Rollup merge of #143210 - Kivooeo:tf19, r=tgross35

`tests/ui`: A New Order [19/N]

> [!NOTE]
>
> Intermediate commits are intended to help review, but will be squashed prior to merge.

Some `tests/ui/` housekeeping, to trim down number of tests directly under `tests/ui/`. Part of rust-lang/rust#133895.

r? `@tgross35`

26 files changed, 265 insertions, 222 deletions

diff --git a/tests/ui/closures/basic-closure-syntax.rs b/tests/ui/closures/basic-closure-syntax.rs
new file mode 100644
index 00000000000..1d968f8cf4a
--- /dev/null
+++ b/tests/ui/closures/basic-closure-syntax.rs
@@ -0,0 +1,35 @@
+//! Test basic closure syntax and usage with generic functions.
+//!
+//! This test checks that closure syntax works correctly for:
+//! - Closures with parameters and return values
+//! - Closures without parameters (both expression and block forms)
+//! - Integration with generic functions and FnOnce trait bounds
+
+//@ run-pass
+
+fn f<F>(i: isize, f: F) -> isize
+where
+    F: FnOnce(isize) -> isize,
+{
+    f(i)
+}
+
+fn g<G>(_g: G)
+where
+    G: FnOnce(),
+{
+}
+
+pub fn main() {
+    // Closure with parameter that returns the same value
+    assert_eq!(f(10, |a| a), 10);
+
+    // Closure without parameters - expression form
+    g(|| ());
+
+    // Test closure reuse in generic context
+    assert_eq!(f(10, |a| a), 10);
+
+    // Closure without parameters - block form
+    g(|| {});
+}
diff --git a/tests/ui/generics/newtype-with-generics.rs b/tests/ui/generics/newtype-with-generics.rs
new file mode 100644
index 00000000000..c5e200e4bc4
--- /dev/null
+++ b/tests/ui/generics/newtype-with-generics.rs
@@ -0,0 +1,32 @@
+//! Test newtype pattern with generic parameters.
+
+//@ run-pass
+
+#[derive(Clone)]
+struct MyVec<T>(Vec<T>);
+
+fn extract_inner_vec<T: Clone>(wrapper: MyVec<T>) -> Vec<T> {
+    let MyVec(inner_vec) = wrapper;
+    inner_vec.clone()
+}
+
+fn get_first_element<T>(wrapper: MyVec<T>) -> T {
+    let MyVec(inner_vec) = wrapper;
+    inner_vec.into_iter().next().unwrap()
+}
+
+pub fn main() {
+    let my_vec = MyVec(vec![1, 2, 3]);
+    let cloned_vec = my_vec.clone();
+
+    // Test extracting inner vector
+    let extracted = extract_inner_vec(cloned_vec);
+    assert_eq!(extracted[1], 2);
+
+    // Test getting first element
+    assert_eq!(get_first_element(my_vec.clone()), 1);
+
+    // Test direct destructuring
+    let MyVec(inner) = my_vec;
+    assert_eq!(inner[2], 3);
+}
diff --git a/tests/ui/new-impl-syntax.rs b/tests/ui/impl-trait/basic-trait-impl.rs
index 124d604e6a8..2706c9c1798 100644
--- a/tests/ui/new-impl-syntax.rs
+++ b/tests/ui/impl-trait/basic-trait-impl.rs
@@ -1,10 +1,12 @@
+//! Test basic trait implementation syntax for both simple and generic types.
+
 //@ run-pass
 
 use std::fmt;
 
