Auto merge of #97910 - JohnTitor:rollup-gu3k0xl, r=JohnTitor

Rollup of 5 pull requests

Successful merges:

 - #95632 (impl Read and Write for VecDeque<u8>)
 - #95860 (Stabilize `$$` in Rust 1.63.0)
 - #97838 (hexagon: adapt test for upstream output changes)
 - #97843 (Relax mipsel-sony-psp's linker script)
 - #97874 (rewrite combine doc comment)

Failed merges:

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

9 files changed, 111 insertions, 89 deletions

diff --git a/compiler/rustc_expand/src/mbe/quoted.rs b/compiler/rustc_expand/src/mbe/quoted.rs
index 707cb73f097..d4b8563a036 100644
--- a/compiler/rustc_expand/src/mbe/quoted.rs
+++ b/compiler/rustc_expand/src/mbe/quoted.rs
@@ -234,8 +234,6 @@ fn parse_tree(
                             sess,
                             &Token { kind: token::Dollar, span },
                         );
-                    } else {
-                        maybe_emit_macro_metavar_expr_feature(features, sess, span);
                     }
                     TokenTree::token(token::Dollar, span)
                 }
diff --git a/compiler/rustc_infer/src/infer/combine.rs b/compiler/rustc_infer/src/infer/combine.rs
index 534106ac446..120e57ecebd 100644
--- a/compiler/rustc_infer/src/infer/combine.rs
+++ b/compiler/rustc_infer/src/infer/combine.rs
@@ -1,26 +1,26 @@
-///////////////////////////////////////////////////////////////////////////
-// # Type combining
-//
-// There are four type combiners: equate, sub, lub, and glb.  Each
-// implements the trait `Combine` and contains methods for combining
-// two instances of various things and yielding a new instance.  These
-// combiner methods always yield a `Result<T>`.  There is a lot of
-// common code for these operations, implemented as default methods on
-// the `Combine` trait.
-//
-// Each operation may have side-effects on the inference context,
-// though these can be unrolled using snapshots. On success, the
-// LUB/GLB operations return the appropriate bound. The Eq and Sub
-// operations generally return the first operand.
-//
-// ## Contravariance
-//
-// When you are relating two things which have a contravariant
-// relationship, you should use `contratys()` or `contraregions()`,
-// rather than inversing the order of arguments!  This is necessary
-// because the order of arguments is not relevant for LUB and GLB.  It
-// is also useful to track which value is the "expected" value in
-// terms of error reporting.
+//! There are four type combiners: [Equate], [Sub], [Lub], and [Glb].
+//! Each implements the trait [TypeRelation] and contains methods for
+//! combining two instances of various things and yielding a new instance.
+//! These combiner methods always yield a `Result<T>`. To relate two
+//! types, you can use `infcx.at(cause, param_env)` which then allows
+//! you to use the relevant methods of [At](super::at::At).
+//!
+//! Combiners mostly do their specific behavior and then hand off the
+//! bulk of the work to [InferCtxt::super_combine_tys] and
+//! [InferCtxt::super_combine_consts].
+//!
+//! Combining two types may have side-effects on the inference contexts
+//! which can be undone by using snapshots. You probably want to use
+//! either [InferCtxt::commit_if_ok] or [InferCtxt::probe].
+//!
+//! On success, the  LUB/GLB operations return the appropriate bound. The
+//! return value of `Equate` or `Sub` shouldn't really be used.
+//!
+//! ## Contravariance
+//!
+//! We explicitly track which argument is expected using
+//! [TypeRelation::a_is_expected], so when dealing with contravariance
+//! this should be correctly updated.
 
 use super::equate::Equate;
 use super::glb::Glb;
diff --git a/compiler/rustc_target/src/spec/mipsel_sony_psp.rs b/compiler/rustc_target/src/spec/mipsel_sony_psp.rs
index 45966b97d6a..03e0934ea5e 100644
--- a/compiler/rustc_target/src/spec/mipsel_sony_psp.rs
+++ b/compiler/rustc_target/src/spec/mipsel_sony_psp.rs
@@ -6,7 +6,8 @@ const LINKER_SCRIPT: &str = include_str!("./mipsel_sony_psp_linker_script.ld");
 
 pub fn target() -> Target {
     let mut pre_link_args = LinkArgs::new();
-    pre_link_args.insert(LinkerFlavor::Lld(LldFlavor::Ld), vec!["--emit-relocs".into()]);
+    pre_link_args
+        .insert(LinkerFlavor::Lld(LldFlavor::Ld), vec!["--emit-relocs".into(), "--nmagic".into()]);
 
