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Make `_` an expression, to discard values in destructuring assignments This is the third and final step towards implementing destructuring assignment (RFC: rust-lang/rfcs#2909, tracking issue: #71126). This PR is the third and final part of #71156, which was split up to allow for easier review. With this PR, an underscore `_` is parsed as an expression but is allowed *only* on the left-hand side of a destructuring assignment. There it simply discards a value, similarly to the wildcard `_` in patterns. For instance, ```rust (a, _) = (1, 2) ``` will simply assign 1 to `a` and discard the 2. Note that for consistency, ``` _ = foo ``` is also allowed and equivalent to just `foo`. Thanks to ````@varkor```` who helped with the implementation, particularly around pre-expansion gating. r? ````@petrochenkov```` |
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| Cargo.toml | ||
| README.md | ||
The rustc_ast 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 dev guide: