Merging upstream version 1.72.1+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

5 files changed, 262 insertions, 0 deletions

diff --git a/tests/ui/rfcs/rfc-1623-static/rfc1623-2.rs b/tests/ui/rfcs/rfc-1623-static/rfc1623-2.rs
new file mode 100644
index 000000000..c0e13a5f5
--- /dev/null
+++ b/tests/ui/rfcs/rfc-1623-static/rfc1623-2.rs
@@ -0,0 +1,99 @@
+#![allow(dead_code)]
+
+fn non_elidable<'a, 'b>(a: &'a u8, b: &'b u8) -> &'a u8 {
+    a
+}
+
+// The incorrect case without `for<'a>` is tested for in `rfc1623-2.rs`
+static NON_ELIDABLE_FN: &for<'a> fn(&'a u8, &'a u8) -> &'a u8 =
+    &(non_elidable as for<'a> fn(&'a u8, &'a u8) -> &'a u8);
+
+struct SomeStruct<'x, 'y, 'z: 'x> {
+    foo: &'x Foo<'z>,
+    bar: &'x Bar<'z>,
+    f: &'y dyn for<'a, 'b> Fn(&'a Foo<'b>) -> &'a Foo<'b>,
+}
+
+// Without this, the wf-check will fail early so we'll never see the
+// error in SOME_STRUCT's body.
+unsafe impl<'x, 'y, 'z: 'x> Sync for SomeStruct<'x, 'y, 'z> {}
+
+fn id<T>(t: T) -> T {
+    t
+}
+
+static SOME_STRUCT: &SomeStruct = &SomeStruct {
+    foo: &Foo { bools: &[false, true] },
+    bar: &Bar { bools: &[true, true] },
+    f: &id,
+    //~^ ERROR mismatched types
+    //~| ERROR mismatched types
+    //~| ERROR implementation of `FnOnce` is not general enough
+    //~| ERROR implementation of `FnOnce` is not general enough
+};
+
+// very simple test for a 'static static with default lifetime
+static STATIC_STR: &'static str = "&'static str";
+const CONST_STR: &'static str = "&'static str";
+
+// this should be the same as without default:
+static EXPLICIT_STATIC_STR: &'static str = "&'static str";
+const EXPLICIT_CONST_STR: &'static str = "&'static str";
+
+// a function that elides to an unbound lifetime for both in- and output
+fn id_u8_slice(arg: &[u8]) -> &[u8] {
+    arg
+}
+
+// one with a function, argument elided
+static STATIC_SIMPLE_FN: &'static fn(&[u8]) -> &[u8] = &(id_u8_slice as fn(&[u8]) -> &[u8]);
+const CONST_SIMPLE_FN: &'static fn(&[u8]) -> &[u8] = &(id_u8_slice as fn(&[u8]) -> &[u8]);
+
+// this should be the same as without elision
+static STATIC_NON_ELIDED_fN: &'static for<'a> fn(&'a [u8]) -> &'a [u8] =
+    &(id_u8_slice as for<'a> fn(&'a [u8]) -> &'a [u8]);
+const CONST_NON_ELIDED_fN: &'static for<'a> fn(&'a [u8]) -> &'a [u8] =
+    &(id_u8_slice as for<'a> fn(&'a [u8]) -> &'a [u8]);
+
+// another function that elides, each to a different unbound lifetime
+fn multi_args(a: &u8, b: &u8, c: &u8) {}
+
+static STATIC_MULTI_FN: &'static fn(&u8, &u8, &u8) = &(multi_args as fn(&u8, &u8, &u8));
+const CONST_MULTI_FN: &'static fn(&u8, &u8, &u8) = &(multi_args as fn(&u8, &u8, &u8));
+
+struct Foo<'a> {
+    bools: &'a [bool],
+}
+
+static STATIC_FOO: Foo<'static> = Foo { bools: &[true, false] };
+const CONST_FOO: Foo<'static> = Foo { bools: &[true, false] };
+
+type Bar<'a> = Foo<'a>;
+
+static STATIC_BAR: Bar<'static> = Bar { bools: &[true, false] };
+const CONST_BAR: Bar<'static> = Bar { bools: &[true, false] };
+
+type Baz<'a> = fn(&'a [u8]) -> Option<u8>;
+
+fn baz(e: &[u8]) -> Option<u8> {
+    e.first().map(|x| *x)
+}
+
+static STATIC_BAZ: &'static Baz<'static> = &(baz as Baz);
+const CONST_BAZ: &'static Baz<'static> = &(baz as Baz);
+
+static BYTES: &'static [u8] = &[1, 2, 3];
+
+fn main() {
+    let x = &[1u8, 2, 3];
+    let y = x;
+
+    // this works, so lifetime < `'static` is valid
+    assert_eq!(Some(1), STATIC_BAZ(y));
+    assert_eq!(Some(1), CONST_BAZ(y));
+
+    let y = &[1u8, 2, 3];
+
+    STATIC_BAZ(BYTES); // BYTES has static lifetime
+    CONST_BAZ(y); // interestingly this does not get reported
+}
diff --git a/tests/ui/rfcs/rfc-1623-static/rfc1623-2.stderr b/tests/ui/rfcs/rfc-1623-static/rfc1623-2.stderr
new file mode 100644