     Target {
         llvm_target: "mipsel-sony-psp".into(),
diff --git a/compiler/rustc_target/src/spec/mipsel_sony_psp_linker_script.ld b/compiler/rustc_target/src/spec/mipsel_sony_psp_linker_script.ld
index 1bd436d6f94..9eb35ad9f5d 100644
--- a/compiler/rustc_target/src/spec/mipsel_sony_psp_linker_script.ld
+++ b/compiler/rustc_target/src/spec/mipsel_sony_psp_linker_script.ld
@@ -7,14 +7,18 @@ SECTIONS
   /* Sort stubs for convenient ordering */
   .sceStub.text : { *(.sceStub.text) *(SORT(.sceStub.text.*)) }
 
+  /* PSP import library stub sections. Bundles together `.lib.stub.entry.*`
+   * sections for better `--gc-sections` support. */
+  .lib.stub.top : { *(.lib.stub.top) }
+  .lib.stub :     { *(.lib.stub) *(.lib.stub.entry.*) }
+  .lib.stub.btm : { *(.lib.stub.btm) }
+
   /* Keep these sections around, even though they may appear unused to the linker */
   .lib.ent.top :  { KEEP(*(.lib.ent.top)) }
   .lib.ent :      { KEEP(*(.lib.ent)) }
   .lib.ent.btm :  { KEEP(*(.lib.ent.btm)) }
-  .lib.stub.top : { KEEP(*(.lib.stub.top)) }
-  .lib.stub :     { KEEP(*(.lib.stub)) }
-  .lib.stub.btm : { KEEP(*(.lib.stub.btm)) }
-  .eh_frame_hdr : { KEEP(*(.eh_frame_hdr)) }
+
+  .eh_frame_hdr : { *(.eh_frame_hdr) }
 
   /* Add symbols for LLVM's libunwind */
   __eh_frame_hdr_start = SIZEOF(.eh_frame_hdr) > 0 ? ADDR(.eh_frame_hdr) : 0;
@@ -27,8 +31,15 @@ SECTIONS
   }
 
   /* These are explicitly listed to avoid being merged into .rodata */
-  .rodata.sceResident : { *(.rodata.sceResident) }
+  .rodata.sceResident : { *(.rodata.sceResident) *(.rodata.sceResident.*) }
   .rodata.sceModuleInfo : { *(.rodata.sceModuleInfo) }
   /* Sort NIDs for convenient ordering */
   .rodata.sceNid : { *(.rodata.sceNid) *(SORT(.rodata.sceNid.*)) }
+
+  .rodata : { *(.rodata .rodata.*) }
+  .data : { *(.data .data.*) }
+  .gcc_except_table : { *(.gcc_except_table .gcc_except_table.*) }
+  .bss : { *(.bss .bss.*) }
+
+  /DISCARD/ : { *(.rel.sceStub.text .MIPS.abiflags .reginfo) }
 }
diff --git a/library/std/src/io/impls.rs b/library/std/src/io/impls.rs
index 64d2457bce1..0ca58efe1fe 100644
--- a/library/std/src/io/impls.rs
+++ b/library/std/src/io/impls.rs
@@ -3,6 +3,7 @@ mod tests;
 