 struct Thingy {
     x: isize,
-    y: isize
+    y: isize,
 }
 
 impl fmt::Debug for Thingy {
@@ -14,10 +16,10 @@ impl fmt::Debug for Thingy {
 }
 
 struct PolymorphicThingy<T> {
-    x: T
+    x: T,
 }
 
-impl<T:fmt::Debug> fmt::Debug for PolymorphicThingy<T> {
+impl<T: fmt::Debug> fmt::Debug for PolymorphicThingy<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "{:?}", self.x)
     }
diff --git a/tests/ui/new-import-syntax.rs b/tests/ui/new-import-syntax.rs
deleted file mode 100644
index 547900fab61..00000000000
--- a/tests/ui/new-import-syntax.rs
+++ /dev/null
@@ -1,5 +0,0 @@
-//@ run-pass
-
-pub fn main() {
-    println!("Hello world!");
-}
diff --git a/tests/ui/new-style-constants.rs b/tests/ui/new-style-constants.rs
deleted file mode 100644
index e33a2da3878..00000000000
--- a/tests/ui/new-style-constants.rs
+++ /dev/null
@@ -1,7 +0,0 @@
-//@ run-pass
-
-static FOO: isize = 3;
-
-pub fn main() {
-    println!("{}", FOO);
-}
diff --git a/tests/ui/newlambdas.rs b/tests/ui/newlambdas.rs
deleted file mode 100644
index 75e851fb73a..00000000000
--- a/tests/ui/newlambdas.rs
+++ /dev/null
@@ -1,14 +0,0 @@
-//@ run-pass
-// Tests for the new |args| expr lambda syntax
-
-
-fn f<F>(i: isize, f: F) -> isize where F: FnOnce(isize) -> isize { f(i) }
-
-fn g<G>(_g: G) where G: FnOnce() { }
-
-pub fn main() {
-    assert_eq!(f(10, |a| a), 10);
-    g(||());
-    assert_eq!(f(10, |a| a), 10);
-    g(||{});
-}
diff --git a/tests/ui/newtype-polymorphic.rs b/tests/ui/newtype-polymorphic.rs
deleted file mode 100644
index 146d49fdf68..00000000000
--- a/tests/ui/newtype-polymorphic.rs
+++ /dev/null
@@ -1,27 +0,0 @@
-//@ run-pass
-
-#![allow(non_camel_case_types)]
-
-
-#[derive(Clone)]
-struct myvec<X>(Vec<X> );
-
-fn myvec_deref<X:Clone>(mv: myvec<X>) -> Vec<X> {
-    let myvec(v) = mv;
-    return v.clone();
-}
-
-fn myvec_elt<X>(mv: myvec<X>) -> X {
-    let myvec(v) = mv;
-    return v.into_iter().next().unwrap();
-}
-
-pub fn main() {
-    let mv = myvec(vec![1, 2, 3]);
-    let mv_clone = mv.clone();
-    let mv_clone = myvec_deref(mv_clone);
-    assert_eq!(mv_clone[1], 2);
-    assert_eq!(myvec_elt(mv.clone()), 1);
-    let myvec(v) = mv;
-    assert_eq!(v[2], 3);
-}
diff --git a/tests/ui/newtype.rs b/tests/ui/newtype.rs
deleted file mode 100644
index 8a07c67eb4f..00000000000
--- a/tests/ui/newtype.rs
+++ /dev/null
@@ -1,23 +0,0 @@
-//@ run-pass
-
-#![allow(non_camel_case_types)]
-#[derive(Copy, Clone)]
-struct mytype(Mytype);
-
-#[derive(Copy, Clone)]
-struct Mytype {
-    compute: fn(mytype) -> isize,
-    val: isize,
-}
-
-fn compute(i: mytype) -> isize {
-    let mytype(m) = i;
-    return m.val + 20;
-}
-
-pub fn main() {
-    let myval = mytype(Mytype{compute: compute, val: 30});
-    println!("{}", compute(myval));
-    let mytype(m) = myval;
-    assert_eq!((m.compute)(myval), 50);
-}
diff --git a/tests/ui/no_send-enum.rs b/tests/ui/no_send-enum.rs
deleted file mode 100644
index bd560649b99..00000000000
--- a/tests/ui/no_send-enum.rs
+++ /dev/null
@@ -1,18 +0,0 @@
-#![feature(negative_impls)]
-
-use std::marker::Send;
-
-struct NoSend;
-impl !Send for NoSend {}
-
-enum Foo {
-    A(NoSend)
-}
-
-fn bar<T: Send>(_: T) {}
-
-fn main() {
-    let x = Foo::A(NoSend);
-    bar(x);
-    //~^ ERROR `NoSend` cannot be sent between threads safely
-}
diff --git a/tests/ui/no_send-enum.stderr b/tests/ui/no_send-enum.stderr
deleted file mode 100644
index 3b66c7db545..00000000000
--- a/tests/ui/no_send-enum.stderr
+++ /dev/null
@@ -1,23 +0,0 @@
-error[E0277]: `NoSend` cannot be sent between threads safely
-  --> $DIR/no_send-enum.rs:16:9
-   |
-LL |     bar(x);
-   |     --- ^ `NoSend` cannot be sent between threads safely
-   |     |
-   |     required by a bound introduced by this call
-   |
-   = help: within `Foo`, the trait `Send` is not implemented for `NoSend`
-note: required because it appears within the type `Foo`
-  --> $DIR/no_send-enum.rs:8:6
-   |
-LL | enum Foo {
-   |      ^^^
-note: required by a bound in `bar`
-  --> $DIR/no_send-enum.rs:12:11
-   |
-LL | fn bar<T: Send>(_: T) {}
-   |           ^^^^ required by this bound in `bar`
