recognize contains calls on ranges

clippy_lints/src/transmute/eager_transmute.rs

@@ -36,11 +36,27 @@ fn range_fully_contained(from: WrappingRange, to: WrappingRange) -> bool {
 /// * `x < 4 && x > 1`
 /// * `x.field < 4 && x.field > 1` (given `x.field`)
 /// * `x.field < 4 && unrelated()`
+/// * `(1..=3).contains(&x)`
 fn binops_with_local(cx: &LateContext<'_>, local_expr: &Expr<'_>, expr: &Expr<'_>) -> bool {
     match expr.kind {
         ExprKind::Binary(_, lhs, rhs) => {
             binops_with_local(cx, local_expr, lhs) || binops_with_local(cx, local_expr, rhs)
         },
+        ExprKind::MethodCall(path, receiver, [arg], _)
+            if path.ident.name == sym!(contains)
+                // ... `contains` called on some kind of range
+                && let Some(receiver_adt) = cx.typeck_results().expr_ty(receiver).peel_refs().ty_adt_def()
+                && let lang_items = cx.tcx.lang_items()
+                && [
+                    lang_items.range_from_struct(),
+                    lang_items.range_inclusive_struct(),
+                    lang_items.range_struct(),
+                    lang_items.range_to_inclusive_struct(),
+                    lang_items.range_to_struct()
+                ].into_iter().any(|did| did == Some(receiver_adt.did())) =>
+        {
+            eq_expr_value(cx, local_expr, arg.peel_borrows())
+        },
         _ => eq_expr_value(cx, local_expr, expr),
     }
 }

tests/ui/eager_transmute.fixed

@@ -42,6 +42,19 @@ fn f(op: u8, op2: Data, unrelated: u8) {
 
     // don't lint: wrong variable
     let _: Option<Opcode> = (op2.foo[0] > 0 && op2.bar[1] < 10).then_some(unsafe { std::mem::transmute(op) });
+
+    // range contains checks
+    let _: Option<Opcode> = (1..=3).contains(&op).then(|| unsafe { std::mem::transmute(op) });
+    let _: Option<Opcode> = ((1..=3).contains(&op) || op == 4).then(|| unsafe { std::mem::transmute(op) });
+    let _: Option<Opcode> = (1..3).contains(&op).then(|| unsafe { std::mem::transmute(op) });
+    let _: Option<Opcode> = (1..).contains(&op).then(|| unsafe { std::mem::transmute(op) });
+    let _: Option<Opcode> = (..3).contains(&op).then(|| unsafe { std::mem::transmute(op) });
+    let _: Option<Opcode> = (..=3).contains(&op).then(|| unsafe { std::mem::transmute(op) });
+
+    // unrelated binding in contains
+    let _: Option<Opcode> = (1..=3)
+        .contains(&unrelated)
+        .then_some(unsafe { std::mem::transmute(op) });
 }
 
 unsafe fn f2(op: u8) {

tests/ui/eager_transmute.rs

@@ -42,6 +42,19 @@ fn f(op: u8, op2: Data, unrelated: u8) {
 
     // don't lint: wrong variable
     let _: Option<Opcode> = (op2.foo[0] > 0 && op2.bar[1] < 10).then_some(unsafe { std::mem::transmute(op) });
+
+    // range contains checks
+    let _: Option<Opcode> = (1..=3).contains(&op).then_some(unsafe { std::mem::transmute(op) });
+    let _: Option<Opcode> = ((1..=3).contains(&op) || op == 4).then_some(unsafe { std::mem::transmute(op) });
+    let _: Option<Opcode> = (1..3).contains(&op).then_some(unsafe { std::mem::transmute(op) });
+    let _: Option<Opcode> = (1..).contains(&op).then_some(unsafe { std::mem::transmute(op) });
+    let _: Option<Opcode> = (..3).contains(&op).then_some(unsafe { std::mem::transmute(op) });
+    let _: Option<Opcode> = (..=3).contains(&op).then_some(unsafe { std::mem::transmute(op) });
+
+    // unrelated binding in contains
+    let _: Option<Opcode> = (1..=3)
+        .contains(&unrelated)
+        .then_some(unsafe { std::mem::transmute(op) });
 }
 
 unsafe fn f2(op: u8) {

tests/ui/eager_transmute.stderr

@@ -78,7 +78,73 @@ LL |     let _: Option<Opcode> = (op2.foo[0] > 0 && op2.foo[0] < 10).then(|| uns
    |                                                                 ~~~~ ++
 
