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Author | SHA1 | Date |
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Charles Lew | e60a7d613a | |
Eric Huss | 51817951d0 | |
Eric Huss | 2d51a2aec4 | |
Eric Huss | c495b9660f | |
Eric Huss | 860fe4acc1 | |
Eric Huss | 4e9c91f0ec | |
Eric Huss | 224b6c5306 | |
Eric Huss | bb166095d1 | |
Vadim Petrochenkov | 0bf5d4e44c | |
Charles Lew | 75d48ad86a | |
Charles Lew | 89df289ebe |
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@ -275,6 +275,7 @@ The following is an index of all built-in attributes.
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added in future.
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- Debugger
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- [`debugger_visualizer`] — Embeds a file that specifies debugger output for a type.
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- [`collapse_debuginfo`] — Controls how macro invocations are encoded in debuginfo.
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[Doc comments]: comments.md#doc-comments
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[ECMA-334]: https://www.ecma-international.org/publications-and-standards/standards/ecma-334/
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@ -293,6 +294,7 @@ The following is an index of all built-in attributes.
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[`cfg_attr`]: conditional-compilation.md#the-cfg_attr-attribute
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[`cfg`]: conditional-compilation.md#the-cfg-attribute
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[`cold`]: attributes/codegen.md#the-cold-attribute
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[`collapse_debuginfo`]: attributes/debugger.md#the-collapse_debuginfo-attribute
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[`crate_name`]: crates-and-source-files.md#the-crate_name-attribute
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[`crate_type`]: linkage.md
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[`debugger_visualizer`]: attributes/debugger.md#the-debugger_visualizer-attribute
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@ -139,3 +139,32 @@ When the crate's debug executable is passed into GDB[^rust-gdb], `print bob` wil
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[Natvis documentation]: https://docs.microsoft.com/en-us/visualstudio/debugger/create-custom-views-of-native-objects
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[pretty printing documentation]: https://sourceware.org/gdb/onlinedocs/gdb/Pretty-Printing.html
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[_MetaListNameValueStr_]: ../attributes.md#meta-item-attribute-syntax
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## The `collapse_debuginfo` attribute
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The *`collapse_debuginfo` [attribute]* controls whether code locations from a macro definition are collapsed into a single location associated with the macro's call site,
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when generating debuginfo for code calling this macro.
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The attribute uses the [_MetaListIdents_] syntax to specify its inputs, and can only be applied to macro definitions.
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Accepted options:
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- `#[collapse_debuginfo(yes)]` — code locations in debuginfo are collapsed.
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- `#[collapse_debuginfo(no)]` — code locations in debuginfo are not collapsed.
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- `#[collapse_debuginfo(external)]` — code locations in debuginfo are collapsed only if the macro comes from a different crate.
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The `external` behavior is the default for macros that don't have this attribute, unless they are built-in macros.
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For built-in macros the default is `yes`.
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> **Note**: `rustc` has a `-C collapse-macro-debuginfo` CLI option to override both the default collapsing behavior and `#[collapse_debuginfo]` attributes.
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```rust
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#[collapse_debuginfo(yes)]
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macro_rules! example {
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() => {
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println!("hello!");
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};
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}
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```
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[attribute]: ../attributes.md
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[_MetaListIdents_]: ../attributes.md#meta-item-attribute-syntax
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@ -58,6 +58,7 @@ Please read the [Rustonomicon] before writing unsafe code.
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* Invoking undefined behavior via compiler intrinsics.
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* Executing code compiled with platform features that the current platform
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does not support (see [`target_feature`]), *except* if the platform explicitly documents this to be safe.
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* Performing non-nop coercion on a dangling or unaligned raw pointer.
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* Calling a function with the wrong call ABI or unwinding from a function with the wrong unwind ABI.
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* Producing an invalid value, even in private fields and locals. "Producing" a
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value happens any time a value is assigned to or read from a place, passed to
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@ -159,7 +159,7 @@ Coercion is allowed between the following types:
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### Unsized Coercions
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The following coercions are called `unsized coercions`, since they
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relate to converting sized types to unsized types, and are permitted in a few
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relate to converting types to unsized types, and are permitted in a few
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cases where other coercions are not, as described above. They can still happen
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anywhere else a coercion can occur.
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@ -172,6 +172,8 @@ an implementation of `Unsize<U>` for `T` will be provided:
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* `T` to `dyn U`, when `T` implements `U + Sized`, and `U` is [object safe].
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* `dyn T` to `dyn U`, when `U` is one of `T`'s supertraits.
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* `Foo<..., T, ...>` to `Foo<..., U, ...>`, when:
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* `Foo` is a struct.
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* `T` implements `Unsize<U>`.
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