Add reference annotations for unions

tests/ui/borrowck/borrowck-union-borrow-nested.rs

@@ -29,3 +29,5 @@ fn main() {
 
 trait Fake { fn use_mut(&mut self) { } fn use_ref(&self) { }  }
 impl<T> Fake for T { }
+
+//@ reference: items.union.ref.borrow

tests/ui/borrowck/borrowck-union-borrow.rs

@@ -94,3 +94,5 @@ fn main() {
         }
     }
 }
+
+//@ reference: items.union.ref.borrow

tests/ui/consts/const-eval/union-const-eval-field.rs

@@ -37,3 +37,6 @@ fn main() {
     assert_eq!(read_field2(), 1.0);
     assert_eq!(read_field3(), unsafe { UNION.field3 });
 }
+
+//@ reference: items.union.fields.read
+//@ reference: items.union.fields.validity

tests/ui/consts/const-eval/union-ub.rs

@@ -40,3 +40,6 @@ const UNINIT_BOOL: bool = unsafe { DummyUnion { unit: () }.bool };
 const BAD_UNION: Foo = unsafe { Bar { u8: 42 }.foo };
 
 fn main() {}
+
+//@ reference: items.union.fields.intro
+//@ reference: items.union.fields.validity

tests/ui/macros/stringify.rs

@@ -1001,3 +1001,5 @@ fn test_punct() {
     p!([ ,; ;, ** @@ $+$ >< <> ?? +== ], ",; ;, ** @@ $+$ >< <> ?? +==");
     p!([ :#!@|$=&*,+;*~? ], ":#!@|$=&*,+;*~?");
 }
+
+//@ reference: items.union.fieldless

tests/ui/nll/issue-45157.rs

@@ -29,3 +29,5 @@ fn main() {
         println!("{} {}", mref, nref)
     }
 }
+
+//@ reference: items.union.ref.borrow

tests/ui/nll/issue-57100.rs

@@ -65,3 +65,5 @@ fn first_union() {
 }
 
 fn main() {}
+
+//@ reference: items.union.ref.borrow

tests/ui/parser/recover/recover-field-semi.rs

@@ -16,3 +16,5 @@ enum Baz {
 fn main() {
     let _ = Foo { foo: "" }; //~ ERROR mismatched types
 }
+
+//@ reference: items.union.syntax

tests/ui/privacy/union-field-privacy-1.rs

@@ -15,3 +15,5 @@ fn main() { unsafe {
     let m::U { b } = u; // OK
     let m::U { c } = u; //~ ERROR field `c` of union `U` is private
 }}
+
+//@ reference: items.union.ref.use

tests/ui/privacy/union-field-privacy-2.rs

@@ -13,3 +13,5 @@ fn main() {
     let b = u.b; // OK
     let c = u.c; //~ ERROR field `c` of union `U` is private
 }
+
+//@ reference: items.union.ref.use

tests/ui/union/union-basic.rs

@@ -58,3 +58,6 @@ fn main() {
     local();
     xcrate();
 }
+
+//@ reference: items.union.common-storage
+//@ reference: items.union.init.result

tests/ui/union/union-inherent-method.rs

@@ -1,5 +1,4 @@
 //@ run-pass
-//@ reference: items.impl.inherent.allowed-items
 
 union U {
     a: u8,
@@ -13,3 +12,6 @@ fn main() {
     let u = U { a: 10 };
     assert_eq!(u.method(), 10);
 }
+
+//@ reference: items.impl.inherent.allowed-items
+//@ reference: items.union.ref.use

tests/ui/union/union-modification.rs

@@ -32,3 +32,5 @@ pub fn main() {
     assert_eq!(unsafe { foo_holder.inner_foo.bar }, 4);
     drop(foo_holder);
 }
+
+//@ reference: items.union.fields.write-safety

tests/ui/union/union-nodrop.rs

@@ -64,3 +64,5 @@ fn main() {
     assert!(needs_drop::<ActuallyDrop<u8>>());
     assert!(needs_drop::<ActuallyDrop<Box<u8>>>());
 }
+
+//@ reference: items.union.drop

tests/ui/union/union-repr-c.rs

@@ -16,3 +16,5 @@ extern "C" {
 }
 
 fn main() {}
+
+//@ reference: type.union.layout

tests/ui/union/union-transmute.rs

@@ -1,6 +1,4 @@
 //@ run-pass
-//@ reference: items.union.common-storage
-//@ reference: type.union.access
 
 union U {
     a: (u8, u8),
@@ -25,3 +23,7 @@ fn main() {
         assert_eq!(w.a, 0b1_11111111_00000000000000000000000);
     }
 }
+
+//@ reference: items.union.common-storage
+//@ reference: items.union.fields.intro
+//@ reference: type.union.access

tests/ui/union/union.rs

@@ -47,3 +47,5 @@ pub fn main() {
     }
     let Foo { bar: _ } = foo;
 }
+
+//@ reference: items.union.pattern.safety