Deny #[cfg] and #[cfg_attr] on generic parameters. Fix #51279. Attributes on generic parameters are not expanded, meaning `#[cfg]`, `#[cfg_attr]` and attribute proc macros are entirely ignored on them. This PR makes using the first two attributes an error, because if they are correctly expanded will affect the AST and change code behavior. I'm beta-nominating this, because generic parameter attributes are stabilizing in 1.27, and if we did not reserve their usage, we may never be able to repurpose the meaning of these attributes in the Rust 2015 edition. |
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|---|---|---|
| .. | ||
| diagnostics | ||
| ext | ||
| parse | ||
| util | ||
| ast.rs | ||
| attr.rs | ||
| build.rs | ||
| Cargo.toml | ||
| codemap.rs | ||
| config.rs | ||
| diagnostic_list.rs | ||
| entry.rs | ||
| feature_gate.rs | ||
| fold.rs | ||
| json.rs | ||
| lib.rs | ||
| ptr.rs | ||
| README.md | ||
| show_span.rs | ||
| std_inject.rs | ||
| str.rs | ||
| test.rs | ||
| test_snippet.rs | ||
| tokenstream.rs | ||
| visit.rs | ||
The syntax crate contains those things concerned purely with syntax
– that is, the AST ("abstract syntax tree"), parser, pretty-printer,
lexer, macro expander, and utilities for traversing ASTs.
For more information about how these things work in rustc, see the rustc guide: