Auto merge of rust-lang#93933 - matthiaskrgr:rollup-1hjae6g, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - rust-lang#91908 (Add 2 tests)
 - rust-lang#93595 (fix ICE when parsing lifetime as function argument)
 - rust-lang#93757 (Add some known GAT bugs as tests)
 - rust-lang#93759 (Pretty print ItemKind::Use in rustfmt style)
 - rust-lang#93897 (linkchecker: fix panic on directory symlinks)
 - rust-lang#93898 (tidy: Extend error code check)
 - rust-lang#93928 (Add missing release notes for rust-lang#85200)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

RELEASES.md

@@ -156,6 +156,7 @@ Language
 - [Macro attributes may follow `#[derive]` and will see the original (pre-`cfg`) input.][87220]
 - [Accept curly-brace macros in expressions, like `m!{ .. }.method()` and `m!{ .. }?`.][88690]
 - [Allow panicking in constant evaluation.][89508]
+- [Ignore derived `Clone` and `Debug` implementations during dead code analysis.][85200]
 
 Compiler
 --------
@@ -216,6 +217,9 @@ Cargo
 Compatibility notes
 -------------------
 
+- [Ignore derived `Clone` and `Debug` implementations during dead code analysis.][85200]
+  This will break some builds that set `#![deny(dead_code)]`.
+
 Internal changes
 ----------------
 These changes provide no direct user facing benefits, but represent significant
@@ -224,6 +228,7 @@ and related tools.
 
 - [Added an experimental backend for codegen with `libgccjit`.][87260]
 
+[85200]: https://github.com/rust-lang/rust/pull/85200/
 [86191]: https://github.com/rust-lang/rust/pull/86191/
 [87220]: https://github.com/rust-lang/rust/pull/87220/
 [87260]: https://github.com/rust-lang/rust/pull/87260/

compiler/rustc_ast_pretty/src/pp/convenience.rs

@@ -75,6 +75,10 @@ impl Printer {
     }
 
     pub fn trailing_comma(&mut self) {
+        self.scan_break(BreakToken { pre_break: Some(','), ..BreakToken::default() });
+    }
+
+    pub fn trailing_comma_or_space(&mut self) {
         self.scan_break(BreakToken {
             blank_space: 1,
             pre_break: Some(','),

compiler/rustc_ast_pretty/src/pprust/state/expr.rs

@@ -142,7 +142,7 @@ impl<'a> State<'a> {
             if !field.is_last || has_rest {
                 self.word_space(",");
             } else {
-                self.trailing_comma();
+                self.trailing_comma_or_space();
             }
         }
         if has_rest {

compiler/rustc_ast_pretty/src/pprust/state/item.rs

@@ -1,5 +1,6 @@
 use crate::pp::Breaks::Inconsistent;
-use crate::pprust::state::{AnnNode, PrintState, State};
+use crate::pprust::state::delimited::IterDelimited;
+use crate::pprust::state::{AnnNode, PrintState, State, INDENT_UNIT};
 
 use rustc_ast as ast;
 use rustc_ast::GenericBound;
@@ -138,11 +139,10 @@ impl<'a> State<'a> {
                 self.end(); // end outer head-block
             }
             ast::ItemKind::Use(ref tree) => {
-                self.head(visibility_qualified(&item.vis, "use"));
+                self.print_visibility(&item.vis);
+                self.word_nbsp("use");
                 self.print_use_tree(tree);
                 self.word(";");
-                self.end(); // end inner head-block
-                self.end(); // end outer head-block
             }
             ast::ItemKind::Static(ref ty, mutbl, ref body) => {
                 let def = ast::Defaultness::Final;
@@ -615,8 +615,8 @@ impl<'a> State<'a> {
             ast::UseTreeKind::Simple(rename, ..) => {
                 self.print_path(&tree.prefix, false, 0);
                 if let Some(rename) = rename {
-                    self.space();
-                    self.word_space("as");
+                    self.nbsp();
+                    self.word_nbsp("as");
                     self.print_ident(rename);
                 }
             }
@@ -628,16 +628,36 @@ impl<'a> State<'a> {
                 self.word("*");
             }
             ast::UseTreeKind::Nested(ref items) => {
-                if tree.prefix.segments.is_empty() {
-                    self.word("{");
-                } else {
+                if !tree.prefix.segments.is_empty() {
                     self.print_path(&tree.prefix, false, 0);
-                    self.word("::{");
+                    self.word("::");
+                }
+                if items.is_empty() {
+                    self.word("{}");
+                } else if items.len() == 1 {
+                    self.print_use_tree(&items[0].0);
+                } else {
+                    self.cbox(INDENT_UNIT);
+                    self.word("{");
+                    self.zerobreak();
+                    self.ibox(0);
+                    for use_tree in items.iter().delimited() {
+                        self.print_use_tree(&use_tree.0);
+                        if !use_tree.is_last {
+                            self.word(",");
+                            if let ast::UseTreeKind::Nested(_) = use_tree.0.kind {
+                                self.hardbreak();
+                            } else {
+                                self.space();
+                            }
+                        }
+                    }
+                    self.end();
+                    self.trailing_comma();
+                    self.offset(-INDENT_UNIT);
+                    self.word("}");
+                    self.end();
                 }
-                self.commasep(Inconsistent, &items, |this, &(ref tree, _)| {
-                    this.print_use_tree(tree)
-                });
-                self.word("}");
             }
         }
     }

