1 files changed, 93 insertions, 0 deletions
diff --git a/src/tools/clippy/tests/ui/const_comparisons.rs b/src/tools/clippy/tests/ui/const_comparisons.rs
new file mode 100644
index 000000000..8e265c914
--- /dev/null
+++ b/src/tools/clippy/tests/ui/const_comparisons.rs
@@ -0,0 +1,93 @@
+#![allow(unused)]
+#![warn(clippy::impossible_comparisons)]
+#![warn(clippy::redundant_comparisons)]
+#![allow(clippy::no_effect)]
+#![allow(clippy::short_circuit_statement)]
+#![allow(clippy::manual_range_contains)]
+
+const STATUS_BAD_REQUEST: u16 = 400;
+const STATUS_SERVER_ERROR: u16 = 500;
+
+struct Status {
+    code: u16,
+}
+
+impl PartialEq<u16> for Status {
+    fn eq(&self, other: &u16) -> bool {
+        self.code == *other
+    }
+}
+
+impl PartialOrd<u16> for Status {
+    fn partial_cmp(&self, other: &u16) -> Option<std::cmp::Ordering> {
+        self.code.partial_cmp(other)
+    }
+}
+
+impl PartialEq<Status> for u16 {
+    fn eq(&self, other: &Status) -> bool {
+        *self == other.code
+    }
+}
+
+impl PartialOrd<Status> for u16 {
+    fn partial_cmp(&self, other: &Status) -> Option<std::cmp::Ordering> {
+        self.partial_cmp(&other.code)
+    }
+}
+
+fn main() {
+    let status_code = 500; // Value doesn't matter for the lint
+    let status = Status { code: status_code };
+
+    status_code >= 400 && status_code < 500; // Correct
+    status_code <= 400 && status_code > 500;
+    status_code > 500 && status_code < 400;
+    status_code < 500 && status_code > 500;
+
+    // More complex expressions
+    status_code < { 400 } && status_code > { 500 };
+    status_code < STATUS_BAD_REQUEST && status_code > STATUS_SERVER_ERROR;
+    status_code <= u16::MIN + 1 && status_code > STATUS_SERVER_ERROR;
+    status_code < STATUS_SERVER_ERROR && status_code > STATUS_SERVER_ERROR;
+
+    // Comparing two different types, via the `impl PartialOrd<u16> for Status`
+    status < { 400 } && status > { 500 };
+    status < STATUS_BAD_REQUEST && status > STATUS_SERVER_ERROR;
+    status <= u16::MIN + 1 && status > STATUS_SERVER_ERROR;
+    status < STATUS_SERVER_ERROR && status > STATUS_SERVER_ERROR;
+
+    // Yoda conditions
+    500 <= status_code && 600 > status_code; // Correct
+    500 <= status_code && status_code <= 600; // Correct
+    500 >= status_code && 600 < status_code; // Incorrect
+    500 >= status_code && status_code > 600; // Incorrect
+
+    // Yoda conditions, comparing two different types
+    500 <= status && 600 > status; // Correct
+    500 <= status && status <= 600; // Correct
+    500 >= status && 600 < status; // Incorrect
+    500 >= status && status > 600; // Incorrect
+
+    // Expressions where one of the sides has no effect
+    status_code < 200 && status_code <= 299;
+    status_code > 200 && status_code >= 299;
+
+    status_code >= 500 && status_code > 500; // Useless left
+    status_code > 500 && status_code >= 500; // Useless right
+    status_code <= 500 && status_code < 500; // Useless left
+    status_code < 500 && status_code <= 500; // Useless right
+
+    // Other types
+    let name = "Steve";
+    name < "Jennifer" && name > "Shannon";
+
+    let numbers = [1, 2];
+    numbers < [3, 4] && numbers > [5, 6];
+
+    let letter = 'a';
+    letter < 'b' && letter > 'c';
+
+    let area = 42.0;
+    area < std::f32::consts::E && area > std::f32::consts::PI;
+}