1 files changed, 56 insertions, 0 deletions
diff --git a/src/tools/clippy/tests/ui/double_parens.rs b/src/tools/clippy/tests/ui/double_parens.rs
new file mode 100644
index 000000000..ff1dc76ab
--- /dev/null
+++ b/src/tools/clippy/tests/ui/double_parens.rs
@@ -0,0 +1,56 @@
+#![warn(clippy::double_parens)]
+#![allow(dead_code, clippy::eq_op)]
+#![feature(custom_inner_attributes)]
+#![rustfmt::skip]
+
+fn dummy_fn<T>(_: T) {}
+
+struct DummyStruct;
+
+impl DummyStruct {
+    fn dummy_method<T>(self, _: T) {}
+}
+
+fn simple_double_parens() -> i32 {
+    ((0))
+}
+
+fn fn_double_parens() {
+    dummy_fn((0));
+}
+
+fn method_double_parens(x: DummyStruct) {
+    x.dummy_method((0));
+}
+
+fn tuple_double_parens() -> (i32, i32) {
+    ((1, 2))
+}
+
+fn unit_double_parens() {
+    (())
+}
+
+fn fn_tuple_ok() {
+    dummy_fn((1, 2));
+}
+
+fn method_tuple_ok(x: DummyStruct) {
+    x.dummy_method((1, 2));
+}
+
+fn fn_unit_ok() {
+    dummy_fn(());
+}
+
+fn method_unit_ok(x: DummyStruct) {
+    x.dummy_method(());
+}
+
+// Issue #3206
+fn inside_macro() {
+    assert_eq!((1, 2), (1, 2), "Error");
+    assert_eq!(((1, 2)), (1, 2), "Error");
+}
+
+fn main() {}