rustc-dev-guide subtree update

src/doc/rustc-dev-guide/.github/workflows/rustc-pull.yml

@@ -12,6 +12,7 @@ jobs:
     uses: rust-lang/josh-sync/.github/workflows/rustc-pull.yml@main
     with:
       github-app-id: ${{ vars.APP_CLIENT_ID }}
+      pr-author: "workflows-rustc-dev-guide[bot]"
       zulip-stream-id: 196385
       zulip-bot-email:  "rustc-dev-guide-gha-notif-bot@rust-lang.zulipchat.com"
       pr-base-branch: main

src/doc/rustc-dev-guide/rust-version

@@ -1 +1 @@
-562dee4820c458d823175268e41601d4c060588a
+30d0309fa821f7a0984a9629e0d227ca3c0d2eda

src/doc/rustc-dev-guide/src/SUMMARY.md

@@ -72,6 +72,7 @@
     - [WASI](notification-groups/wasi.md)
     - [WebAssembly](notification-groups/wasm.md)
     - [Windows](notification-groups/windows.md)
+    - [GPU target](notification-groups/gpu-target.md)
 - [Licenses](./licenses.md)
 - [Editions](guides/editions.md)
 
@@ -100,9 +101,9 @@
 - [Parallel compilation](./parallel-rustc.md)
 - [Rustdoc internals](./rustdoc-internals.md)
     - [Search](./rustdoc-internals/search.md)
-	- [The `rustdoc-html` test suite](./rustdoc-internals/rustdoc-html-test-suite.md)
-	- [The `rustdoc-gui` test suite](./rustdoc-internals/rustdoc-gui-test-suite.md)
-	- [The `rustdoc-json` test suite](./rustdoc-internals/rustdoc-json-test-suite.md)
+    - [The `rustdoc-html` test suite](./rustdoc-internals/rustdoc-html-test-suite.md)
+    - [The `rustdoc-gui` test suite](./rustdoc-internals/rustdoc-gui-test-suite.md)
+    - [The `rustdoc-json` test suite](./rustdoc-internals/rustdoc-json-test-suite.md)
 - [GPU offload internals](./offload/internals.md)
     - [Installation](./offload/installation.md)
     - [Usage](./offload/usage.md)
@@ -189,6 +190,7 @@
         - [Significant changes and quirks](./solve/significant-changes.md)
         - [Sharing the trait solver with rust-analyzer](./solve/sharing-crates-with-rust-analyzer.md)
     - [`Unsize` and `CoerceUnsized` traits](./traits/unsize.md)
+    - [Having separate `Trait` and `Projection` bounds](./traits/separate-projection-bounds.md)
 - [Variance](./variance.md)
 - [Coherence checking](./coherence.md)
 - [HIR Type checking](./hir-typeck/summary.md)

src/doc/rustc-dev-guide/src/appendix/code-index.md

@@ -1,15 +1,15 @@
 # Code Index
 
-rustc has a lot of important data structures. This is an attempt to give some
-guidance on where to learn more about some of the key data structures of the
-compiler.
+rustc has a lot of important data structures.
+This is an attempt to give some guidance on where to learn more
+about some of the key data structures of the compiler.
 
 Item            |  Kind    | Short description           | Chapter            | Declaration
 ----------------|----------|-----------------------------|--------------------|-------------------
 `BodyId` | struct | One of four types of HIR node identifiers | [Identifiers in the HIR] | [compiler/rustc_hir/src/hir.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_hir/hir/struct.BodyId.html)
 `Compiler` | struct | Represents a compiler session and can be used to drive a compilation. | [The Rustc Driver and Interface] | [compiler/rustc_interface/src/interface.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_interface/interface/struct.Compiler.html)
 `ast::Crate` | struct | A syntax-level representation of a parsed crate | [The parser] | [compiler/rustc_ast/src/ast.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_ast/ast/struct.Crate.html)
-`rustc_hir::Crate` | struct | A more abstract, compiler-friendly form of a crate's AST | [The Hir] | [compiler/rustc_hir/src/hir.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_hir/hir/struct.Crate.html)
+`hir::Crate` | struct | A more abstract, compiler-friendly form of a crate's AST | [The Hir] | [compiler/rustc_middle/src/hir/mod.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/hir/struct.Crate.html)
 `DefId` | struct | One of four types of HIR node identifiers | [Identifiers in the HIR] | [compiler/rustc_hir/src/def_id.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_hir/def_id/struct.DefId.html)
 `Diag` | struct | A struct for a compiler diagnostic, such as an error or lint | [Emitting Diagnostics] | [compiler/rustc_errors/src/diagnostic.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_errors/struct.Diag.html)
 `DocContext` | struct | A state container used by rustdoc when crawling through a crate to gather its documentation | [Rustdoc] | [src/librustdoc/core.rs](https://github.com/rust-lang/rust/blob/HEAD/src/librustdoc/core.rs)