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/no_send-rc.rs b/tests/ui/no_send-rc.rs
deleted file mode 100644
index f31db15ef2e..00000000000
--- a/tests/ui/no_send-rc.rs
+++ /dev/null
@@ -1,9 +0,0 @@
-use std::rc::Rc;
-
-fn bar<T: Send>(_: T) {}
-
-fn main() {
-    let x = Rc::new(5);
-    bar(x);
-    //~^ ERROR `Rc<{integer}>` cannot be sent between threads safely
-}
diff --git a/tests/ui/no_send-rc.stderr b/tests/ui/no_send-rc.stderr
deleted file mode 100644
index 1430a7a29ea..00000000000
--- a/tests/ui/no_send-rc.stderr
+++ /dev/null
@@ -1,22 +0,0 @@
-error[E0277]: `Rc<{integer}>` cannot be sent between threads safely
-  --> $DIR/no_send-rc.rs:7:9
-   |
-LL |     bar(x);
-   |     --- ^ `Rc<{integer}>` cannot be sent between threads safely
-   |     |
-   |     required by a bound introduced by this call
-   |
-   = help: the trait `Send` is not implemented for `Rc<{integer}>`
-note: required by a bound in `bar`
-  --> $DIR/no_send-rc.rs:3:11
-   |
-LL | fn bar<T: Send>(_: T) {}
-   |           ^^^^ required by this bound in `bar`
-help: consider dereferencing here
-   |
-LL |     bar(*x);
-   |         +
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/no_share-enum.rs b/tests/ui/no_share-enum.rs
deleted file mode 100644
index 44bf1913e7a..00000000000
--- a/tests/ui/no_share-enum.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-#![feature(negative_impls)]
-
-use std::marker::Sync;
-
-struct NoSync;
-impl !Sync for NoSync {}
-
-enum Foo { A(NoSync) }
-
-fn bar<T: Sync>(_: T) {}
-
-fn main() {
-    let x = Foo::A(NoSync);
-    bar(x);
-    //~^ ERROR `NoSync` cannot be shared between threads safely [E0277]
-}
diff --git a/tests/ui/no_share-enum.stderr b/tests/ui/no_share-enum.stderr
deleted file mode 100644
index 89939216d5b..00000000000
--- a/tests/ui/no_share-enum.stderr
+++ /dev/null
@@ -1,23 +0,0 @@
-error[E0277]: `NoSync` cannot be shared between threads safely
-  --> $DIR/no_share-enum.rs:14:9
-   |
-LL |     bar(x);
-   |     --- ^ `NoSync` cannot be shared between threads safely
-   |     |
-   |     required by a bound introduced by this call
-   |
-   = help: within `Foo`, the trait `Sync` is not implemented for `NoSync`
-note: required because it appears within the type `Foo`
-  --> $DIR/no_share-enum.rs:8:6
-   |
-LL | enum Foo { A(NoSync) }
-   |      ^^^
-note: required by a bound in `bar`
-  --> $DIR/no_share-enum.rs:10:11
-   |
-LL | fn bar<T: Sync>(_: T) {}
-   |           ^^^^ required by this bound in `bar`
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/no_share-struct.rs b/tests/ui/no_share-struct.rs
deleted file mode 100644
index 7d8a36a76f2..00000000000
--- a/tests/ui/no_share-struct.rs
+++ /dev/null
@@ -1,14 +0,0 @@
-#![feature(negative_impls)]
-
-use std::marker::Sync;
-
-struct Foo { a: isize }
-impl !Sync for Foo {}
-
-fn bar<T: Sync>(_: T) {}
-
-fn main() {
-    let x = Foo { a: 5 };
-    bar(x);
-    //~^ ERROR `Foo` cannot be shared between threads safely [E0277]
-}
diff --git a/tests/ui/no_share-struct.stderr b/tests/ui/no_share-struct.stderr
deleted file mode 100644
index 9c7a921b8d8..00000000000
--- a/tests/ui/no_share-struct.stderr
+++ /dev/null
@@ -1,18 +0,0 @@
-error[E0277]: `Foo` cannot be shared between threads safely
-  --> $DIR/no_share-struct.rs:12:9
-   |
-LL |     bar(x);
-   |     --- ^ `Foo` cannot be shared between threads safely
-   |     |
-   |     required by a bound introduced by this call
-   |
-   = help: the trait `Sync` is not implemented for `Foo`
-note: required by a bound in `bar`
-  --> $DIR/no_share-struct.rs:8:11
-   |
-LL | fn bar<T: Sync>(_: T) {}
-   |           ^^^^ required by this bound in `bar`
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/new-unicode-escapes.rs b/tests/ui/parser/unicode-escape-sequences.rs
index 867a50da081..8b084866f19 100644
--- a/tests/ui/new-unicode-escapes.rs
+++ b/tests/ui/parser/unicode-escape-sequences.rs
@@ -1,6 +1,12 @@
+//! Test ES6-style Unicode escape sequences in string literals.
+//!
+//! Regression test for RFC 446 implementation.
+//! See <https://github.com/rust-lang/rust/pull/19480>.
+
 //@ run-pass
 
