Auto merge of #66908 - Centril:rollup-26givp6, r=Centril

Rollup of 9 pull requests

Successful merges:

 - #66612 (Initial implementation of or-pattern usefulness checking)
 - #66705 (Atomic as_mut_ptr)
 - #66759 (impl TrustedLen for vec::Drain)
 - #66858 (Use LLVMAddAnalysisPasses instead of Rust's wrapper)
 - #66870 (SimplifyArmIdentity only for locals with the same type)
 - #66883 (rustc_typeck: gate AnonConst's generics on feature(const_generics).)
 - #66889 (Make python-generated source files compatible with rustfmt)
 - #66894 (Remove unneeded prelude imports in libcore tests)
 - #66895 (Feature gating *declarations* => new crate `rustc_feature`)

Failed merges:

 - #66905 (rustc_plugin: Remove some remaining plugin features)

r? @ghost

8 files changed, 333 insertions, 0 deletions

diff --git a/src/test/mir-opt/simplify-arm-identity.rs b/src/test/mir-opt/simplify-arm-identity.rs
new file mode 100644
index 00000000000..a8fa64255fb
--- /dev/null
+++ b/src/test/mir-opt/simplify-arm-identity.rs
@@ -0,0 +1,75 @@
+// Checks that `SimplifyArmIdentity` is not applied if enums have incompatible layouts.
+// Regression test for issue #66856.
+//
+// compile-flags: -Zmir-opt-level=2
+
+enum Src {
+    Foo(u8),
+    Bar,
+}
+
+enum Dst {
+    Foo(u8),
+}
+
+fn main() {
+    let e: Src = Src::Foo(0);
+    let _: Dst = match e {
+        Src::Foo(x) => Dst::Foo(x),
+        Src::Bar => Dst::Foo(0),
+    };
+}
+
+// END RUST SOURCE
+// START rustc.main.SimplifyArmIdentity.before.mir
+// fn main() -> () {
+//     ...
+//     bb0: {
+//         StorageLive(_1);
+//         ((_1 as Foo).0: u8) = const 0u8;
+//         discriminant(_1) = 0;
+//         StorageLive(_2);
+//         _3 = discriminant(_1);
+//         switchInt(move _3) -> [0isize: bb3, 1isize: bb1, otherwise: bb2];
+//     }
+//     bb1: {
+//         ((_2 as Foo).0: u8) = const 0u8;
+//         discriminant(_2) = 0;
+//         goto -> bb4;
+//     }
+//     ...
+//     bb3: {
+//         _4 = ((_1 as Foo).0: u8);
+//         ((_2 as Foo).0: u8) = move _4;
+//         discriminant(_2) = 0;
+//         goto -> bb4;
+//     }
+//     ...
+// }
+// END rustc.main.SimplifyArmIdentity.before.mir
+// START rustc.main.SimplifyArmIdentity.after.mir
+// fn main() -> () {
+//     ...
+//     bb0: {
+//         StorageLive(_1);
+//         ((_1 as Foo).0: u8) = const 0u8;
+//         discriminant(_1) = 0;
+//         StorageLive(_2);
+//         _3 = discriminant(_1);
+//         switchInt(move _3) -> [0isize: bb3, 1isize: bb1, otherwise: bb2];
+//     }
+//     bb1: {
+//         ((_2 as Foo).0: u8) = const 0u8;
+//         discriminant(_2) = 0;
+//         goto -> bb4;
+//     }
+//     ...
+//     bb3: {
+//         _4 = ((_1 as Foo).0: u8);
+//         ((_2 as Foo).0: u8) = move _4;
+//         discriminant(_2) = 0;
+//         goto -> bb4;
+//     }
+//     ...
+// }
+// END rustc.main.SimplifyArmIdentity.after.mir
diff --git a/src/test/ui/issues/issue-66851.rs b/src/test/ui/issues/issue-66851.rs
new file mode 100644
index 00000000000..72d62a30a33
--- /dev/null
+++ b/src/test/ui/issues/issue-66851.rs
@@ -0,0 +1,20 @@
+// This used to mis-compile because the mir-opt `SimplifyArmIdentity`
+// did not check that the types matched up in the `Ok(r)` branch.
+//
+// run-pass
+// compile-flags: -Zmir-opt-level=2
+
+#[derive(Debug, PartialEq, Eq)]
+enum SpecialsRes { Res(u64) }
+
+fn e103() -> SpecialsRes {
+    if let Ok(r) = "1".parse() {
+        SpecialsRes::Res(r)
+    } else {
+        SpecialsRes::Res(42)
+    }
+}
+
+fn main() {
+    assert_eq!(e103(), SpecialsRes::Res(1));
+}
diff --git a/src/test/ui/or-patterns/exhaustiveness-non-exhaustive.rs b/src/test/ui/or-patterns/exhaustiveness-non-exhaustive.rs
new file mode 100644
index 00000000000..d7c191bb5a2
--- /dev/null
+++ b/src/test/ui/or-patterns/exhaustiveness-non-exhaustive.rs
@@ -0,0 +1,26 @@
+#![feature(or_patterns)]
+#![feature(slice_patterns)]