src/doc/rustc-dev-guide/src/const-eval/interpret.md

@@ -1,8 +1,9 @@
 # Interpreter
 
 The interpreter is a virtual machine for executing MIR without compiling to
-machine code. It is usually invoked via `tcx.const_eval_*` functions. The
-interpreter is shared between the compiler (for compile-time function
+machine code.
+It is usually invoked via `tcx.const_eval_*` functions.
+The interpreter is shared between the compiler (for compile-time function
 evaluation, CTFE) and the tool [Miri](https://github.com/rust-lang/miri/), which
 uses the same virtual machine to detect Undefined Behavior in (unsafe) Rust
 code.
@@ -26,7 +27,8 @@ The compiler needs to figure out the length of the array before being able to
 create items that use the type (locals, constants, function arguments, ...).
 
 To obtain the (in this case empty) parameter environment, one can call
-`let param_env = tcx.param_env(length_def_id);`. The `GlobalId` needed is
+`let param_env = tcx.param_env(length_def_id);`.
+The `GlobalId` needed is
 
 ```rust,ignore
 let gid = GlobalId {
@@ -36,7 +38,8 @@ let gid = GlobalId {
 ```
 
 Invoking `tcx.const_eval(param_env.and(gid))` will now trigger the creation of
-the MIR of the array length expression. The MIR will look something like this:
+the MIR of the array length expression.
+The MIR will look something like this:
 
 ```mir
 Foo::{{constant}}#0: usize = {
@@ -59,37 +62,45 @@ Before the evaluation, a virtual memory location (in this case essentially a
 `vec![u8; 4]` or `vec![u8; 8]`) is created for storing the evaluation result.
 
 At the start of the evaluation, `_0` and `_1` are
-`Operand::Immediate(Immediate::Scalar(ScalarMaybeUndef::Undef))`. This is quite
+`Operand::Immediate(Immediate::Scalar(ScalarMaybeUndef::Undef))`.
+This is quite
 a mouthful: [`Operand`] can represent either data stored somewhere in the
 [interpreter memory](#memory) (`Operand::Indirect`), or (as an optimization)
-immediate data stored in-line.  And [`Immediate`] can either be a single
+immediate data stored in-line.
+And [`Immediate`] can either be a single
 (potentially uninitialized) [scalar value][`Scalar`] (integer or thin pointer),
-or a pair of two of them. In our case, the single scalar value is *not* (yet)
-initialized.
+or a pair of two of them.
+In our case, the single scalar value is *not* (yet) initialized.
 
 When the initialization of `_1` is invoked, the value of the `FOO` constant is
 required, and triggers another call to `tcx.const_eval_*`, which will not be shown
-here. If the evaluation of FOO is successful, `42` will be subtracted from its
+here.
+If the evaluation of FOO is successful, `42` will be subtracted from its
 value `4096` and the result stored in `_1` as
 `Operand::Immediate(Immediate::ScalarPair(Scalar::Raw { data: 4054, .. },
-Scalar::Raw { data: 0, .. })`. The first part of the pair is the computed value,
-the second part is a bool that's true if an overflow happened. A `Scalar::Raw`
+Scalar::Raw { data: 0, .. })`.
+The first part of the pair is the computed value,
+the second part is a bool that's true if an overflow happened.
+A `Scalar::Raw`
 also stores the size (in bytes) of this scalar value; we are eliding that here.
 
-The next statement asserts that said boolean is `0`. In case the assertion
+The next statement asserts that said boolean is `0`.
+In case the assertion
 fails, its error message is used for reporting a compile-time error.
 
 Since it does not fail, `Operand::Immediate(Immediate::Scalar(Scalar::Raw {
 data: 4054, .. }))` is stored in the virtual memory it was allocated before the
-evaluation. `_0` always refers to that location directly.
+evaluation.
+`_0` always refers to that location directly.
 
 After the evaluation is done, the return value is converted from [`Operand`] to
 [`ConstValue`] by [`op_to_const`]: the former representation is geared towards
 what is needed *during* const evaluation, while [`ConstValue`] is shaped by the
 needs of the remaining parts of the compiler that consume the results of const
