diff options
Diffstat (limited to 'compiler/rustc_parse/src/parser/attr_wrapper.rs')
| -rw-r--r-- | compiler/rustc_parse/src/parser/attr_wrapper.rs | 53 |
1 files changed, 23 insertions, 30 deletions
diff --git a/compiler/rustc_parse/src/parser/attr_wrapper.rs b/compiler/rustc_parse/src/parser/attr_wrapper.rs index 13a647adfe3..38f18022e3c 100644 --- a/compiler/rustc_parse/src/parser/attr_wrapper.rs +++ b/compiler/rustc_parse/src/parser/attr_wrapper.rs @@ -1,6 +1,6 @@ use super::{Capturing, FlatToken, ForceCollect, Parser, ReplaceRange, TokenCursor, TrailingToken}; use rustc_ast::token::{self, Delimiter, Token, TokenKind}; -use rustc_ast::tokenstream::{AttrTokenStream, AttrTokenTree, AttributesData, DelimSpacing}; +use rustc_ast::tokenstream::{AttrTokenStream, AttrTokenTree, AttrsTarget, DelimSpacing}; use rustc_ast::tokenstream::{DelimSpan, LazyAttrTokenStream, Spacing, ToAttrTokenStream}; use rustc_ast::{self as ast}; use rustc_ast::{AttrVec, Attribute, HasAttrs, HasTokens}; @@ -8,7 +8,6 @@ use rustc_errors::PResult; use rustc_session::parse::ParseSess; use rustc_span::{sym, Span, DUMMY_SP}; -use std::ops::Range; use std::{iter, mem}; /// A wrapper type to ensure that the parser handles outer attributes correctly. @@ -88,7 +87,6 @@ fn has_cfg_or_cfg_attr(attrs: &[Attribute]) -> bool { // // This also makes `Parser` very cheap to clone, since // there is no intermediate collection buffer to clone. -#[derive(Clone)] struct LazyAttrTokenStreamImpl { start_token: (Token, Spacing), cursor_snapshot: TokenCursor, @@ -146,24 +144,23 @@ impl ToAttrTokenStream for LazyAttrTokenStreamImpl { // start position, we ensure that any replace range which encloses // another replace range will capture the *replaced* tokens for the inner // range, not the original tokens. - for (range, new_tokens) in replace_ranges.into_iter().rev() { + for (range, target) in replace_ranges.into_iter().rev() { assert!(!range.is_empty(), "Cannot replace an empty range: {range:?}"); - // Replace ranges are only allowed to decrease the number of tokens. - assert!( - range.len() >= new_tokens.len(), - "Range {range:?} has greater len than {new_tokens:?}" - ); - - // Replace any removed tokens with `FlatToken::Empty`. - // This keeps the total length of `tokens` constant throughout the - // replacement process, allowing us to use all of the `ReplaceRanges` entries - // without adjusting indices. - let filler = iter::repeat((FlatToken::Empty, Spacing::Alone)) - .take(range.len() - new_tokens.len()); + // Replace the tokens in range with zero or one `FlatToken::AttrsTarget`s, plus + // enough `FlatToken::Empty`s to fill up the rest of the range. This keeps the + // total length of `tokens` constant throughout the replacement process, allowing + // us to use all of the `ReplaceRanges` entries without adjusting indices. + let target_len = target.is_some() as usize; tokens.splice( (range.start as usize)..(range.end as usize), - new_tokens.into_iter().chain(filler), + target + .into_iter() + .map(|target| (FlatToken::AttrsTarget(target), Spacing::Alone)) + .chain( + iter::repeat((FlatToken::Empty, Spacing::Alone)) + .take(range.len() - target_len), + ), ); } make_attr_token_stream(tokens.into_iter(), self.break_last_token) @@ -316,7 +313,7 @@ impl<'a> Parser<'a> { .iter() .cloned() .chain(inner_attr_replace_ranges.iter().cloned()) - .map(|(range, tokens)| ((range.start - start_pos)..(range.end - start_pos), tokens)) + .map(|(range, data)| ((range.start - start_pos)..(range.end - start_pos), data)) .collect() }; @@ -346,18 +343,14 @@ impl<'a> Parser<'a> { && matches!(self.capture_state.capturing, Capturing::Yes) && has_cfg_or_cfg_attr(final_attrs) { - let attr_data = AttributesData { attrs: final_attrs.iter().cloned().collect(), tokens }; + assert!(!self.break_last_token, "Should not have unglued last token with cfg attr"); - // Replace the entire AST node that we just parsed, including attributes, - // with a `FlatToken::AttrTarget`. If this AST node is inside an item - // that has `#[derive]`, then this will allow us to cfg-expand this - // AST node. + // Replace the entire AST node that we just parsed, including attributes, with + // `target`. If this AST node is inside an item that has `#[derive]`, then this will + // allow us to cfg-expand this AST node. let start_pos = if has_outer_attrs { attrs.start_pos } else { start_pos }; - let new_tokens = vec![(FlatToken::AttrTarget(attr_data), Spacing::Alone)]; - - assert!(!self.break_last_token, "Should not have unglued last token with cfg attr"); - let range: Range<u32> = (start_pos.try_into().unwrap())..(end_pos.try_into().unwrap()); - self.capture_state.replace_ranges.push((range, new_tokens)); + let target = AttrsTarget { attrs: final_attrs.iter().cloned().collect(), tokens }; + self.capture_state.replace_ranges.push((start_pos..end_pos, Some(target))); self.capture_state.replace_ranges.extend(inner_attr_replace_ranges); } @@ -419,11 +412,11 @@ fn make_attr_token_stream( .expect("Bottom token frame is missing!") .inner .push(AttrTokenTree::Token(token, spacing)), - FlatToken::AttrTarget(data) => stack + FlatToken::AttrsTarget(target) => stack .last_mut() .expect("Bottom token frame is missing!") .inner - .push(AttrTokenTree::Attributes(data)), + .push(AttrTokenTree::AttrsTarget(target)), FlatToken::Empty => {} } token_and_spacing = iter.next(); |