 pub fn main() {
+    // Basic Unicode escape - snowman character
     let s = "\u{2603}";
     assert_eq!(s, "☃");
 
diff --git a/tests/ui/structs/basic-newtype-pattern.rs b/tests/ui/structs/basic-newtype-pattern.rs
new file mode 100644
index 00000000000..38ccd0ea8e0
--- /dev/null
+++ b/tests/ui/structs/basic-newtype-pattern.rs
@@ -0,0 +1,25 @@
+//! Test basic newtype pattern functionality.
+
+//@ run-pass
+
+#[derive(Copy, Clone)]
+struct Counter(CounterData);
+
+#[derive(Copy, Clone)]
+struct CounterData {
+    compute: fn(Counter) -> isize,
+    val: isize,
+}
+
+fn compute_value(counter: Counter) -> isize {
+    let Counter(data) = counter;
+    data.val + 20
+}
+
+pub fn main() {
+    let my_counter = Counter(CounterData { compute: compute_value, val: 30 });
+
+    // Test destructuring and function pointer call
+    let Counter(data) = my_counter;
+    assert_eq!((data.compute)(my_counter), 50);
+}
diff --git a/tests/ui/traits/enum-negative-send-impl.rs b/tests/ui/traits/enum-negative-send-impl.rs
new file mode 100644
index 00000000000..6bff42e9999
--- /dev/null
+++ b/tests/ui/traits/enum-negative-send-impl.rs
@@ -0,0 +1,22 @@
+//! Test that enums inherit Send/!Send properties from their variants.
+//!
+//! Uses the unstable `negative_impls` feature to explicitly opt-out of Send.
+
+#![feature(negative_impls)]
+
+use std::marker::Send;
+
+struct NoSend;
+impl !Send for NoSend {}
+
+enum Container {
+    WithNoSend(NoSend),
+}
+
+fn requires_send<T: Send>(_: T) {}
+
+fn main() {
+    let container = Container::WithNoSend(NoSend);
+    requires_send(container);
+    //~^ ERROR `NoSend` cannot be sent between threads safely
+}
diff --git a/tests/ui/traits/enum-negative-send-impl.stderr b/tests/ui/traits/enum-negative-send-impl.stderr
new file mode 100644
index 00000000000..1992becccf4
--- /dev/null
+++ b/tests/ui/traits/enum-negative-send-impl.stderr
@@ -0,0 +1,23 @@
+error[E0277]: `NoSend` cannot be sent between threads safely
+  --> $DIR/enum-negative-send-impl.rs:20:19
+   |
+LL |     requires_send(container);
+   |     ------------- ^^^^^^^^^ `NoSend` cannot be sent between threads safely
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = help: within `Container`, the trait `Send` is not implemented for `NoSend`
+note: required because it appears within the type `Container`
+  --> $DIR/enum-negative-send-impl.rs:12:6
+   |
+LL | enum Container {
+   |      ^^^^^^^^^
+note: required by a bound in `requires_send`
+  --> $DIR/enum-negative-send-impl.rs:16:21
+   |
+LL | fn requires_send<T: Send>(_: T) {}
+   |                     ^^^^ required by this bound in `requires_send`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/traits/enum-negative-sync-impl.rs b/tests/ui/traits/enum-negative-sync-impl.rs
new file mode 100644
index 00000000000..aa81a9fbbf9
--- /dev/null
+++ b/tests/ui/traits/enum-negative-sync-impl.rs
@@ -0,0 +1,22 @@
+//! Test that enums inherit Sync/!Sync properties from their variants.
+//!
+//! Uses the unstable `negative_impls` feature to explicitly opt-out of Sync.
+
+#![feature(negative_impls)]
+
+use std::marker::Sync;
+
+struct NoSync;
+impl !Sync for NoSync {}
+
+enum Container {
+    WithNoSync(NoSync),
+}
+
+fn requires_sync<T: Sync>(_: T) {}
+
+fn main() {
+    let container = Container::WithNoSync(NoSync);
+    requires_sync(container);
+    //~^ ERROR `NoSync` cannot be shared between threads safely [E0277]
+}
diff --git a/tests/ui/traits/enum-negative-sync-impl.stderr b/tests/ui/traits/enum-negative-sync-impl.stderr
new file mode 100644
index 00000000000..a97b7a36a7b
--- /dev/null
+++ b/tests/ui/traits/enum-negative-sync-impl.stderr
@@ -0,0 +1,23 @@