+#![allow(incomplete_features)]
+#![deny(unreachable_patterns)]
+
+// We wrap patterns in a tuple because top-level or-patterns are special-cased for now.
+fn main() {
+    // Get the fatal error out of the way
+    match (0u8,) {
+        (0 | _,) => {}
+        //~^ ERROR or-patterns are not fully implemented yet
+    }
+
+    match (0u8, 0u8) {
+        //~^ ERROR non-exhaustive patterns: `(2u8..=std::u8::MAX, _)`
+        (0 | 1, 2 | 3) => {}
+    }
+    match ((0u8,),) {
+        //~^ ERROR non-exhaustive patterns: `((4u8..=std::u8::MAX))`
+        ((0 | 1,) | (2 | 3,),) => {},
+    }
+    match (Some(0u8),) {
+        //~^ ERROR non-exhaustive patterns: `(Some(2u8..=std::u8::MAX))`
+        (None | Some(0 | 1),) => {}
+    }
+}
diff --git a/src/test/ui/or-patterns/exhaustiveness-non-exhaustive.stderr b/src/test/ui/or-patterns/exhaustiveness-non-exhaustive.stderr
new file mode 100644
index 00000000000..e6aa157d278
--- /dev/null
+++ b/src/test/ui/or-patterns/exhaustiveness-non-exhaustive.stderr
@@ -0,0 +1,33 @@
+error[E0004]: non-exhaustive patterns: `(2u8..=std::u8::MAX, _)` not covered
+  --> $DIR/exhaustiveness-non-exhaustive.rs:14:11
+   |
+LL |     match (0u8, 0u8) {
+   |           ^^^^^^^^^^ pattern `(2u8..=std::u8::MAX, _)` not covered
+   |
+   = help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms
+
+error[E0004]: non-exhaustive patterns: `((4u8..=std::u8::MAX))` not covered
+  --> $DIR/exhaustiveness-non-exhaustive.rs:18:11
+   |
+LL |     match ((0u8,),) {
+   |           ^^^^^^^^^ pattern `((4u8..=std::u8::MAX))` not covered
+   |
+   = help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms
+
+error[E0004]: non-exhaustive patterns: `(Some(2u8..=std::u8::MAX))` not covered
+  --> $DIR/exhaustiveness-non-exhaustive.rs:22:11
+   |
+LL |     match (Some(0u8),) {
+   |           ^^^^^^^^^^^^ pattern `(Some(2u8..=std::u8::MAX))` not covered
+   |
+   = help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms
+
+error: or-patterns are not fully implemented yet
+  --> $DIR/exhaustiveness-non-exhaustive.rs:10:10
+   |
+LL |         (0 | _,) => {}
+   |          ^^^^^
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0004`.
diff --git a/src/test/ui/or-patterns/exhaustiveness-pass.rs b/src/test/ui/or-patterns/exhaustiveness-pass.rs
new file mode 100644
index 00000000000..62a851719f9
--- /dev/null
+++ b/src/test/ui/or-patterns/exhaustiveness-pass.rs
@@ -0,0 +1,40 @@
+#![feature(or_patterns)]
+#![feature(slice_patterns)]
+#![allow(incomplete_features)]
+#![deny(unreachable_patterns)]
+
+// We wrap patterns in a tuple because top-level or-patterns are special-cased for now.
+fn main() {
+    // Get the fatal error out of the way
+    match (0u8,) {
+        (0 | _,) => {}
+        //~^ ERROR or-patterns are not fully implemented yet
+    }
+
+    match (0u8,) {
+        (1 | 2,) => {}
+        _ => {}
+    }
+
+    match (0u8,) {
+        (1 | 1,) => {} // FIXME(or_patterns): redundancy not detected for now.
+        _ => {}
+    }
+    match (0u8, 0u8) {
+        (1 | 2, 3 | 4) => {}
+        (1, 2) => {}
+        (2, 1) => {}
+        _ => {}
+    }
+    match (Some(0u8),) {
+        (None | Some(0 | 1),) => {}
+        (Some(2..=255),) => {}
+    }
+    match ((0u8,),) {
+        ((0 | 1,) | (2 | 3,),) => {},
+        ((_,),) => {},
+    }
+    match (&[0u8][..],) {
+        ([] | [0 | 1..=255] | [_, ..],) => {},
+    }
+}
diff --git a/src/test/ui/or-patterns/exhaustiveness-pass.stderr b/src/test/ui/or-patterns/exhaustiveness-pass.stderr
new file mode 100644
index 00000000000..1f4278c4b80
--- /dev/null
+++ b/src/test/ui/or-patterns/exhaustiveness-pass.stderr
@@ -0,0 +1,8 @@
+error: or-patterns are not fully implemented yet
+  --> $DIR/exhaustiveness-pass.rs:10:10
+   |
+LL |         (0 | _,) => {}
+   |          ^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/or-patterns/exhaustiveness-unreachable-pattern.rs b/src/test/ui/or-patterns/exhaustiveness-unreachable-pattern.rs