index 000000000..d183eaaa6
--- /dev/null
+++ b/tests/ui/rfcs/rfc-1623-static/rfc1623-2.stderr
@@ -0,0 +1,39 @@
+error[E0308]: mismatched types
+  --> $DIR/rfc1623-2.rs:28:8
+   |
+LL |     f: &id,
+   |        ^^^ one type is more general than the other
+   |
+   = note: expected trait `for<'a, 'b> Fn<(&'a Foo<'b>,)>`
+              found trait `Fn<(&Foo<'_>,)>`
+
+error[E0308]: mismatched types
+  --> $DIR/rfc1623-2.rs:28:8
+   |
+LL |     f: &id,
+   |        ^^^ one type is more general than the other
+   |
+   = note: expected trait `for<'a, 'b> Fn<(&'a Foo<'b>,)>`
+              found trait `Fn<(&Foo<'_>,)>`
+
+error: implementation of `FnOnce` is not general enough
+  --> $DIR/rfc1623-2.rs:28:8
+   |
+LL |     f: &id,
+   |        ^^^ implementation of `FnOnce` is not general enough
+   |
+   = note: `fn(&'2 Foo<'_>) -> &'2 Foo<'_> {id::<&'2 Foo<'_>>}` must implement `FnOnce<(&'1 Foo<'b>,)>`, for any lifetime `'1`...
+   = note: ...but it actually implements `FnOnce<(&'2 Foo<'_>,)>`, for some specific lifetime `'2`
+
+error: implementation of `FnOnce` is not general enough
+  --> $DIR/rfc1623-2.rs:28:8
+   |
+LL |     f: &id,
+   |        ^^^ implementation of `FnOnce` is not general enough
+   |
+   = note: `fn(&Foo<'2>) -> &Foo<'2> {id::<&Foo<'2>>}` must implement `FnOnce<(&'a Foo<'1>,)>`, for any lifetime `'1`...
+   = note: ...but it actually implements `FnOnce<(&Foo<'2>,)>`, for some specific lifetime `'2`
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/rfcs/rfc-1623-static/rfc1623-3.rs b/tests/ui/rfcs/rfc-1623-static/rfc1623-3.rs
new file mode 100644
index 000000000..26fa6fdb5
--- /dev/null
+++ b/tests/ui/rfcs/rfc-1623-static/rfc1623-3.rs
@@ -0,0 +1,14 @@
+#![allow(dead_code)]
+
+fn non_elidable<'a, 'b>(a: &'a u8, b: &'b u8) -> &'a u8 {
+    a
+}
+
+// the boundaries of elision
+static NON_ELIDABLE_FN: &fn(&u8, &u8) -> &u8 =
+//~^ ERROR missing lifetime specifier [E0106]
+    &(non_elidable as fn(&u8, &u8) -> &u8);
+    //~^ ERROR missing lifetime specifier [E0106]
+    //~| ERROR non-primitive cast
+
+fn main() {}
diff --git a/tests/ui/rfcs/rfc-1623-static/rfc1623-3.stderr b/tests/ui/rfcs/rfc-1623-static/rfc1623-3.stderr
new file mode 100644
index 000000000..77fc3f041
--- /dev/null
+++ b/tests/ui/rfcs/rfc-1623-static/rfc1623-3.stderr
@@ -0,0 +1,35 @@
+error[E0106]: missing lifetime specifier
+  --> $DIR/rfc1623-3.rs:8:42
+   |
+LL | static NON_ELIDABLE_FN: &fn(&u8, &u8) -> &u8 =
+   |                             ---  ---     ^ expected named lifetime parameter
+   |
+   = help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or argument 2
+   = note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html
+help: consider making the type lifetime-generic with a new `'a` lifetime
+   |
+LL | static NON_ELIDABLE_FN: &for<'a> fn(&'a u8, &'a u8) -> &'a u8 =
+   |                          +++++++     ++      ++         ++
+
+error[E0106]: missing lifetime specifier
+  --> $DIR/rfc1623-3.rs:10:39
+   |
+LL |     &(non_elidable as fn(&u8, &u8) -> &u8);
+   |                          ---  ---     ^ expected named lifetime parameter
+   |
+   = help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or argument 2
+help: consider making the type lifetime-generic with a new `'a` lifetime
+   |
+LL |     &(non_elidable as for<'a> fn(&'a u8, &'a u8) -> &'a u8);
+   |                       +++++++     ++      ++         ++
+
+error[E0605]: non-primitive cast: `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8 {non_elidable}` as `for<'a, 'b> fn(&'a u8, &'b u8) -> &u8`
+  --> $DIR/rfc1623-3.rs:10:6
+   |
+LL |     &(non_elidable as fn(&u8, &u8) -> &u8);
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ invalid cast
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0106, E0605.
