[WIP] #[fused]

[GrigorenkoPV]

• A more granular take on -Zfused-futures #147129

TODO:

• TODOs in code
• Attribute validation
• mir tests
• support async blocks & async closures
• A proper tracking issue, if this does not get rejected

[rust-log-analyzer]

The job pr-check-2 failed! Check out the build log: (web)(plain enhanced)(plain)

Click to see the possible cause of the failure (guessed by this bot)

 | |
| in this expansion of `find_attr!` (#1)
| in this expansion of `$crate::find_attr!` (#2)
...
81 | $crate::find_attr!($attributes_list, $pattern $(if $guard)? => ()).is_some()
| ------------------------------------------------------------------ in this macro invocation (#2)
...
89 | let i: &rustc_hir::Attribute = i;
| --------------------- ^ expected `rustc_hir::Attribute`, found `rustc_ast::Attribute`
| |
| expected due to this
|
::: compiler/rustc_ast_lowering/src/expr/closure.rs:41:21
|
41 | find_attr!(&e.attrs, Fused(_)),
| ------------------------------ in this macro invocation (#1)
|
= note: `rustc_ast::Attribute` and `rustc_hir::Attribute` have similar names, but are actually distinct types
note: `rustc_ast::Attribute` is defined in crate `rustc_ast`
--> compiler/rustc_ast/src/ast.rs:3404:1
---
| |
| in this expansion of `find_attr!` (#1)
| in this expansion of `$crate::find_attr!` (#2)
...
81 | $crate::find_attr!($attributes_list, $pattern $(if $guard)? => ()).is_some()
| ------------------------------------------------------------------ in this macro invocation (#2)
...
89 | let i: &rustc_hir::Attribute = i;
| --------------------- ^ expected `&Attribute`, found `Attribute`
| |
| expected due to this
|
::: compiler/rustc_ast_lowering/src/expr.rs:359:70
|
359 | ... hir::CoroutineDesugaring::Async { fused: find_attr!(e.attrs, Fused(_)) }
| ----------------------------- in this macro invocation (#1)
For more information about this error, try `rustc --explain E0308`.
[RUSTC-TIMING] rustc_ast_lowering test:false 1.470
error: could not compile `rustc_ast_lowering` (lib) due to 2 previous errors

[rust-bors]

☔ The latest upstream changes (presumably #156649) made this pull request unmergeable. Please resolve the merge conflicts.