new file mode 100644
index 00000000000..2cd8ca2dbac
--- /dev/null
+++ b/src/test/ui/or-patterns/exhaustiveness-unreachable-pattern.rs
@@ -0,0 +1,51 @@
+#![feature(or_patterns)]
+#![feature(slice_patterns)]
+#![allow(incomplete_features)]
+#![deny(unreachable_patterns)]
+
+// We wrap patterns in a tuple because top-level or-patterns are special-cased for now.
+fn main() {
+    // Get the fatal error out of the way
+    match (0u8,) {
+        (0 | _,) => {}
+        //~^ ERROR or-patterns are not fully implemented yet
+    }
+
+    match (0u8,) {
+        (1 | 2,) => {}
+        (1,) => {} //~ ERROR unreachable pattern
+        _ => {}
+    }
+    match (0u8,) {
+        (1 | 2,) => {}
+        (2,) => {} //~ ERROR unreachable pattern
+        _ => {}
+    }
+    match (0u8,) {
+        (1,) => {}
+        (2,) => {}
+        (1 | 2,) => {} //~ ERROR unreachable pattern
+        _ => {}
+    }
+    match (0u8, 0u8) {
+        (1 | 2, 3 | 4) => {}
+        (1, 3) => {} //~ ERROR unreachable pattern
+        (1, 4) => {} //~ ERROR unreachable pattern
+        (2, 4) => {} //~ ERROR unreachable pattern
+        (2 | 1, 4) => {} //~ ERROR unreachable pattern
+        (1, 5 | 6) => {}
+        (1, 4 | 5) => {} //~ ERROR unreachable pattern
+        _ => {}
+    }
+    match (Some(0u8),) {
+        (None | Some(1 | 2),) => {}
+        (Some(1),) => {} //~ ERROR unreachable pattern
+        (None,) => {} //~ ERROR unreachable pattern
+        _ => {}
+    }
+    match ((0u8,),) {
+        ((1 | 2,) | (3 | 4,),) => {},
+        ((1..=4,),) => {}, //~ ERROR unreachable pattern
+        _ => {},
+    }
+}
diff --git a/src/test/ui/or-patterns/exhaustiveness-unreachable-pattern.stderr b/src/test/ui/or-patterns/exhaustiveness-unreachable-pattern.stderr
new file mode 100644
index 00000000000..a4d55d805c3
--- /dev/null
+++ b/src/test/ui/or-patterns/exhaustiveness-unreachable-pattern.stderr
@@ -0,0 +1,80 @@
+error: unreachable pattern
+  --> $DIR/exhaustiveness-unreachable-pattern.rs:16:9
+   |
+LL |         (1,) => {}
+   |         ^^^^
+   |
+note: lint level defined here
+  --> $DIR/exhaustiveness-unreachable-pattern.rs:4:9
+   |
+LL | #![deny(unreachable_patterns)]
+   |         ^^^^^^^^^^^^^^^^^^^^
+
+error: unreachable pattern
+  --> $DIR/exhaustiveness-unreachable-pattern.rs:21:9
+   |
+LL |         (2,) => {}
+   |         ^^^^
+
+error: unreachable pattern
+  --> $DIR/exhaustiveness-unreachable-pattern.rs:27:9
+   |
+LL |         (1 | 2,) => {}
+   |         ^^^^^^^^
+
+error: unreachable pattern
+  --> $DIR/exhaustiveness-unreachable-pattern.rs:32:9
+   |
+LL |         (1, 3) => {}
+   |         ^^^^^^
+
+error: unreachable pattern
+  --> $DIR/exhaustiveness-unreachable-pattern.rs:33:9
+   |
+LL |         (1, 4) => {}
+   |         ^^^^^^
+
+error: unreachable pattern
+  --> $DIR/exhaustiveness-unreachable-pattern.rs:34:9
+   |
+LL |         (2, 4) => {}
+   |         ^^^^^^
+
+error: unreachable pattern
+  --> $DIR/exhaustiveness-unreachable-pattern.rs:35:9
+   |
+LL |         (2 | 1, 4) => {}
+   |         ^^^^^^^^^^
+
+error: unreachable pattern
+  --> $DIR/exhaustiveness-unreachable-pattern.rs:37:9
+   |
+LL |         (1, 4 | 5) => {}
+   |         ^^^^^^^^^^
+
+error: unreachable pattern
+  --> $DIR/exhaustiveness-unreachable-pattern.rs:42:9
+   |
+LL |         (Some(1),) => {}
+   |         ^^^^^^^^^^
+
+error: unreachable pattern
+  --> $DIR/exhaustiveness-unreachable-pattern.rs:43:9
+   |
+LL |         (None,) => {}
+   |         ^^^^^^^
+
+error: unreachable pattern
+  --> $DIR/exhaustiveness-unreachable-pattern.rs:48:9
+   |
+LL |         ((1..=4,),) => {},
+   |         ^^^^^^^^^^^
+
+error: or-patterns are not fully implemented yet
+  --> $DIR/exhaustiveness-unreachable-pattern.rs:10:10
+   |
+LL |         (0 | _,) => {}
+   |          ^^^^^
+
+error: aborting due to 12 previous errors
+