-evaluation.  As part of this conversion, for types with scalar values, even if
+evaluation.
+As part of this conversion, for types with scalar values, even if
 the resulting [`Operand`] is `Indirect`, it will return an immediate
-`ConstValue::Scalar(computed_value)` (instead of the usual `ConstValue::ByRef`).
+`ConstValue::Scalar(computed_value)` (instead of the usual `ConstValue::Indirect`).
 This makes using the result much more efficient and also more convenient, as no
 further queries need to be executed in order to get at something as simple as a
 `usize`.
@@ -107,12 +118,13 @@ the interpreter, but just use the cached result.
 
 The interpreter's outside-facing datastructures can be found in
 [rustc_middle/src/mir/interpret](https://github.com/rust-lang/rust/blob/HEAD/compiler/rustc_middle/src/mir/interpret).
-This is mainly the error enum and the [`ConstValue`] and [`Scalar`] types. A
-`ConstValue` can be either `Scalar` (a single `Scalar`, i.e., integer or thin
+This is mainly the error enum and the [`ConstValue`] and [`Scalar`] types.
+A `ConstValue` can be either `Scalar` (a single `Scalar`, i.e., integer or thin
 pointer), `Slice` (to represent byte slices and strings, as needed for pattern
-matching) or `ByRef`, which is used for anything else and refers to a virtual
-allocation. These allocations can be accessed via the methods on
-`tcx.interpret_interner`.  A `Scalar` is either some `Raw` integer or a pointer;
+matching) or `Indirect`, which is used for anything else and refers to a virtual
+allocation.
+These allocations can be accessed via the methods on `tcx.interpret_interner`.
+A `Scalar` is either some `Raw` integer or a pointer;
 see [the next section](#memory) for more on that.
 
 If you are expecting a numeric result, you can use `eval_usize` (panics on
@@ -122,61 +134,74 @@ in an `Option<u64>` yielding the `Scalar` if possible.
 ## Memory
 
 To support any kind of pointers, the interpreter needs to have a "virtual memory" that the
-pointers can point to.  This is implemented in the [`Memory`] type.  In the
-simplest model, every global variable, stack variable and every dynamic
-allocation corresponds to an [`Allocation`] in that memory.  (Actually using an
+pointers can point to.
+This is implemented in the [`Memory`] type.
+In the simplest model, every global variable, stack variable and every dynamic
+allocation corresponds to an [`Allocation`] in that memory.
+(Actually using an
 allocation for every MIR stack variable would be very inefficient; that's why we
 have `Operand::Immediate` for stack variables that are both small and never have
-their address taken.  But that is purely an optimization.)
+their address taken.
+But that is purely an optimization.)
 
 Such an `Allocation` is basically just a sequence of `u8` storing the value of
-each byte in this allocation.  (Plus some extra data, see below.)  Every
-`Allocation` has a globally unique `AllocId` assigned in `Memory`.  With that, a
+each byte in this allocation.
+(Plus some extra data, see below.)  Every
+`Allocation` has a globally unique `AllocId` assigned in `Memory`.
+With that, a
 [`Pointer`] consists of a pair of an `AllocId` (indicating the allocation) and
 an offset into the allocation (indicating which byte of the allocation the
-pointer points to).  It may seem odd that a `Pointer` is not just an integer
+pointer points to).
+It may seem odd that a `Pointer` is not just an integer
 address, but remember that during const evaluation, we cannot know at which
 actual integer address the allocation will end up -- so we use `AllocId` as
-symbolic base addresses, which means we need a separate offset.  (As an aside,
+symbolic base addresses, which means we need a separate offset.
+(As an aside,
 it turns out that pointers at run-time are
 [more than just integers, too](https://rust-lang.github.io/unsafe-code-guidelines/glossary.html#pointer-provenance).)
 
 These allocations exist so that references and raw pointers have something to
-point to. There is no global linear heap in which things are allocated, but each