 error: this transmute is always evaluated eagerly, even if the condition is false
-  --> $DIR/eager_transmute.rs:48:24
+  --> $DIR/eager_transmute.rs:47:70
+   |
+LL |     let _: Option<Opcode> = (1..=3).contains(&op).then_some(unsafe { std::mem::transmute(op) });
+   |                                                                      ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: consider using `bool::then` to only transmute if the condition holds
+   |
+LL |     let _: Option<Opcode> = (1..=3).contains(&op).then(|| unsafe { std::mem::transmute(op) });
+   |                                                   ~~~~ ++
+
+error: this transmute is always evaluated eagerly, even if the condition is false
+  --> $DIR/eager_transmute.rs:48:83
+   |
+LL |     let _: Option<Opcode> = ((1..=3).contains(&op) || op == 4).then_some(unsafe { std::mem::transmute(op) });
+   |                                                                                   ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: consider using `bool::then` to only transmute if the condition holds
+   |
+LL |     let _: Option<Opcode> = ((1..=3).contains(&op) || op == 4).then(|| unsafe { std::mem::transmute(op) });
+   |                                                                ~~~~ ++
+
+error: this transmute is always evaluated eagerly, even if the condition is false
+  --> $DIR/eager_transmute.rs:49:69
+   |
+LL |     let _: Option<Opcode> = (1..3).contains(&op).then_some(unsafe { std::mem::transmute(op) });
+   |                                                                     ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: consider using `bool::then` to only transmute if the condition holds
+   |
+LL |     let _: Option<Opcode> = (1..3).contains(&op).then(|| unsafe { std::mem::transmute(op) });
+   |                                                  ~~~~ ++
+
+error: this transmute is always evaluated eagerly, even if the condition is false
+  --> $DIR/eager_transmute.rs:50:68
+   |
+LL |     let _: Option<Opcode> = (1..).contains(&op).then_some(unsafe { std::mem::transmute(op) });
+   |                                                                    ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: consider using `bool::then` to only transmute if the condition holds
+   |
+LL |     let _: Option<Opcode> = (1..).contains(&op).then(|| unsafe { std::mem::transmute(op) });
+   |                                                 ~~~~ ++
+
+error: this transmute is always evaluated eagerly, even if the condition is false
+  --> $DIR/eager_transmute.rs:51:68
+   |
+LL |     let _: Option<Opcode> = (..3).contains(&op).then_some(unsafe { std::mem::transmute(op) });
+   |                                                                    ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: consider using `bool::then` to only transmute if the condition holds
+   |
+LL |     let _: Option<Opcode> = (..3).contains(&op).then(|| unsafe { std::mem::transmute(op) });
+   |                                                 ~~~~ ++
+
+error: this transmute is always evaluated eagerly, even if the condition is false
+  --> $DIR/eager_transmute.rs:52:69
+   |
+LL |     let _: Option<Opcode> = (..=3).contains(&op).then_some(unsafe { std::mem::transmute(op) });
+   |                                                                     ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: consider using `bool::then` to only transmute if the condition holds
+   |
+LL |     let _: Option<Opcode> = (..=3).contains(&op).then(|| unsafe { std::mem::transmute(op) });
+   |                                                  ~~~~ ++
+
+error: this transmute is always evaluated eagerly, even if the condition is false
+  --> $DIR/eager_transmute.rs:61:24
    |
 LL |     (op < 4).then_some(std::mem::transmute::<_, Opcode>(op));
    |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -89,7 +155,7 @@ LL |     (op < 4).then(|| std::mem::transmute::<_, Opcode>(op));
    |              ~~~~ ++
 
 error: this transmute is always evaluated eagerly, even if the condition is false
-  --> $DIR/eager_transmute.rs:77:60
+  --> $DIR/eager_transmute.rs:90:60
    |
 LL |     let _: Option<NonZeroU8> = (v1 > 0).then_some(unsafe { std::mem::transmute(v1) });
    |                                                            ^^^^^^^^^^^^^^^^^^^^^^^
@@ -100,7 +166,7 @@ LL |     let _: Option<NonZeroU8> = (v1 > 0).then(|| unsafe { std::mem::transmut
    |                                         ~~~~ ++
 
 error: this transmute is always evaluated eagerly, even if the condition is false
-  --> $DIR/eager_transmute.rs:83:86
+  --> $DIR/eager_transmute.rs:96:86
    |
 LL |     let _: Option<NonMaxU8> = (v2 < NonZeroU8::new(255).unwrap()).then_some(unsafe { std::mem::transmute(v2) });
    |                                                                                      ^^^^^^^^^^^^^^^^^^^^^^^
@@ -111,7 +177,7 @@ LL |     let _: Option<NonMaxU8> = (v2 < NonZeroU8::new(255).unwrap()).then(|| u
    |                                                                   ~~~~ ++
 
 error: this transmute is always evaluated eagerly, even if the condition is false
-  --> $DIR/eager_transmute.rs:89:93
+  --> $DIR/eager_transmute.rs:102:93
    |
 LL |     let _: Option<NonZeroNonMaxU8> = (v2 < NonZeroU8::new(255).unwrap()).then_some(unsafe { std::mem::transmute(v2) });
    |                                                                                             ^^^^^^^^^^^^^^^^^^^^^^^
@@ -121,5 +187,5 @@ help: consider using `bool::then` to only transmute if the condition holds
 LL |     let _: Option<NonZeroNonMaxU8> = (v2 < NonZeroU8::new(255).unwrap()).then(|| unsafe { std::mem::transmute(v2) });
    |                                                                          ~~~~ ++
 
-error: aborting due to 11 previous errors
+error: aborting due to 17 previous errors