+error[E0277]: `NoSync` cannot be shared between threads safely
+  --> $DIR/enum-negative-sync-impl.rs:20:19
+   |
+LL |     requires_sync(container);
+   |     ------------- ^^^^^^^^^ `NoSync` cannot be shared between threads safely
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = help: within `Container`, the trait `Sync` is not implemented for `NoSync`
+note: required because it appears within the type `Container`
+  --> $DIR/enum-negative-sync-impl.rs:12:6
+   |
+LL | enum Container {
+   |      ^^^^^^^^^
+note: required by a bound in `requires_sync`
+  --> $DIR/enum-negative-sync-impl.rs:16:21
+   |
+LL | fn requires_sync<T: Sync>(_: T) {}
+   |                     ^^^^ required by this bound in `requires_sync`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/traits/rc-not-send.rs b/tests/ui/traits/rc-not-send.rs
new file mode 100644
index 00000000000..83084c6173a
--- /dev/null
+++ b/tests/ui/traits/rc-not-send.rs
@@ -0,0 +1,11 @@
+//! Test that `Rc<T>` does not implement `Send`.
+
+use std::rc::Rc;
+
+fn requires_send<T: Send>(_: T) {}
+
+fn main() {
+    let rc_value = Rc::new(5);
+    requires_send(rc_value);
+    //~^ ERROR `Rc<{integer}>` cannot be sent between threads safely
+}
diff --git a/tests/ui/traits/rc-not-send.stderr b/tests/ui/traits/rc-not-send.stderr
new file mode 100644
index 00000000000..d6171a39ad0
--- /dev/null
+++ b/tests/ui/traits/rc-not-send.stderr
@@ -0,0 +1,22 @@
+error[E0277]: `Rc<{integer}>` cannot be sent between threads safely
+  --> $DIR/rc-not-send.rs:9:19
+   |
+LL |     requires_send(rc_value);
+   |     ------------- ^^^^^^^^ `Rc<{integer}>` cannot be sent between threads safely
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = help: the trait `Send` is not implemented for `Rc<{integer}>`
+note: required by a bound in `requires_send`
+  --> $DIR/rc-not-send.rs:5:21
+   |
+LL | fn requires_send<T: Send>(_: T) {}
+   |                     ^^^^ required by this bound in `requires_send`
+help: consider dereferencing here
+   |
+LL |     requires_send(*rc_value);
+   |                   +
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/traits/struct-negative-sync-impl.rs b/tests/ui/traits/struct-negative-sync-impl.rs
new file mode 100644
index 00000000000..d32846276f6
--- /dev/null
+++ b/tests/ui/traits/struct-negative-sync-impl.rs
@@ -0,0 +1,21 @@
+//! Test negative Sync implementation on structs.
+//!
+//! Uses the unstable `negative_impls` feature to explicitly opt-out of Sync.
+
+#![feature(negative_impls)]
+
+use std::marker::Sync;
+
+struct NotSync {
+    value: isize,
+}
+
+impl !Sync for NotSync {}
+
+fn requires_sync<T: Sync>(_: T) {}
+
+fn main() {
+    let not_sync = NotSync { value: 5 };
+    requires_sync(not_sync);
+    //~^ ERROR `NotSync` cannot be shared between threads safely [E0277]
+}
diff --git a/tests/ui/traits/struct-negative-sync-impl.stderr b/tests/ui/traits/struct-negative-sync-impl.stderr
new file mode 100644
index 00000000000..c5fd13f42e5
--- /dev/null
+++ b/tests/ui/traits/struct-negative-sync-impl.stderr
@@ -0,0 +1,18 @@
+error[E0277]: `NotSync` cannot be shared between threads safely
+  --> $DIR/struct-negative-sync-impl.rs:19:19
+   |
+LL |     requires_sync(not_sync);
+   |     ------------- ^^^^^^^^ `NotSync` cannot be shared between threads safely
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = help: the trait `Sync` is not implemented for `NotSync`
+note: required by a bound in `requires_sync`
+  --> $DIR/struct-negative-sync-impl.rs:15:21
+   |
+LL | fn requires_sync<T: Sync>(_: T) {}
+   |                     ^^^^ required by this bound in `requires_sync`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0277`.