+point to.
+There is no global linear heap in which things are allocated, but each
 allocation (be it for a local variable, a static or a (future) heap allocation)
-gets its own little memory with exactly the required size. So if you have a
+gets its own little memory with exactly the required size.
+So if you have a
 pointer to an allocation for a local variable `a`, there is no possible (no
 matter how unsafe) operation that you can do that would ever change said pointer
 to a pointer to a different local variable `b`.
 Pointer arithmetic on `a` will only ever change its offset; the `AllocId` stays the same.
 
 This, however, causes a problem when we want to store a `Pointer` into an
 `Allocation`: we cannot turn it into a sequence of `u8` of the right length!
-`AllocId` and offset together are twice as big as a pointer "seems" to be.  This
-is what the `relocation` field of `Allocation` is for: the byte offset of the
+`AllocId` and offset together are twice as big as a pointer "seems" to be.
+This is what the `relocation` field of `Allocation` is for: the byte offset of the
 `Pointer` gets stored as a bunch of `u8`, while its `AllocId` gets stored
-out-of-band.  The two are reassembled when the `Pointer` is read from memory.
+out-of-band.
+The two are reassembled when the `Pointer` is read from memory.
 The other bit of extra data an `Allocation` needs is `undef_mask` for keeping
 track of which of its bytes are initialized.
 
 ### Global memory and exotic allocations
 
 `Memory` exists only during evaluation; it gets destroyed when the
-final value of the constant is computed.  In case that constant contains any
+final value of the constant is computed.
+In case that constant contains any
 pointers, those get "interned" and moved to a global "const eval memory" that is
-part of `TyCtxt`.  These allocations stay around for the remaining computation
+part of `TyCtxt`.
+These allocations stay around for the remaining computation
 and get serialized into the final output (so that dependent crates can use
 them).
 
 Moreover, to also support function pointers, the global memory in `TyCtxt` can
 also contain "virtual allocations": instead of an `Allocation`, these contain an
-`Instance`.  That allows a `Pointer` to point to either normal data or a
+`Instance`.
+That allows a `Pointer` to point to either normal data or a
 function, which is needed to be able to evaluate casts from function pointers to
 raw pointers.
 
 Finally, the [`GlobalAlloc`] type used in the global memory also contains a
-variant `Static` that points to a particular `const` or `static` item.  This is
-needed to support circular statics, where we need to have a `Pointer` to a
+variant `Static` that points to a particular `const` or `static` item.
+This is needed to support circular statics, where we need to have a `Pointer` to a
 `static` for which we cannot yet have an `Allocation` as we do not know the
 bytes of its value.
 
@@ -188,17 +213,19 @@ bytes of its value.
 ### Pointer values vs Pointer types
 
 One common cause of confusion in the interpreter is that being a pointer *value* and having
-a pointer *type* are entirely independent properties.  By "pointer value", we
+a pointer *type* are entirely independent properties.
+By "pointer value", we
 refer to a `Scalar::Ptr` containing a `Pointer` and thus pointing somewhere into
-the interpreter's virtual memory.  This is in contrast to `Scalar::Raw`, which is just some
-concrete integer.
+the interpreter's virtual memory.
+This is in contrast to `Scalar::Raw`, which is just some concrete integer.
 
 However, a variable of pointer or reference *type*, such as `*const T` or `&T`,
 does not have to have a pointer *value*: it could be obtained by casting or
-transmuting an integer to a pointer. 
+transmuting an integer to a pointer.
 And similarly, when casting or transmuting a reference to some
 actual allocation to an integer, we end up with a pointer *value*
-(`Scalar::Ptr`) at integer *type* (`usize`).  This is a problem because we
