bjoernager/rust
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Suggest removing unnecessary prefix let in patterns

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This commit is contained in:
Michael Goulet 2022-09-03 05:39:46 +00:00
parent 8c6ce6b91b
commit 91674cc56c
6 changed files with 74 additions and 1 deletions
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24
compiler/rustc_ast/src/token.rs
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@ -398,6 +398,30 @@ impl Token {
}
}
/// Returns `true` if the token can appear at the start of an pattern.
///
/// Shamelessly borrowed from `can_begin_expr`, only used for diagnostics right now.
pub fn can_begin_pattern(&self) -> bool {
match self.uninterpolate().kind {
Ident(name, is_raw) =>
ident_can_begin_expr(name, self.span, is_raw), // value name or keyword
| OpenDelim(Delimiter::Bracket | Delimiter::Parenthesis) // tuple or array
| Literal(..) // literal
| BinOp(Minus) // unary minus
| BinOp(And) // reference
| AndAnd // double reference
// DotDotDot is no longer supported
| DotDot | DotDotDot | DotDotEq // ranges
| Lt | BinOp(Shl) // associated path
| ModSep => true, // global path
Interpolated(ref nt) => matches!(**nt, NtLiteral(..) |
NtPat(..) |
NtBlock(..) |
NtPath(..)),
_ => false,
}
}
/// Returns `true` if the token can appear at the start of a type.
pub fn can_begin_type(&self) -> bool {
match self.uninterpolate().kind {