compiler/rustc_error_codes/src/error_codes.rs

@@ -97,6 +97,7 @@ E0184: include_str!("./error_codes/E0184.md"),
 E0185: include_str!("./error_codes/E0185.md"),
 E0186: include_str!("./error_codes/E0186.md"),
 E0191: include_str!("./error_codes/E0191.md"),
+E0192: include_str!("./error_codes/E0192.md"),
 E0193: include_str!("./error_codes/E0193.md"),
 E0195: include_str!("./error_codes/E0195.md"),
 E0197: include_str!("./error_codes/E0197.md"),
@@ -522,7 +523,6 @@ E0787: include_str!("./error_codes/E0787.md"),
 //  E0188, // can not cast an immutable reference to a mutable pointer
 //  E0189, // deprecated: can only cast a boxed pointer to a boxed object
 //  E0190, // deprecated: can only cast a &-pointer to an &-object
-//  E0192, // negative impl only applicable to auto traits
 //  E0194, // merged into E0403
 //  E0196, // cannot determine a type for this closure
     E0208,

compiler/rustc_error_codes/src/error_codes/E0192.md

@@ -1,15 +1,17 @@
+#### Note: this error code is no longer emitted by the compiler.
+
 A negative impl was added on a trait implementation.
 
 Erroneous code example:
 
-```compile_fail,E0192
+```compile_fail
 trait Trait {
     type Bar;
 }
 
 struct Foo;
 