+(`Scalar::Ptr`) at integer *type* (`usize`).
+ This is a problem because we
 cannot meaningfully perform integer operations such as division on pointer
 values.
 
@@ -207,30 +234,33 @@ values.
 Although the main entry point to constant evaluation is the `tcx.const_eval_*`
 functions, there are additional functions in
 [rustc_const_eval/src/const_eval](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_const_eval/index.html)
-that allow accessing the fields of a `ConstValue` (`ByRef` or otherwise). You should
+that allow accessing the fields of a `ConstValue` (`Indirect` or otherwise).
+You should
 never have to access an `Allocation` directly except for translating it to the
 compilation target (at the moment just LLVM).
 
 The interpreter starts by creating a virtual stack frame for the current constant that is
-being evaluated. There's essentially no difference between a constant and a
+being evaluated.
+There's essentially no difference between a constant and a
 function with no arguments, except that constants do not allow local (named)
 variables at the time of writing this guide.
 
 A stack frame is defined by the `Frame` type in
 [rustc_const_eval/src/interpret/eval_context.rs](https://github.com/rust-lang/rust/blob/HEAD/compiler/rustc_const_eval/src/interpret/eval_context.rs)
-and contains all the local
-variables memory (`None` at the start of evaluation). Each frame refers to the
-evaluation of either the root constant or subsequent calls to `const fn`. The
-evaluation of another constant simply calls `tcx.const_eval_*`, which produce an
+and contains all the local variables memory (`None` at the start of evaluation).
+Each frame refers to the
+evaluation of either the root constant or subsequent calls to `const fn`.
+The evaluation of another constant simply calls `tcx.const_eval_*`, which produce an
 entirely new and independent stack frame.
 
 The frames are just a `Vec<Frame>`, there's no way to actually refer to a
-`Frame`'s memory even if horrible shenanigans are done via unsafe code. The only
-memory that can be referred to are `Allocation`s.
+`Frame`'s memory even if horrible shenanigans are done via unsafe code.
+The only memory that can be referred to are `Allocation`s.
 
 The interpreter now calls the `step` method (in
 [rustc_const_eval/src/interpret/step.rs](https://github.com/rust-lang/rust/blob/HEAD/compiler/rustc_const_eval/src/interpret/step.rs)
-) until it either returns an error or has no further statements to execute. Each
-statement will now initialize or modify the locals or the virtual memory
-referred to by a local. This might require evaluating other constants or
+) until it either returns an error or has no further statements to execute.
+Each statement will now initialize or modify the locals or the virtual memory
+referred to by a local.
+This might require evaluating other constants or
 statics, which just recursively invokes `tcx.const_eval_*`.

src/doc/rustc-dev-guide/src/diagnostics.md

@@ -953,7 +953,7 @@ You can match on the following names and values, using `name = "value"`:
    Only `"MainFunctionType"` is supported.
  - `from_desugaring`: Match against a particular variant of the `DesugaringKind` enum.
    The desugaring is identified by its variant name, for example
-   `"QuestionMark"` for `?` desugaring or `"TryBlock"` for `try` blocks.
+   `"QuestionMark"` for `?` desugaring, or `"TryBlock"` for `try` blocks.
  - `Self` and any generic arguments of the trait, like `Self = "alloc::string::String"`
    or `Rhs="i32"`.
 
@@ -964,6 +964,7 @@ The compiler can provide several values to match on, for example:
   - references to said slices and arrays.
   - `"fn"`, `"unsafe fn"` or `"#[target_feature] fn"` when self is a function.
   - `"{integer}"` and `"{float}"` if the type is a number but we haven't inferred it yet.
+  - `"{struct}"`, `"{enum}"` and `"{union}"` to match self as an ADT
   - combinations of the above, like `"[{integral}; _]"`.
 
 For example, the `Iterator` trait can be filtered in the following way: