Reimplement and complete spanless_eq for the AST
#15599
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r? @Alexendoo rustbot has assigned @Alexendoo. Use |
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clippy_utils/src/ast/mod.rs
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| //! Utilities for manipulating and extracting information from `rustc_ast::ast`. | ||
| //! | ||
| //! - The `eq_foobar` functions test for semantic equality but ignores `NodeId`s and `Span`s. |
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Module docs could do with an update now
clippy_utils/src/ast/spanless.rs
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| (@unequal $($val:tt)*) => { $($val)? }; | ||
| } | ||
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| /// Impls for structs which will be implemented matching the variant and comparing |
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| /// Impls for structs which will be implemented matching the variant and comparing | |
| /// Impls for enums which will be implemented matching the variant and comparing |
| $( | ||
| ( | ||
| $name::$vname { $($fname: $lname),*}, | ||
| $name::$vname { $($fname: $rname),*} | ||
| ) => { | ||
| $(on_unequal!(@$unequal return false);)? | ||
| $(eq_enum_field!($(@$unordered)? cx $lname $rname) &&)* true | ||
| }, | ||
| )* |
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Could we use ${concat} here to allow a similar syntax to the struct definitions?
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I ran into hygiene issues when I tried it the first time, but it might be a thing I can work around.
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Tried some other options. The feature is just not implemented enough currently to work.
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concat doesn't work in nested repetitions and pushing the concat into an inner macro means the generated identifier can only the inner macro can access the name due to hygiene rules. Basically neither of these work:
// with repetitions: ice
$(
(
$var { $($name: ${concat(l, $name)}),* },
$var { $($name: ${concat(r, $name)}),* },
) => $(eq!(${concat(l, $name)} ${concat(r, $name)}))&&*,
)*
// with inner: binding names can't be used outside the `name` macro
$(
(
$var { $($name: name!(l, $name)),* },
$var { $($name: name!(r, $name)),* },
) => $(eq!($name))&&*,
)*
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This replaces the many exported functions that used to exist with a single
spanless_eqfunction. The macros implementing this would be derives, but that's not possible so nearly copying the struct/enum definitions is required.The new implementation has full exhaustiveness checking on both fields and variants. This way any changes made to the AST in rustc will require changes here.
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