add support for unequal types

Author: Jacherr

clippy_lints/src/matches/mod.rs

@@ -23,6 +23,7 @@ mod significant_drop_in_scrutinee;
 mod single_match;
 mod try_err;
 mod wild_in_or_pats;
+mod unnecessary_pattern_matching;
 
 use clippy_config::msrvs::{self, Msrv};
 use clippy_utils::source::{snippet_opt, walk_span_to_context};

clippy_lints/src/matches/unnecessary_pattern_matching.rs

@@ -0,0 +1 @@
+use super::super::methods::UNNECESSARY_PATTERN_MATCHING;

clippy_lints/src/methods/unnecessary_pattern_matching.rs

@@ -15,7 +15,8 @@ use super::UNNECESSARY_PATTERN_MATCHING;
 // Only checking map_or for now
 pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, recv: &Expr<'_>, def: &Expr<'_>, map: &Expr<'_>) {
     if let ExprKind::Lit(def_kind) = def.kind
-    && let recv_ty = cx.typeck_results().expr_ty(recv)
+    && let typeck_results = cx.typeck_results()
+    && let recv_ty = typeck_results.expr_ty(recv)
     && (is_type_diagnostic_item(cx, recv_ty, sym::Option)
         || is_type_diagnostic_item(cx, recv_ty, sym::Result))
     && let Bool(def_bool) = def_kind.node
@@ -46,7 +47,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, recv: &Expr<'_>, def:
         // expensive computation inside of it
         if is_local_used(cx, non_binding_location, hir_id) 
             || !switch_to_eager_eval(cx, non_binding_location)
-            || l.kind {
+            || typeck_results.expr_ty(l) != typeck_results.expr_ty(r) {
             return;
         };
         span_lint_and_sugg(

tests/ui/iter_over_hash_type.stderr

@@ -0,0 +1,53 @@
+error: iterating over unordered hash-based type
+  --> $DIR/iter_over_hash_type.rs:13:5
+   |
+LL | /     for x in &hash_set {
+LL | |         let _ = x;
+LL | |     }
+   | |_____^
+   |
+   = note: `-D clippy::iter-over-hash-type` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::iter_over_hash_type)]`
+
+error: iterating over unordered hash-based type
+  --> $DIR/iter_over_hash_type.rs:16:5
+   |
+LL | /     for x in hash_set.iter() {
+LL | |         let _ = x;
+LL | |     }
+   | |_____^
+
+error: iterating over unordered hash-based type
+  --> $DIR/iter_over_hash_type.rs:19:5
+   |
+LL | /     for x in hash_set {
+LL | |         let _ = x;
+LL | |     }
+   | |_____^
+
+error: iterating over unordered hash-based type
+  --> $DIR/iter_over_hash_type.rs:22:5
+   |
+LL | /     for (x, y) in &hash_map {
+LL | |         let _ = (x, y);
+LL | |     }
+   | |_____^
+
+error: iterating over unordered hash-based type
+  --> $DIR/iter_over_hash_type.rs:25:5
+   |
+LL | /     for x in hash_map.keys() {
+LL | |         let _ = x;
+LL | |     }
+   | |_____^
+
+error: iterating over unordered hash-based type
+  --> $DIR/iter_over_hash_type.rs:28:5
+   |
+LL | /     for x in hash_map.values() {
+LL | |         let _ = x;
+LL | |     }
+   | |_____^
+
+error: aborting due to 6 previous errors
+

tests/ui/unnecessary_pattern_matching.rs

@@ -8,14 +8,14 @@ fn main() {
     let _ = Some(5).map_or(false, |n| 5 == n);
     let _ = Some(5).map_or(true, |n| n != 5);
     let _ = Some(5).map_or(true, |n| 5 != n);
-    let _ = Some(vec![5]).map_or(false, |n| n == [5]);
 
     // shouldnt trigger
     let _ = Some(5).map_or(true, |n| n == 5);
     let _ = Some(5).map_or(true, |n| 5 == n);
     let _ = Some(5).map_or(false, |n| n != 5);
     let _ = Some(5).map_or(false, |n| 5 != n);
     let _ = Some(5).map_or(false, |n| n == n);
+    let _ = Some(vec![5]).map_or(false, |n| n == [5]);
     let _ = Some(vec![1]).map_or(false, |n| vec![2] == n);
     let _ = Some(5).map_or(false, |n| n == if 2 > 1 { n } else { 0 });
 }