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-rw-r--r--src/test/ui/regions/regions-early-bound-trait-param.rs132
1 files changed, 132 insertions, 0 deletions
diff --git a/src/test/ui/regions/regions-early-bound-trait-param.rs b/src/test/ui/regions/regions-early-bound-trait-param.rs
new file mode 100644
index 000000000..a28bd14ba
--- /dev/null
+++ b/src/test/ui/regions/regions-early-bound-trait-param.rs
@@ -0,0 +1,132 @@
+// run-pass
+// Tests that you can use an early-bound lifetime parameter as
+// on of the generic parameters in a trait.
+
+trait Trait<'a> {
+ fn long(&'a self) -> isize;
+ fn short<'b>(&'b self) -> isize;
+}
+
+fn poly_invoke<'c, T: Trait<'c>>(x: &'c T) -> (isize, isize) {
+ let l = x.long();
+ let s = x.short();
+ (l,s)
+}
+
+fn object_invoke1<'d>(x: &'d dyn Trait<'d>) -> (isize, isize) {
+ let l = x.long();
+ let s = x.short();
+ (l,s)
+}
+
+struct Struct1<'e> {
+ f: &'e (dyn Trait<'e>+'e)
+}
+
+fn field_invoke1<'f, 'g>(x: &'g Struct1<'f>) -> (isize,isize) {
+ let l = x.f.long();
+ let s = x.f.short();
+ (l,s)
+}
+
+struct Struct2<'h, 'i:'h> {
+ f: &'h (dyn Trait<'i>+'h)
+}
+
+fn object_invoke2<'j, 'k>(x: &'k dyn Trait<'j>) -> isize {
+ x.short()
+}
+
+fn field_invoke2<'l, 'm, 'n>(x: &'n Struct2<'l,'m>) -> isize {
+ x.f.short()
+}
+
+trait MakerTrait {
+ fn mk() -> Self;
+}
+
+fn make_val<T:MakerTrait>() -> T {
+ MakerTrait::mk()
+}
+
+trait RefMakerTrait<'q> {
+ fn mk(_: Self) -> &'q Self;
+}
+
+fn make_ref<'r, T:RefMakerTrait<'r>>(t:T) -> &'r T {
+ RefMakerTrait::mk(t)
+}
+
+impl<'s> Trait<'s> for (isize,isize) {
+ fn long(&'s self) -> isize {
+ let &(x,_) = self;
+ x
+ }
+ fn short<'b>(&'b self) -> isize {
+ let &(_,y) = self;
+ y
+ }
+}
+
+impl<'t> MakerTrait for Box<dyn Trait<'t>+'static> {
+ fn mk() -> Box<dyn Trait<'t>+'static> {
+ let tup: Box<(isize, isize)> = Box::new((4,5));
+ tup as Box<dyn Trait>
+ }
+}
+
+enum List<'l> {
+ Cons(isize, &'l List<'l>),
+ Null
+}
+
+impl<'l> List<'l> {
+ fn car<'m>(&'m self) -> isize {
+ match self {
+ &List::Cons(car, _) => car,
+ &List::Null => panic!(),
+ }
+ }
+ fn cdr<'n>(&'n self) -> &'l List<'l> {
+ match self {
+ &List::Cons(_, cdr) => cdr,
+ &List::Null => panic!(),
+ }
+ }
+}
+
+impl<'t> RefMakerTrait<'t> for List<'t> {
+ fn mk(l:List<'t>) -> &'t List<'t> {
+ l.cdr()
+ }
+}
+
+pub fn main() {
+ let t = (2,3);
+ let o = &t as &dyn Trait;
+ let s1 = Struct1 { f: o };
+ let s2 = Struct2 { f: o };
+ assert_eq!(poly_invoke(&t), (2,3));
+ assert_eq!(object_invoke1(&t), (2,3));
+ assert_eq!(field_invoke1(&s1), (2,3));
+ assert_eq!(object_invoke2(&t), 3);
+ assert_eq!(field_invoke2(&s2), 3);
+
+ let m : Box<dyn Trait> = make_val();
+ // assert_eq!(object_invoke1(&*m), (4,5));
+ // ~~~~~~~~~~~~~~~~~~~
+ // this call yields a compilation error; see ui/span/dropck-object-cycle.rs
+ // for details.
+ assert_eq!(object_invoke2(&*m), 5);
+
+ // The RefMakerTrait above is pretty strange (i.e., it is strange
+ // to consume a value of type T and return a &T). Easiest thing
+ // that came to my mind: consume a cell of a linked list and
+ // return a reference to the list it points to.
+ let l0 = List::Null;
+ let l1 = List::Cons(1, &l0);
+ let l2 = List::Cons(2, &l1);
+ let rl1 = &l1;
+ let r = make_ref(l2);
+ assert_eq!(rl1.car(), r.car());
+}