From 109cc1de9201e0523a24de1ad543f9baa23b57dc Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Sun, 7 Aug 2022 16:52:46 -0700
Subject: [PATCH] Add tuple trait tests

---
 src/test/ui/explore-issue-38412.stderr |  6 +--
 src/test/ui/tuple/builtin-fail.rs      | 19 +++++++++
 src/test/ui/tuple/builtin-fail.stderr  | 55 ++++++++++++++++++++++++++
 src/test/ui/tuple/builtin.rs           | 20 ++++++++++
 4 files changed, 97 insertions(+), 3 deletions(-)
 create mode 100644 src/test/ui/tuple/builtin-fail.rs
 create mode 100644 src/test/ui/tuple/builtin-fail.stderr
 create mode 100644 src/test/ui/tuple/builtin.rs

diff --git a/src/test/ui/explore-issue-38412.stderr b/src/test/ui/explore-issue-38412.stderr
index e3f82137ab3b2..08dadb4db851a 100644
--- a/src/test/ui/explore-issue-38412.stderr
+++ b/src/test/ui/explore-issue-38412.stderr
@@ -43,19 +43,19 @@ LL |     t.2;
    = note: see issue #38412 <https://github.com/rust-lang/rust/issues/38412> for more information
    = help: add `#![feature(unstable_undeclared)]` to the crate attributes to enable
 
-error[E0616]: field `3` of struct `Tuple` is private
+error[E0616]: field `3` of struct `pub_and_stability::Tuple` is private
   --> $DIR/explore-issue-38412.rs:36:7
    |
 LL |     t.3;
    |       ^ private field
 
-error[E0616]: field `4` of struct `Tuple` is private
+error[E0616]: field `4` of struct `pub_and_stability::Tuple` is private
   --> $DIR/explore-issue-38412.rs:37:7
    |
 LL |     t.4;
    |       ^ private field
 
-error[E0616]: field `5` of struct `Tuple` is private
+error[E0616]: field `5` of struct `pub_and_stability::Tuple` is private
   --> $DIR/explore-issue-38412.rs:38:7
    |
 LL |     t.5;
diff --git a/src/test/ui/tuple/builtin-fail.rs b/src/test/ui/tuple/builtin-fail.rs
new file mode 100644
index 0000000000000..31208096151dc
--- /dev/null
+++ b/src/test/ui/tuple/builtin-fail.rs
@@ -0,0 +1,19 @@
+#![feature(tuple_trait)]
+
+fn assert_is_tuple<T: std::marker::Tuple + ?Sized>() {}
+
+struct TupleStruct(i32, i32);
+
+fn from_param_env<T>() {
+    assert_is_tuple::<T>();
+    //~^ ERROR `T` is not a tuple
+}
+
+fn main() {
+    assert_is_tuple::<i32>();
+    //~^ ERROR `i32` is not a tuple
+    assert_is_tuple::<(i32)>();
+    //~^ ERROR `i32` is not a tuple
+    assert_is_tuple::<TupleStruct>();
+    //~^ ERROR `TupleStruct` is not a tuple
+}
diff --git a/src/test/ui/tuple/builtin-fail.stderr b/src/test/ui/tuple/builtin-fail.stderr
new file mode 100644
index 0000000000000..e3e29a73fdc01
--- /dev/null
+++ b/src/test/ui/tuple/builtin-fail.stderr
@@ -0,0 +1,55 @@
+error[E0277]: `T` is not a tuple
+  --> $DIR/builtin-fail.rs:8:23
+   |
+LL |     assert_is_tuple::<T>();
+   |                       ^ the trait `Tuple` is not implemented for `T`
+   |
+note: required by a bound in `assert_is_tuple`
+  --> $DIR/builtin-fail.rs:3:23
+   |
+LL | fn assert_is_tuple<T: std::marker::Tuple + ?Sized>() {}
+   |                       ^^^^^^^^^^^^^^^^^^ required by this bound in `assert_is_tuple`
+help: consider restricting type parameter `T`
+   |
+LL | fn from_param_env<T: std::marker::Tuple>() {
+   |                    ++++++++++++++++++++
+
+error[E0277]: `i32` is not a tuple
+  --> $DIR/builtin-fail.rs:13:23
+   |
+LL |     assert_is_tuple::<i32>();
+   |                       ^^^ the trait `Tuple` is not implemented for `i32`
+   |
+note: required by a bound in `assert_is_tuple`
+  --> $DIR/builtin-fail.rs:3:23
+   |
+LL | fn assert_is_tuple<T: std::marker::Tuple + ?Sized>() {}
+   |                       ^^^^^^^^^^^^^^^^^^ required by this bound in `assert_is_tuple`
+
+error[E0277]: `i32` is not a tuple
+  --> $DIR/builtin-fail.rs:15:24
+   |
+LL |     assert_is_tuple::<(i32)>();
+   |                        ^^^ the trait `Tuple` is not implemented for `i32`
+   |
+note: required by a bound in `assert_is_tuple`
+  --> $DIR/builtin-fail.rs:3:23
+   |
+LL | fn assert_is_tuple<T: std::marker::Tuple + ?Sized>() {}
+   |                       ^^^^^^^^^^^^^^^^^^ required by this bound in `assert_is_tuple`
+
+error[E0277]: `TupleStruct` is not a tuple
+  --> $DIR/builtin-fail.rs:17:23
+   |
+LL |     assert_is_tuple::<TupleStruct>();
+   |                       ^^^^^^^^^^^ the trait `Tuple` is not implemented for `TupleStruct`
+   |
+note: required by a bound in `assert_is_tuple`
+  --> $DIR/builtin-fail.rs:3:23
+   |
+LL | fn assert_is_tuple<T: std::marker::Tuple + ?Sized>() {}
+   |                       ^^^^^^^^^^^^^^^^^^ required by this bound in `assert_is_tuple`
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/tuple/builtin.rs b/src/test/ui/tuple/builtin.rs
new file mode 100644
index 0000000000000..d87ce526357e3
--- /dev/null
+++ b/src/test/ui/tuple/builtin.rs
@@ -0,0 +1,20 @@
+// check-pass
+
+#![feature(tuple_trait)]
+
+fn assert_is_tuple<T: std::marker::Tuple + ?Sized>() {}
+
+struct Unsized([u8]);
+
+fn from_param_env<T: std::marker::Tuple + ?Sized>() {
+    assert_is_tuple::<T>();
+}
+
+fn main() {
+    assert_is_tuple::<()>();
+    assert_is_tuple::<(i32,)>();
+    assert_is_tuple::<(Unsized,)>();
+    from_param_env::<()>();
+    from_param_env::<(i32,)>();
+    from_param_env::<(Unsized,)>();
+}