Make must_use lint cover all binary/unary operators

2 files changed, 184 insertions, 0 deletions

diff --git a/src/test/ui/lint/must-use-ops.rs b/src/test/ui/lint/must-use-ops.rs
new file mode 100644
index 00000000000..4ed82ab3b40
--- /dev/null
+++ b/src/test/ui/lint/must-use-ops.rs
@@ -0,0 +1,52 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Issue #50124 - Test warning for unused operator expressions
+
+// compile-pass
+
+#![feature(fn_must_use)]
+#![warn(unused_must_use)]
+
+fn main() {
+    let val = 1;
+    let val_pointer = &val;
+
+// Comparison Operators
+    val == 1;
+    val < 1;
+    val <= 1;
+    val != 1;
+    val >= 1;
+    val > 1;
+
+// Arithmetic Operators
+    val + 2;
+    val - 2;
+    val / 2;
+    val * 2;
+    val % 2;
+
+// Logical Operators
+    true && true;
+    false || true;
+
+// Bitwise Operators
+    5 ^ val;
+    5 & val;
+    5 | val;
+    5 << val;
+    5 >> val;
+
+// Unary Operators
+    !val;
+    -val;
+    *val_pointer;
+}
diff --git a/src/test/ui/lint/must-use-ops.stderr b/src/test/ui/lint/must-use-ops.stderr
new file mode 100644
index 00000000000..f444ef09075
--- /dev/null
+++ b/src/test/ui/lint/must-use-ops.stderr
@@ -0,0 +1,132 @@
+warning: unused comparison which must be used
+  --> $DIR/must-use-ops.rs:23:5
+   |
+LL |     val == 1;
+   |     ^^^^^^^^
+   |
+note: lint level defined here
+  --> $DIR/must-use-ops.rs:16:9
+   |
+LL | #![warn(unused_must_use)]
+   |         ^^^^^^^^^^^^^^^
+
+warning: unused comparison which must be used
+  --> $DIR/must-use-ops.rs:24:5
+   |
+LL |     val < 1;
+   |     ^^^^^^^
+
+warning: unused comparison which must be used
+  --> $DIR/must-use-ops.rs:25:5
+   |
+LL |     val <= 1;
+   |     ^^^^^^^^
+
+warning: unused comparison which must be used
+  --> $DIR/must-use-ops.rs:26:5
+   |
+LL |     val != 1;
+   |     ^^^^^^^^
+
+warning: unused comparison which must be used
+  --> $DIR/must-use-ops.rs:27:5
+   |
+LL |     val >= 1;
+   |     ^^^^^^^^
+
+warning: unused comparison which must be used
+  --> $DIR/must-use-ops.rs:28:5
+   |
+LL |     val > 1;
+   |     ^^^^^^^
+
+warning: unused arithmetic operation which must be used
+  --> $DIR/must-use-ops.rs:31:5
+   |
+LL |     val + 2;
+   |     ^^^^^^^
+
+warning: unused arithmetic operation which must be used
+  --> $DIR/must-use-ops.rs:32:5
+   |
+LL |     val - 2;
+   |     ^^^^^^^
+
+warning: unused arithmetic operation which must be used
+  --> $DIR/must-use-ops.rs:33:5
+   |
+LL |     val / 2;
+   |     ^^^^^^^
+
+warning: unused arithmetic operation which must be used
+  --> $DIR/must-use-ops.rs:34:5
+   |
+LL |     val * 2;
+   |     ^^^^^^^
+
+warning: unused arithmetic operation which must be used
+  --> $DIR/must-use-ops.rs:35:5
+   |
+LL |     val % 2;
+   |     ^^^^^^^
+
+warning: unused logical operation which must be used
+  --> $DIR/must-use-ops.rs:38:5
+   |
+LL |     true && true;
+   |     ^^^^^^^^^^^^
+
+warning: unused logical operation which must be used
+  --> $DIR/must-use-ops.rs:39:5
+   |
+LL |     false || true;
+   |     ^^^^^^^^^^^^^
+
+warning: unused bitwise operation which must be used
+  --> $DIR/must-use-ops.rs:42:5
+   |
+LL |     5 ^ val;
+   |     ^^^^^^^
+
+warning: unused bitwise operation which must be used
+  --> $DIR/must-use-ops.rs:43:5
+   |
+LL |     5 & val;
+   |     ^^^^^^^
+
+warning: unused bitwise operation which must be used
+  --> $DIR/must-use-ops.rs:44:5
+   |
+LL |     5 | val;
+   |     ^^^^^^^
+
+warning: unused bitwise operation which must be used
+  --> $DIR/must-use-ops.rs:45:5
+   |
+LL |     5 << val;
+   |     ^^^^^^^^
+
+warning: unused bitwise operation which must be used
+  --> $DIR/must-use-ops.rs:46:5
+   |
+LL |     5 >> val;
+   |     ^^^^^^^^
+
+warning: unused unary operation which must be used
+  --> $DIR/must-use-ops.rs:49:5
+   |
+LL |     !val;
+   |     ^^^^
+
+warning: unused unary operation which must be used
+  --> $DIR/must-use-ops.rs:50:5
+   |
+LL |     -val;
+   |     ^^^^
+
+warning: unused unary operation which must be used
+  --> $DIR/must-use-ops.rs:51:5
+   |
+LL |     *val_pointer;
+   |     ^^^^^^^^^^^^
+