-impl !Trait for Foo { } //~ ERROR E0192
+impl !Trait for Foo { } //~ ERROR
 
 fn main() {}
 ```

compiler/rustc_parse/src/parser/expr.rs

@@ -1457,9 +1457,9 @@ impl<'a> Parser<'a> {
         } else if self.check(&token::OpenDelim(token::Brace)) || self.token.is_whole_block() {
             self.parse_block_expr(label, lo, BlockCheckMode::Default, attrs)
         } else if !ate_colon && (self.check(&TokenKind::Comma) || self.check(&TokenKind::Gt)) {
-            // We're probably inside of a `Path<'a>` that needs a turbofish, so suppress the
-            // "must be followed by a colon" error, and the "expected one of" error.
-            self.diagnostic().delay_span_bug(lo, "this label wasn't parsed correctly");
+            // We're probably inside of a `Path<'a>` that needs a turbofish
+            let msg = "expected `while`, `for`, `loop` or `{` after a label";
+            self.struct_span_err(self.token.span, msg).span_label(self.token.span, msg).emit();
             consume_colon = false;
             Ok(self.mk_expr_err(lo))
         } else {

src/test/pretty/use-tree.rs

@@ -0,0 +1,23 @@
+// pp-exact
+// edition:2021
+
+#![allow(unused_imports)]
+
+use ::std::fmt::{self, Debug, Display, Write as _};
+
+use core::option::Option::*;
+
+use core::{
+    cmp::{Eq, Ord, PartialEq, PartialOrd},
+    convert::{AsMut, AsRef, From, Into},
+    iter::{
+        DoubleEndedIterator, ExactSizeIterator, Extend, FromIterator,
+        IntoIterator, Iterator,
+    },
+    marker::{
+        Copy as Copy, Send as Send, Sized as Sized, Sync as Sync, Unpin as U,
+    },
+    ops::{*, Drop, Fn, FnMut, FnOnce},
+};
+
+fn main() {}

src/test/ui/associated-types/issue-91069.rs

@@ -0,0 +1,24 @@
+// check-pass
+
+pub trait Associate {
+    type Associated;
+}
+
+pub struct Wrap<'a> {
+    pub field: &'a i32,
+}
+
+pub trait Create<T> {
+    fn create() -> Self;
+}
+
+pub fn oh_no<'a, T>()
+where
+    Wrap<'a>: Associate,
+    <Wrap<'a> as Associate>::Associated: Create<T>,
+{
+    <Wrap<'a> as Associate>::Associated::create();
+}
+
+
+pub fn main() {}

src/test/ui/generic-associated-types/bugs/issue-80626.rs

@@ -0,0 +1,17 @@
+// check-fail
+
+// This should pass, but it requires `Sized` to be coinductive.
+
+#![feature(generic_associated_types)]
+
+trait Allocator {
+    type Allocated<T>;
+}
+
+enum LinkedList<A: Allocator> {
+    Head,
+    Next(A::Allocated<Self>)
+    //~^ overflow
+}
+
+fn main() {}

src/test/ui/generic-associated-types/bugs/issue-80626.stderr

@@ -0,0 +1,20 @@
+error[E0275]: overflow evaluating the requirement `LinkedList<A>: Sized`
+  --> $DIR/issue-80626.rs:13:10
+   |
+LL |     Next(A::Allocated<Self>)
+   |          ^^^^^^^^^^^^^^^^^^
+   |
+   = note: no field of an enum variant may have a dynamically sized type
+   = help: change the field's type to have a statically known size
+help: borrowed types always have a statically known size
+   |
+LL |     Next(&A::Allocated<Self>)
+   |          +
+help: the `Box` type always has a statically known size and allocates its contents in the heap
+   |
+LL |     Next(Box<A::Allocated<Self>>)
+   |          ++++                  +
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0275`.

src/test/ui/generic-associated-types/bugs/issue-86218.rs

@@ -0,0 +1,27 @@
+// check-fail
+
+// This should pass, but seems to run into a TAIT issue.
+
+#![feature(generic_associated_types)]
+#![feature(type_alias_impl_trait)]
+
+pub trait Stream {
+    type Item;
+}
+
+impl Stream for () {
+    type Item = i32;
+}
+
+trait Yay<AdditionalValue> {
+    type InnerStream<'s>: Stream<Item = i32> + 's;
+    fn foo<'s>() -> Self::InnerStream<'s>;
+}
+
+impl<'a> Yay<&'a ()> for () {
+    type InnerStream<'s> = impl Stream<Item = i32> + 's;
+    //~^ the type
+    fn foo<'s>() -> Self::InnerStream<'s> { todo!() }
+}
+
+fn main() {}

src/test/ui/generic-associated-types/bugs/issue-86218.stderr

@@ -0,0 +1,15 @@
+error[E0477]: the type `impl Stream<Item = i32>` does not fulfill the required lifetime
+  --> $DIR/issue-86218.rs:22:28
+   |
+LL |     type InnerStream<'s> = impl Stream<Item = i32> + 's;
+   |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: type must outlive the lifetime `'s` as defined here as required by this binding
+  --> $DIR/issue-86218.rs:22:22
+   |
+LL |     type InnerStream<'s> = impl Stream<Item = i32> + 's;
+   |                      ^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0477`.

src/test/ui/generic-associated-types/bugs/issue-87735.rs

@@ -0,0 +1,45 @@
+// check-fail
+
+// This should pass, but we need an extension of implied bounds (probably).
+
+#![feature(generic_associated_types)]
+
+pub trait AsRef2 {
+  type Output<'a> where Self: 'a;
+
+  fn as_ref2<'a>(&'a self) -> Self::Output<'a>;
+}
+
+impl<T> AsRef2 for Vec<T> {
+  type Output<'a> where Self: 'a = &'a [T];
+
+  fn as_ref2<'a>(&'a self) -> Self::Output<'a> {
+    &self[..]
+  }
+}
+
+#[derive(Debug)]
+struct Foo<T>(T);
+#[derive(Debug)]
+struct FooRef<'a, U>(&'a [U]);
+
+impl<'b, T, U> AsRef2 for Foo<T> //~ the type parameter
+where
+    // * `for<'b, 'c> T: AsRef2<Output<'b> = &'c [U]>>` does not work
+    //
+    // * `U` is unconstrained but should be allowed in this context because `Output` is
+    // an associated type
+    T: AsRef2<Output<'b> = &'b [U]>,
+    U: 'b
+{
+  type Output<'a> where Self: 'a = FooRef<'a, U>;
+
+  fn as_ref2<'a>(&'a self) -> Self::Output<'a> {
+    FooRef(self.0.as_ref2())
+  }
+}
+
+fn main() {
+    let foo = Foo(vec![1, 2, 3]);
+    dbg!(foo.as_ref2());
+}

src/test/ui/generic-associated-types/bugs/issue-87735.stderr

@@ -0,0 +1,9 @@
+error[E0207]: the type parameter `U` is not constrained by the impl trait, self type, or predicates
+  --> $DIR/issue-87735.rs:26:13
+   |
+LL | impl<'b, T, U> AsRef2 for Foo<T>
+   |             ^ unconstrained type parameter
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0207`.

src/test/ui/generic-associated-types/bugs/issue-87748.rs

@@ -0,0 +1,22 @@
+// check-fail
+
+// This should pass, but unnormalized input args aren't treated as implied.
+
+#![feature(generic_associated_types)]
+
+trait MyTrait {
+    type Assoc<'a, 'b> where 'b: 'a;
+    fn do_sth(arg: Self::Assoc<'_, '_>);
+}
+
+struct Foo;
+
+impl MyTrait for Foo {
+    type Assoc<'a, 'b> where 'b: 'a = u32;
+
+    fn do_sth(_: u32) {} //~ lifetime bound
+    // fn do_sth(_: Self::Assoc<'static, 'static>) {}
+    // fn do_sth(_: Self::Assoc<'_, '_>) {}
+}
+
+fn main() {}