diff options
Diffstat (limited to '')
| -rw-r--r-- | compiler/rustc_ast/src/token.rs | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/compiler/rustc_ast/src/token.rs b/compiler/rustc_ast/src/token.rs index 85d9687c6..97dfb7837 100644 --- a/compiler/rustc_ast/src/token.rs +++ b/compiler/rustc_ast/src/token.rs @@ -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 { @@ -436,6 +460,31 @@ impl Token { || self == &OpenDelim(Delimiter::Parenthesis) } + /// Returns `true` if the token can appear at the start of an item. + pub fn can_begin_item(&self) -> bool { + match self.kind { + Ident(name, _) => [ + kw::Fn, + kw::Use, + kw::Struct, + kw::Enum, + kw::Pub, + kw::Trait, + kw::Extern, + kw::Impl, + kw::Unsafe, + kw::Const, + kw::Static, + kw::Union, + kw::Macro, + kw::Mod, + kw::Type, + ] + .contains(&name), + _ => false, + } + } + /// Returns `true` if the token is any literal. pub fn is_lit(&self) -> bool { matches!(self.kind, Literal(..)) |