diff --git a/compiler/rustc_expand/src/proc_macro_server.rs b/compiler/rustc_expand/src/proc_macro_server.rs index 7bf6502c976..92315c4d4f6 100644 --- a/compiler/rustc_expand/src/proc_macro_server.rs +++ b/compiler/rustc_expand/src/proc_macro_server.rs @@ -1,9 +1,7 @@ use crate::base::{ExtCtxt, ResolverExpand}; use rustc_ast as ast; -use rustc_ast::token; -use rustc_ast::token::Nonterminal; -use rustc_ast::token::NtIdent; +use rustc_ast::token::{self, Nonterminal, NtIdent, TokenKind}; use rustc_ast::tokenstream::{self, CanSynthesizeMissingTokens}; use rustc_ast::tokenstream::{DelimSpan, Spacing::*, TokenStream, TreeAndSpacing}; use rustc_ast_pretty::pprust; @@ -541,6 +539,33 @@ impl server::Ident for Rustc<'_> { } impl server::Literal for Rustc<'_> { + fn from_str(&mut self, s: &str) -> Result { + let override_span = None; + let stream = parse_stream_from_source_str( + FileName::proc_macro_source_code(s), + s.to_owned(), + self.sess, + override_span, + ); + if stream.len() != 1 { + return Err(()); + } + let tree = stream.into_trees().next().unwrap(); + let token = match tree { + tokenstream::TokenTree::Token(token) => token, + tokenstream::TokenTree::Delimited { .. } => return Err(()), + }; + let span_data = token.span.data(); + if (span_data.hi.0 - span_data.lo.0) as usize != s.len() { + // There is a comment or whitespace adjacent to the literal. + return Err(()); + } + let lit = match token.kind { + TokenKind::Literal(lit) => lit, + _ => return Err(()), + }; + Ok(Literal { lit, span: self.call_site }) + } fn debug_kind(&mut self, literal: &Self::Literal) -> String { format!("{:?}", literal.lit.kind) } diff --git a/library/proc_macro/src/bridge/mod.rs b/library/proc_macro/src/bridge/mod.rs index 355ad1f9f88..a2953b68564 100644 --- a/library/proc_macro/src/bridge/mod.rs +++ b/library/proc_macro/src/bridge/mod.rs @@ -107,6 +107,7 @@ macro_rules! with_api { Literal { fn drop($self: $S::Literal); fn clone($self: &$S::Literal) -> $S::Literal; + fn from_str(s: &str) -> Result<$S::Literal, ()>; fn debug_kind($self: &$S::Literal) -> String; fn symbol($self: &$S::Literal) -> String; fn suffix($self: &$S::Literal) -> Option; @@ -315,6 +316,19 @@ impl Unmark for Option { } } +impl Mark for Result { + type Unmarked = Result; + fn mark(unmarked: Self::Unmarked) -> Self { + unmarked.map(T::mark).map_err(E::mark) + } +} +impl Unmark for Result { + type Unmarked = Result; + fn unmark(self) -> Self::Unmarked { + self.map(T::unmark).map_err(E::unmark) + } +} + macro_rules! mark_noop { ($($ty:ty),* $(,)?) => { $( diff --git a/library/proc_macro/src/lib.rs b/library/proc_macro/src/lib.rs index 525fd0fbe34..281999fe715 100644 --- a/library/proc_macro/src/lib.rs +++ b/library/proc_macro/src/lib.rs @@ -91,6 +91,12 @@ pub struct LexError { _inner: (), } +impl LexError { + fn new() -> Self { + LexError { _inner: () } + } +} + #[stable(feature = "proc_macro_lexerror_impls", since = "1.44.0")] impl fmt::Display for LexError { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { @@ -1171,6 +1177,28 @@ impl Literal { } } +/// Parse a single literal from its stringified representation. +/// +/// In order to parse successfully, the input string must not contain anything +/// but the literal token. Specifically, it must not contain whitespace or +/// comments in addition to the literal. +/// +/// The resulting literal token will have a `Span::call_site()` span. +/// +/// NOTE: some errors may cause panics instead of returning `LexError`. We +/// reserve the right to change these errors into `LexError`s later. +#[stable(feature = "proc_macro_literal_parse", since = "1.54.0")] +impl FromStr for Literal { + type Err = LexError; + + fn from_str(src: &str) -> Result { + match bridge::client::Literal::from_str(src) { + Ok(literal) => Ok(Literal(literal)), + Err(()) => Err(LexError::new()), + } + } +} + // N.B., the bridge only provides `to_string`, implement `fmt::Display` // based on it (the reverse of the usual relationship between the two). #[stable(feature = "proc_macro_lib", since = "1.15.0")]