1 files changed, 81 insertions, 0 deletions
diff --git a/tests/ui/lint/lint-unnecessary-parens.rs b/tests/ui/lint/lint-unnecessary-parens.rs
new file mode 100644
index 000000000..4fd9cabb3
--- /dev/null
+++ b/tests/ui/lint/lint-unnecessary-parens.rs
@@ -0,0 +1,81 @@
+// run-rustfix
+
+#![deny(unused_parens)]
+#![allow(while_true)] // for rustfix
+
+#[derive(Eq, PartialEq)]
+struct X { y: bool }
+impl X {
+    fn foo(&self, conjunct: bool) -> bool { self.y && conjunct }
+}
+
+fn foo() -> isize {
+    return (1); //~ ERROR unnecessary parentheses around `return` value
+}
+fn bar(y: bool) -> X {
+    return (X { y }); //~ ERROR unnecessary parentheses around `return` value
+}
+
+pub fn unused_parens_around_return_type() -> (u32) { //~ ERROR unnecessary parentheses around type
+    panic!()
+}
+
+pub fn unused_parens_around_block_return() -> u32 {
+    let _foo = {
+        (5) //~ ERROR unnecessary parentheses around block return value
+    };
+    (5) //~ ERROR unnecessary parentheses around block return value
+}
+
+pub trait Trait {
+    fn test(&self);
+}
+
+pub fn passes_unused_parens_lint() -> &'static (dyn Trait) {
+    panic!()
+}
+
+macro_rules! baz {
+    ($($foo:expr),+) => {
+        ($($foo),*)
+    }
+}
+
+pub const CONST_ITEM: usize = (10); //~ ERROR unnecessary parentheses around assigned value
+pub static STATIC_ITEM: usize = (10); //~ ERROR unnecessary parentheses around assigned value
+
+fn main() {
+    foo();
+    bar((true)); //~ ERROR unnecessary parentheses around function argument
+
+    if (true) {} //~ ERROR unnecessary parentheses around `if` condition
+    while (true) {} //~ ERROR unnecessary parentheses around `while` condition
+    match (true) { //~ ERROR unnecessary parentheses around `match` scrutinee expression
+        _ => {}
+    }
+    if let 1 = (1) {} //~ ERROR unnecessary parentheses around `let` scrutinee expression
+    while let 1 = (2) {} //~ ERROR unnecessary parentheses around `let` scrutinee expression
+    let v = X { y: false };
+    // struct lits needs parens, so these shouldn't warn.
+    if (v == X { y: true }) {}
+    if (X { y: true } == v) {}
+    if (X { y: false }.y) {}
+    // this shouldn't warn, because the parens are necessary to disambiguate let chains
+    if let true = (true && false) {}
+
+    while (X { y: false }.foo(true)) {}
+    while (true | X { y: false }.y) {}
+
+    match (X { y: false }) {
+        _ => {}
+    }
+
+    X { y: false }.foo((true)); //~ ERROR unnecessary parentheses around method argument
+
+    let mut _a = (0); //~ ERROR unnecessary parentheses around assigned value
+    _a = (0); //~ ERROR unnecessary parentheses around assigned value
+    _a += (1); //~ ERROR unnecessary parentheses around assigned value
+
+    let _a = baz!(3, 4);
+    let _b = baz!(3);
+}