+For more information about an error, try `rustc --explain E0106`.
diff --git a/tests/ui/rfcs/rfc-1623-static/rfc1623.rs b/tests/ui/rfcs/rfc-1623-static/rfc1623.rs
new file mode 100644
index 000000000..adaf25c6b
--- /dev/null
+++ b/tests/ui/rfcs/rfc-1623-static/rfc1623.rs
@@ -0,0 +1,75 @@
+// run-pass
+#![allow(unused_variables)]
+#![allow(non_upper_case_globals)]
+
+#![allow(dead_code)]
+
+// very simple test for a 'static static with default lifetime
+static STATIC_STR: &str = "&'static str";
+const CONST_STR: &str = "&'static str";
+
+// this should be the same as without default:
+static EXPLICIT_STATIC_STR: &'static str = "&'static str";
+const EXPLICIT_CONST_STR: &'static str = "&'static str";
+
+// a function that elides to an unbound lifetime for both in- and output
+fn id_u8_slice(arg: &[u8]) -> &[u8] {
+    arg
+}
+
+// one with a function, argument elided
+static STATIC_SIMPLE_FN: &fn(&[u8]) -> &[u8] = &(id_u8_slice as fn(&[u8]) -> &[u8]);
+const CONST_SIMPLE_FN: &fn(&[u8]) -> &[u8] = &(id_u8_slice as fn(&[u8]) -> &[u8]);
+
+// this should be the same as without elision
+static STATIC_NON_ELIDED_fN: &for<'a> fn(&'a [u8]) -> &'a [u8] =
+    &(id_u8_slice as for<'a> fn(&'a [u8]) -> &'a [u8]);
+const CONST_NON_ELIDED_fN: &for<'a> fn(&'a [u8]) -> &'a [u8] =
+    &(id_u8_slice as for<'a> fn(&'a [u8]) -> &'a [u8]);
+
+// another function that elides, each to a different unbound lifetime
+fn multi_args(a: &u8, b: &u8, c: &u8) {}
+
+static STATIC_MULTI_FN: &fn(&u8, &u8, &u8) = &(multi_args as fn(&u8, &u8, &u8));
+const CONST_MULTI_FN: &fn(&u8, &u8, &u8) = &(multi_args as fn(&u8, &u8, &u8));
+
+struct Foo<'a> {
+    bools: &'a [bool],
+}
+
+static STATIC_FOO: Foo = Foo { bools: &[true, false] };
+const CONST_FOO: Foo = Foo { bools: &[true, false] };
+
+type Bar<'a> = Foo<'a>;
+
+static STATIC_BAR: Bar = Bar { bools: &[true, false] };
+const CONST_BAR: Bar = Bar { bools: &[true, false] };
+
+type Baz<'a> = fn(&'a [u8]) -> Option<u8>;
+
+fn baz(e: &[u8]) -> Option<u8> {
+    e.first().map(|x| *x)
+}
+
+static STATIC_BAZ: &Baz = &(baz as Baz);
+const CONST_BAZ: &Baz = &(baz as Baz);
+
+static BYTES: &[u8] = &[1, 2, 3];
+
+fn main() {
+    // make sure that the lifetime is actually elided (and not defaulted)
+    let x = &[1u8, 2, 3];
+    STATIC_SIMPLE_FN(x);
+    CONST_SIMPLE_FN(x);
+
+    STATIC_BAZ(BYTES); // neees static lifetime
+    CONST_BAZ(BYTES);
+
+    // make sure this works with different lifetimes
+    let a = &1;
+    {
+        let b = &2;
+        let c = &3;
+        CONST_MULTI_FN(a, b, c);
+    }
+}