 use crate::alloc::Allocator;
 use crate::cmp;
+use crate::collections::VecDeque;
 use crate::fmt;
 use crate::io::{
     self, BufRead, ErrorKind, IoSlice, IoSliceMut, Read, ReadBuf, Seek, SeekFrom, Write,
@@ -410,3 +411,50 @@ impl<A: Allocator> Write for Vec<u8, A> {
         Ok(())
     }
 }
+
+/// Read is implemented for `VecDeque<u8>` by consuming bytes from the front of the `VecDeque`.
+#[stable(feature = "vecdeque_read_write", since = "1.63.0")]
+impl<A: Allocator> Read for VecDeque<u8, A> {
+    /// Fill `buf` with the contents of the "front" slice as returned by
+    /// [`as_slices`][`VecDeque::as_slices`]. If the contained byte slices of the `VecDeque` are
+    /// discontiguous, multiple calls to `read` will be needed to read the entire content.
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let (ref mut front, _) = self.as_slices();
+        let n = Read::read(front, buf)?;
+        self.drain(..n);
+        Ok(n)
+    }
+
+    #[inline]
+    fn read_buf(&mut self, buf: &mut ReadBuf<'_>) -> io::Result<()> {
+        let (ref mut front, _) = self.as_slices();
+        let n = cmp::min(buf.remaining(), front.len());
+        Read::read_buf(front, buf)?;
+        self.drain(..n);
+        Ok(())
+    }
+}
+
+/// Write is implemented for `VecDeque<u8>` by appending to the `VecDeque`, growing it as needed.
+#[stable(feature = "vecdeque_read_write", since = "1.63.0")]
+impl<A: Allocator> Write for VecDeque<u8, A> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.reserve(buf.len());
+        self.extend(buf);
+        Ok(buf.len())
+    }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        self.reserve(buf.len());
+        self.extend(buf);
+        Ok(())
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
diff --git a/src/test/assembly/asm/hexagon-types.rs b/src/test/assembly/asm/hexagon-types.rs
index de310c78488..eff9a0bb431 100644
--- a/src/test/assembly/asm/hexagon-types.rs
+++ b/src/test/assembly/asm/hexagon-types.rs
@@ -73,7 +73,7 @@ macro_rules! check_reg {
 
 // CHECK-LABEL: sym_static:
 // CHECK: InlineAsm Start
-// CHECK: r0 = #extern_static
+// CHECK: r0 = {{#+}}extern_static
 // CHECK: InlineAsm End
 #[no_mangle]
 pub unsafe fn sym_static() {
@@ -88,7 +88,7 @@ pub unsafe fn sym_static() {
 
 // CHECK-LABEL: sym_fn:
 // CHECK: InlineAsm Start
-// CHECK: r0 = #extern_func
+// CHECK: r0 = {{#+}}extern_func
 // CHECK: InlineAsm End
 #[no_mangle]
 pub unsafe fn sym_fn() {
@@ -108,7 +108,7 @@ pub unsafe fn sym_fn() {
 // CHECK: InlineAsm Start
 // CHECK: {
 // CHECK:   r{{[0-9]+}} = r0
-// CHECK:   memw(r1) = r{{[0-9]+}}
+// CHECK:   memw(r1{{(\+#0)?}}) = r{{[0-9]+}}
 // CHECK: }
 // CHECK: InlineAsm End
 #[no_mangle]
diff --git a/src/test/ui/macros/rfc-3086-metavar-expr/allowed-features.rs b/src/test/ui/macros/rfc-3086-metavar-expr/allowed-features.rs
new file mode 100644
index 00000000000..c248c46f52c
--- /dev/null
+++ b/src/test/ui/macros/rfc-3086-metavar-expr/allowed-features.rs
@@ -0,0 +1,12 @@
+// check-pass
+
+macro_rules! dollar_dollar {
+    () => {
+        macro_rules! bar {
+            ( $$( $$any:tt )* ) => { $$( $$any )* };
+        }
+    };
+}
+
+fn main() {
+}
diff --git a/src/test/ui/macros/rfc-3086-metavar-expr/required-feature.rs b/src/test/ui/macros/rfc-3086-metavar-expr/required-features.rs
index b4fef11f1e2..cce3e578aea 100644
--- a/src/test/ui/macros/rfc-3086-metavar-expr/required-feature.rs
+++ b/src/test/ui/macros/rfc-3086-metavar-expr/required-features.rs
@@ -5,18 +5,6 @@ macro_rules! count {
     };
 }
 
-macro_rules! dollar_dollar {
-    () => {
-        macro_rules! bar {
-            ( $$( $$any:tt )* ) => { $$( $$any )* };
-            //~^ ERROR meta-variable expressions are unstable
-            //~| ERROR meta-variable expressions are unstable
-            //~| ERROR meta-variable expressions are unstable
-            //~| ERROR meta-variable expressions are unstable
-        }
-    };
-}
-
 macro_rules! index {
     ( $( $e:stmt ),* ) => {
         $( ${ignore(e)} ${index()} )*
diff --git a/src/test/ui/macros/rfc-3086-metavar-expr/required-feature.stderr b/src/test/ui/macros/rfc-3086-metavar-expr/required-features.stderr
index ecf598b104d..5efd3b10442 100644
--- a/src/test/ui/macros/rfc-3086-metavar-expr/required-feature.stderr
+++ b/src/test/ui/macros/rfc-3086-metavar-expr/required-features.stderr
@@ -1,5 +1,5 @@
 error[E0658]: meta-variable expressions are unstable
-  --> $DIR/required-feature.rs:3:10
+  --> $DIR/required-features.rs:3:10
    |
 LL |         ${ count(e) }
    |          ^^^^^^^^^^^^
@@ -8,43 +8,7 @@ LL |         ${ count(e) }
    = help: add `#![feature(macro_metavar_expr)]` to the crate attributes to enable
 
