = map.iter().map(|(_, v)| v + 2).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.values().map(|v| v + 2)`
+
+error: iterating on a map's keys
+  --> $DIR/iter_kv_map.rs:122:13
+   |
+LL |     let _ = map.clone().into_iter().map(|(key, _)| key).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.clone().into_keys()`
+
+error: iterating on a map's keys
+  --> $DIR/iter_kv_map.rs:124:13
+   |
+LL |     let _ = map.clone().into_iter().map(|(key, _)| key + 2).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.clone().into_keys().map(|key| key + 2)`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:127:13
+   |
+LL |     let _ = map.clone().into_iter().map(|(_, val)| val).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.clone().into_values()`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:129:13
+   |
+LL |     let _ = map.clone().into_iter().map(|(_, val)| val + 2).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.clone().into_values().map(|val| val + 2)`
+
+error: iterating on a map's keys
+  --> $DIR/iter_kv_map.rs:132:13
+   |
+LL |     let _ = map.iter().map(|(key, _)| key).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.keys()`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:134:13
+   |
+LL |     let _ = map.iter().map(|(_, value)| value).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.values()`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:136:13
+   |
+LL |     let _ = map.iter().map(|(_, v)| v + 2).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.values().map(|v| v + 2)`
+
+error: aborting due to 38 previous errors