 error[E0658]: meta-variable expressions are unstable
-  --> $DIR/required-feature.rs:11:16
-   |
-LL |             ( $$( $$any:tt )* ) => { $$( $$any )* };
-   |                ^
-   |
-   = note: see issue #83527 <https://github.com/rust-lang/rust/issues/83527> for more information
-   = help: add `#![feature(macro_metavar_expr)]` to the crate attributes to enable
-
-error[E0658]: meta-variable expressions are unstable
-  --> $DIR/required-feature.rs:11:20
-   |
-LL |             ( $$( $$any:tt )* ) => { $$( $$any )* };
-   |                    ^
-   |
-   = note: see issue #83527 <https://github.com/rust-lang/rust/issues/83527> for more information
-   = help: add `#![feature(macro_metavar_expr)]` to the crate attributes to enable
-
-error[E0658]: meta-variable expressions are unstable
-  --> $DIR/required-feature.rs:11:39
-   |
-LL |             ( $$( $$any:tt )* ) => { $$( $$any )* };
-   |                                       ^
-   |
-   = note: see issue #83527 <https://github.com/rust-lang/rust/issues/83527> for more information
-   = help: add `#![feature(macro_metavar_expr)]` to the crate attributes to enable
-
-error[E0658]: meta-variable expressions are unstable
-  --> $DIR/required-feature.rs:11:43
-   |
-LL |             ( $$( $$any:tt )* ) => { $$( $$any )* };
-   |                                           ^
-   |
-   = note: see issue #83527 <https://github.com/rust-lang/rust/issues/83527> for more information
-   = help: add `#![feature(macro_metavar_expr)]` to the crate attributes to enable
-
-error[E0658]: meta-variable expressions are unstable
-  --> $DIR/required-feature.rs:22:13
+  --> $DIR/required-features.rs:10:13
    |
 LL |         $( ${ignore(e)} ${index()} )*
    |             ^^^^^^^^^^^
@@ -53,7 +17,7 @@ LL |         $( ${ignore(e)} ${index()} )*
    = help: add `#![feature(macro_metavar_expr)]` to the crate attributes to enable
 
 error[E0658]: meta-variable expressions are unstable
-  --> $DIR/required-feature.rs:22:26
+  --> $DIR/required-features.rs:10:26
    |
 LL |         $( ${ignore(e)} ${index()} )*
    |                          ^^^^^^^^^
@@ -62,7 +26,7 @@ LL |         $( ${ignore(e)} ${index()} )*
    = help: add `#![feature(macro_metavar_expr)]` to the crate attributes to enable
 
 error[E0658]: meta-variable expressions are unstable
-  --> $DIR/required-feature.rs:30:19
+  --> $DIR/required-features.rs:18:19
    |
 LL |         0 $( + 1 ${ignore(i)} )*
    |                   ^^^^^^^^^^^
@@ -71,7 +35,7 @@ LL |         0 $( + 1 ${ignore(i)} )*
    = help: add `#![feature(macro_metavar_expr)]` to the crate attributes to enable
 
 error[E0658]: meta-variable expressions are unstable
-  --> $DIR/required-feature.rs:37:13
+  --> $DIR/required-features.rs:25:13
    |
 LL |         $( ${ignore(e)} ${length()} )*
    |             ^^^^^^^^^^^
@@ -80,7 +44,7 @@ LL |         $( ${ignore(e)} ${length()} )*
    = help: add `#![feature(macro_metavar_expr)]` to the crate attributes to enable
 
 error[E0658]: meta-variable expressions are unstable
-  --> $DIR/required-feature.rs:37:26
+  --> $DIR/required-features.rs:25:26
    |
 LL |         $( ${ignore(e)} ${length()} )*
    |                          ^^^^^^^^^^
@@ -88,6 +52,6 @@ LL |         $( ${ignore(e)} ${length()} )*
    = note: see issue #83527 <https://github.com/rust-lang/rust/issues/83527> for more information
    = help: add `#![feature(macro_metavar_expr)]` to the crate attributes to enable
 
-error: aborting due to 10 previous errors
+error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0658`.